Brief Summary of Minutes of Annual Meeting

Present: Noah Adamo, Edward Caswell-Chen, Senyu Chen, Jon Eisenback, Travis Faske, Cynthia Gleason, Saad Hafez, Russ Ingham, Chuck Johnson, Vince Klink, Ron Lacewell, Gary Lawrence, Kathy Lawrence, Haddish Melakeberhan, Henry Nguyen Tom Powers, Phil Roberts, Bob Robbins, Dave Thompson, Brent Sipes, Steve Thomas

Guests: Valerie Williamson, Howard Ferris

Welcome

W3186 and S1066 participant introduced themselves.

Steve Nadler welcomed the group. Nematology at UCD - 20 yrs ago was very vibrant. Retirements have not been replaced. The budget at UCD declined for many years, increasing only recently. The new dean is receptive to nematology so a plant nematologist is being hired and a soil ecologist is in the pipeline.

Administrative Advisers

Ron Lacewell: S1066 started 1 Oct 2015. The annual report needs to be filed in 60 days. Rick Davis is secretary. One regional group met in Washington DC using a workshop format and invited DC project leaders to work on NSF or NIFFA grants. The group may want to think about doing this in 2018 (IPM, precision ag, loss of chemicals as topics).

Dave Thomas: W3186 renews in 2018 and may want to discuss renewal at business meeting. We should think about nominating W3186 for a western award. We need to think about impact - NIFA is talking about capacity building (like this meeting) and their impact. Meeting in Washington DC might be a good idea even in terms of marketing the project/group.

Reports

VA: RK1 and RK2 in Tobacco: project starting; mixed reports on resistance level, some reports RK2 is a quantitative trait, RK2 mechanism not clear and will be investigated, variation within a cultivar really speaks to the need for isogenic lines; Very good discussion and ideas shared; Tobacco acreage world-wide is relatively stable. China and India are large producers. Lots of good work being conducted in this crop.

VA: A first report of Meloidogyne mali in America from NY was made. Mm has a wide host range including ferns but not grasses, was originally described in Japan, and a few years ago appeared in Europe on elm. First in the Netherlands then Italy, places associated with elm breeding, so maybe Mm was imported into Netherlands along with root stock from Japan.

VA: Nematodes on rice and vegetables in Cambodia were few on vegetables grown using plastic mulch. There were no organisms associated with these vegetables perhaps because the soil had lots of chemigation. Some Rotylenchulus was found in vegetables not grown with plastic mulch - lots of rootknot and lance nematodes were also found. In rice, lots of Hirschmanniella was found and maybe caused 20-30% yield loss.

MN: Winter oil seed cover crops pennycress and camelina oil seed crops are being tested and SCN reproduction is good on pennycress. SCN reproduction on resistance soybean increasing since 1997 on PI 88788, PI 209332, and PI 548316. SCN reproduction on PI 567516C is low and it is a new source of resistance for many SCN type. PI 567516C appears to be a different gene. QTL shows it to be a novel R gene on chromosome 10. Also QTLs on chromosome 8 and 18 are not rhg or Rhg. Breeding trials suggest that it might be a good source of resistance. Fungal communities in soybean were studied for biological control in a site established in 1982 using metabarcoding. Differences between corn and soybean and among rotations is evident.

MO: New resistance sources for SCN  in the PI collection are being evaluated along with assays for rootknot and reniform nematode resistance. Used rhg1 and Rhg4 to group soybean based on copy number and presence of the genes. A medium copy number is like Peking, a high copy number is like PI 88788. A third group with low copy number and no Rhg4 is the source for new SCN resistance genes. Copy number is related to resistance level. PI 567516C has no rhg1 or Rhg4 but has a major QTL on chromosome 10. PI 567305 has a QTL on chromosome 8 and 18. Both PI have resistance to SCN, rootknot, and reniform. This is a method to deal with loss of resistance in the field to SCN. Currently using a KASP genotyping assay to verify the data. The project is collaborating with MN and AR.

AL: Mi found in cotton, Ma in peanut but not many other species. Plant health improvement with growth regulators (hormones), starter fertilizers and nematocides; prescription combinations (nematicides and starter fertilizers) might be best but do not add too much; Tumeric lines are all susceptible to rootknot nematode; Caternaria fungus found in rootknot, reniform, and cyst greenhouse cultures - able to culture on beef extract agar; fungi seem to infect stressed nematodes rather than vibrant nematodes; cotton yield loss to reniform was 36-57%; Velum did well in controlling reniform damage, on cotton velum not as effective in controlling damage but very cultivar dependent; earthworms will pass viable nematodes

MS: Defense against soil borne pathogens gene discovery is the thrust now. SCN infection linked to specific cell types, interest is in those genes that are expressed in and define the resistant cell, a-SNAP is involved which a secretion gene, looking at 200 genes and level of resistance, looking at gene families now and other families

AR: Rooknot nematode on soybean has become #1 problem, Mi is the common species, moved from cotton monoculture and the use of soybean Group 3 and 4, most cultivars do not have Mi resistance (89% are susceptible) or even frogeye leaf spot resistance,  Telone II availability is limited for soybean growers, ILeVo good, Votivo not bad, Luna (Velum) not having an effect, Roundup Ready plants not being used so frequently (lots of roundup resistant pigweed), Liberty Linked is the popular herbicide transgenic now but there is movement to dicamba resistance.

AR: 142 soybean cultivars screened - 5 with resistance to reniform nematode, 216 breeder lines - 22 resistance to reniform nematode, 21 PI with 14 very resistant, doing similar resistant screening since 1994 - 215 PI evaluated and will conduct a meta-analysis; Meloidogyne hispanica identified in 2 sites in agricultural fields, Meloidogyne incognita is the most common species. Have also found Meloidogyne arenaria, hapla, haplanaria, marylandi, and partityla. Meloidogyne  partityla also reproduces on nutall oak and overcrup oak.

VA: Host resistance to rootknot is need in tobacco now (growers use rotation and resistance for Globodera) and some lines have resistance (RK2). Brazil and China breeders working to incorporate rootknot resistance into cultivars; Luna, Telone II, AITC (costly), and Magestene (as organic alternative) all showed some nematode control; Nimitz performs sporadically so placement is critical for efficacy.

MI: Meloidogyne hapla and lesion nematodes are common in vegetable fields, plant-parasitic nematodes are most common in agricultural soils. Cover crops for nematode management are desired and being investigated. Nematodes may not be biggest factor in vegetable yield loss.

OR: Nothing to say about Globodera ellingtonia; Meloidogyne chiwoodi on potato can start out low but still reach high levels, threshold is less than .4 nematodes/250 cc soul, Vydate no longer available in sufficient quantity which increases demand for Telone which is in limited supply, metal sodium has environmental concerns, so growers want and need for biological controls, Sudan 79  does not allow Mc reproduction, incorporating biomass reduces Mc with a high rate of sudan 79 the best in reducing, applying biological control products early in the season (Bio Blend, Hyper Galaxy, Melocon) provide some reduction in J2 soil and in eggs on roots, Melocon was the best in reducing egg populations, results are encouraging.

HI: Mint is evaluated as a living mulch for vegetable production, mint is not a host to rootknot or reniform nematodes, the mint did not adversely affect yield of eggplant and added 17% profit; Entomopathogenic nematodes are more common in Hawaii than thought, Oschious is the most common genus.

ID: In potato found Ditylenchus medicargis, a new record for the US; mint survey shows lesion, northern rootknot, pin, and other nematodes, stand loss caused by lesion and verticillium is severe, plants unable to recover after cutting, tested products do not provide control, furrow irrigation exacerbates nematode problems (especially pin nematode);  tolerant beet cultivars in conjunction with low levels of Telone II look promising, green manure crops can increase yield; Vapam + vydate or + movento or the new chemistries provide alternatives to address the limited supply of Telone II, BioAct active ingredient is paceliomyces, adding Adsorb or similar products with metam sodium increases its efficacy.

NM: Ditylenchus species genetic variation (18S ITS I & II and 24S) through direct sequencing, some deep sequencing of nematode samples spiked with rootknot and stem nematodes but has required some bioinformatics to analyze; D. dipsaci was found in NM for first time never previously found in alfalfa even; Xeriscape plants susceptible to M. incognita being tested in a high foot traffic microplot test (residents can see the experiment and signs are posted to explain to public); Avid and Nimitz on turf for ring looks very good, now looking for something to manage lesion nematode control; Nimitz for control lesion in pinto beans and for Mi in vineyard grapes.

WA: Effectors and phytohormones, nematode secretions and Jasmonic acid; Interested in Mh265 specific to nematodes and Mi131 has homology to actin, Mh265 looks to be involved in basal defense response by plants, Mi131 profiling domain but why secrete something that binds to actin? Sequesters actin and therefore interferes with cytoskeleton which might be responsible for lack of cytokinesis in giant cells; Mc RMc1(blb) gene to be used to study virulence and avirulence in M. chitwoodi.

CA - Riverside: Carrots, resistance and Meloidogyne; Range of resistance to Mi in carrots from many sources/backgrounds, Galling is the problem so we want to stop galling on the tap root, 4 major and 1 minor chromosome regions/QTL for Mi resistance, Carrot resistance panel set up and tested across rootknot species (11 resistance X 49 nematode isolates of Mi, Mj, Ma, Mh) not finding naturally occurring virulence in Mi populations, need to introduce resistance into commercial cultivars, not as much resistance to Mh found in the panel and the panel shows greater variation existing in Mh; 25 Mi virulent on Mi-1 and Cowpea Rk does not appear to be any cross virulence or cross selection from virulence from tomato to carrot or cowpea to carrot; looking to build profiles of virulence in Mi and it seems like there might be a cross virulence selection but virulence on Mi1 seems to have virulence on Rk

NE: Barcoding for Pratylenchus and Aphelenchoides, navigating database purgatory, east-west transect sample from Kansas to Nebraska and COI gene , first see 6 clades based on COI, also used keys and BLAST, also doing greenhouse reproduction and this shows that all isolates reproduce on corn, soybean, wheat at some level, not everything with COI tree, Blast and keys, sometimes the outputs seem to suggest that there may be errors; Aphelenchoides besseyi on rice - data base contains so much stuff called besseyi that is probably not besseyi, very muddled situation in gene database.

CA - Davis: Snails and movement of plant pathogens could be accidental associations, phoresis, dispersal may occur with pathogens, found a variety of nematodes in snails (free living and plant parasitic), the snails are sampling the environment; Active nematodes were recovered up to 168 hours after consumption, these nematodes are infective after passing through the snail digestive track; snails could serve as a bio-sentinel organism.

CA - Davis: Less diversity within asexual Meloidogyne species than within one sexual Meloidogyne (speakerdeck.com/davelunt); what attacks nematodes to roots - heat stable, hydorphyllic not charged substance, active fraction is about 1000 daltons secondary metabolite; ascaricides can be attractive to males; CRISPR micro-injection into germline in C. elegans, looks to be successful in injecting M. hapla males.

Joint Business Meeting

Approval of 2015 minutes:

S1066 – approved

W318 - approved

W3186:

W3186 Host Russ Ingham meeting in Oregon targeting 1-2 November 2017 (Saad Hafez has offered Boise ID as an alternative if needed).

Brent Sipes will serve as Chair 2017, Ed Caswell-Chen will serve as Vice Chair, Cynthia Gleason will serve as Secretary 2017. Reports to B. Sipes by 18 November 2016.

W3186 will rewrite next year. Updating and perhaps minor tweaking of the existing project is probably what is needed. The new project will must be submitted in January 2018. NIFA emphasized broad categories of existing RFPs (will need to adjust based upon new priorities). The group will correspond with suggestions over email. It is important to articulate the success and impacts of the project in the revision. We will need to have a discussion if we want to modify the objectives. Phil Roberts will start a new draft and circulate for input. The project should be formulated as key impact areas and demonstrate multi state impact.

We will think about having a meeting in Washington DC in 2018 or some time thereafter.

S1066:

S1066 Chair Rick Davis will host the 2017 meeting in North Carolina. Don Dickson will serve as Secretary in 2017 going on to chair and host the meeting in 2018. Please have reports to Travis Faske by 18 November 2016.

Meeting Adjourned at 11:45 am 11 November 2016.

Objective 1:   Advance the tools for identification of nematode species and characterization of intraspecific variability.

Alabama, (K. Lawrence):  Meloidogyne species identification is important for growers in the state of Alabama, because it helps in the decision of crop rotations.  Depending on what species is present in a root-knot nematode infestation, a year to year crop rotation can be implemented as a means to help with control.  It also helps growers determine if resistant varieties are needed based upon certain root-knot species levels.  Currently, identification of Meloidogyne species for Auburn University is performed via a host-differential test.  The host-differential test is a commonly used method for species identification.  This test can take as long as forty-five to sixty days for successful species determination.  A broader assay is currently in development to expedite the identification time to as quickly as a week.  This process includes morphological measurements as well as the use of molecular techniques to provide an accurate depiction of what species is present.  The molecular technique involves the use of a single Meloidogyne (root-knot) second stage juvenile that is ruptured in a droplet of water, and then added to a PCR mixture.  Primers currently used screen for the following common Meloidogyne species: M. incognita, M. arenaria, M. javanica, M. hapla, M. chitwoodi, and M. enterolobii.  Samples are currently being taken of known root-knot infested fields throughout the state of Alabama for analysis.  M. incognita, or the southern root-knot nematode, has been the most prevalent species found and identified as of this point.  M. arenaria, or peanut root-knot nematode, has also been discovered on peanut fields in the southern part of the state.  Each of these species has been identified via a host-differential test.  For M. incognita, gall formation and nematode egg numbers were present on cotton, pepper, watermelon and tomato, showing the presence of M. incognita race 3.  For the M. arenaria population, galls and nematode eggs were present on tobacco, pepper, watermelon, peanut, and tomato.  This shows that the species present was M. arenaria race 1.  Morphological measurements and features for adult males, females and juveniles were then taken of each of these species populations, and were found to fit the expected ranges for each relative species.  M. incognita has successfully been identified by a PCR technique using the primer set Inc-K14.  M. arenaria has yet to be identified via molecular techniques.  All primers screened so far for M. arenaria have failed to show amplification.  The next steps in this research include continued work on developing a PCR technique for species differentiation, as well as sequencing several genetic regions in both populations to help further differentiate the species.  Going forward, we hope to build a complete diagnostic assay that can positively identify all commonly found species of Meloidogyne as quickly, efficiently, and accurately as possible.

Arkansas (R. Robbins):   I worked with soybean researchers from Missouri and Georgia to identify 21 soybean Plant introductions reported to have Soybean Cyst Nematode resistance for reniform nematode (Rotylenchulus reniformis) reproduction (resistance). Of the 21 PI’s 14 were resistant (PI 407788A, PI 424608A, PI 437654, PI 437690, PI 468915, PI 507354, PI 567230, PI 567305, PI 567336A, PI 567336B, PI 567516C, PI 603445B, PI 612611, PI 658519) to reniform and one (PI 404198B) was moderately resistant. I also tested 223 RIL for reniform reproduction of which 15 were as resistant as resistant checks Hartwig and Anand.

During several years (1994 to 2016) I have tested 215 PI lines for reproduction (Resistance) for reniform nematode. Of these 215 tests 127 were different. The remaining lines were tested from 2 to 5 times. The lines tested more than once generally agreed closely in results.

Louisiana (McGawley, E.C. and Overstreet, C.):  The three new students in the nematology project at LSU have made progress in attempts to:

1. To determine whether or not it is possible to develop an abbreviated host assay for differentiating virulence phenotypes of Rotylenchulus reniformis employing selected cultivars of soybean and cotton.
2. To determine whether or not the abbreviated assay can be performed in a laboratory environment using plants grown either in soil-filled polystyrene centrifuge tubes or in a soil-free growth pouch system.
3. To attempt to employ microsatellite marker technology to distinguish among virulence phenotypes of Rotylenchulus reniformis.

 Two full-season microplot experiments were conducted to evaluate the damage potential of a plant parasitic nematode (PPN) community on St. Augustine and centipede turfgrasses grown in different soil types.  Nematode genera associated with both turfgrasses included Criconemella, Helicotylenchus, Meloidogyne, Pratylenchus, Tylenchorynchus and Tylenchus spp. In 2012, nematodes did not cause significant damage to either turfgrass, but soil type exhibited an effect on plant growth parameters.  In 2013, when there was significant nematode-related injury to both turfgrasses, there were no significant effects of soil type on plant growth parameters.

 Virginia (J. Eisenback):  Meloidogyne mali from a declining hedge of Manhattan Euonymus (Euonymus kiautschovicus Loes.) growing at a private residence in Harrison, N.Y., was identified for the first time in North America. The roots were disfigured with swellings and galls that contained females of a root-knot nematode. The perineal pattern was rounded, and contained a conspicuous tail terminus flanked by two short lateral ridges that rapidly fade beneath the surface of the cuticle. Additional morphological characters that were consistent with those of M. mali included the shapes of the stylet in all three life-stages, morphology of the male head, and shape of the juvenile tail. Likewise, measurements of second-stage juveniles were comparable to those in the original description. PCR was performed for the D2-D3 region of the 28S ribosomal RNA gene and the sequences were blasted against Genbank for matches. Although there were a few nucleotide differences among this and other isolates of M. mali, the similarity ranged from 96 to 98% and confirms the identity of this population. The apple root-knot nematode has been reported on numerous plant species in Japan, and on elm in Italy and the Netherlands. Meloidogyne mali may have been spread from the Netherlands to Italy on infected elm nursery stock in the breeding program to fight Dutch elm disease (DED). The fungus that causes DED was probably introduced from Asia into Europe and finally to the United States. Likewise, the nematode may have been introduced by the same program. Initial breeding for resistance to DED in the U.S. occurred at two major locations: Madison, Wisconsin and Morristown, N.J. The location of the infestation in Harrison, N.Y. is very close to Morristown. Meloidogyne mali has a very broad host range parasitizing fruit and nut trees, flowering trees, shade trees, woody shrubs, vines, brambles, vegetables, row crops, flowers, weedy plants, and ferns.

 Objective 2:  Elucidate molecular and physiological mechanisms of plant-nematode interactions to improve host resistance.

Tennessee (Tarek Hewezi, Feng Chen and Reza Hajimorad):  Soybean cyst nematode (SCN, Heterodera glycines), injects an array of effector proteins into soybean root cells to establish an extended parasitic relationship with soybean plants. A novel SCN effector protein (HgGLAND18), which is expressed exclusively in the nematode dorsal gland cell during all parasitic stages, was functionally characterized using a number of molecular and genetic approaches, including host-induced RNAi, overexpression, and agroinfiltration assays. We established that this Plasmodium-like virulence effector is vital for SCN parasitism of soybean, and functions in suppressing both basal immune responses and hypersensitive cell death.

MicroRNA genes have recently emerged as key regulators of plant responses to infection by cyst nematodes.  A set of soybean miRNA genes was identified as epigenetically regulated by SCN during infection. The functional roles of these miRNA genes in mediating soybean responses to SCN parasitism are being assessed using transgenic hairy root system. Preliminary results points into a critical role of these genes in determining the outcomes of SCN × soybean interactions.

The role of a soybean salicylic acid methyl transferase gene (GmSAMT1) in mediating soybean resistance against various SCN races was studied using stable transgenic approach. Several independent transgenic soybean lines overexpressing GmSAMT1 genes were generated and assessed against multiple races of SCN. We found that overexpression of GmSAMT1 confers significant levels of resistance against three SCN HG-types, including HG type 1.2.5.7 (race 2), HG type 0 (race 3), and HG type 2.5.7 (race 5). Interestingly, no statistically significant differences in soybean seed yield between the transgenic soybean lines and the non-transgenic controls were detected under filed conditions. Thus, resistance against various SCN-Hg types can be achieved without compromising seed yield. 

Missouri (H. Nguyen): Discovery of new resistance sources:  A diverse set of 106 soybean germplasm, including exotic plant introductions (PIs), breeding lines, and varieties, was sequenced using the next-generation sequence (NGS) technology and was phenotyped for soybean cyst nematode (SCN) resistance. Genome-wide haplotype and structural variation analysis identified 41 lines with more than one copy of resistance genes of the Rhg1 locus and the presence of the Rhg4 locus. Of these, eight lines showed strong SCN resistance with multiple copies of the Rhg1 genes. Three lines did not have any known SCN resistance genes, but showed resistance to multi-SCN races, suggesting that these lines might have novel resistance genes (Qiu et al., in preparation).  In addition, 120 new soybean PIs from the USDA Soybean Germplasm Collection with resistance to one or more SCN races were evaluated for other nematodes, e.g. root-knot (RKN) and reniform (RN) nematodes. Among these, 24 accessions showed good resistance to both RKN and RN.

Genetic analysis of new sources:  PI 567305 was reported to be highly resistant to multi-nematode species, e.g. SCN, RKN, and RN (Nguyen Lab, unpublished data). Genetic analysis was conducted in a recombinant inbred line (RIL) population to identify and map genomic regions for multi-nematode resistance. Two major QTL responsible for resistance to different SCN races were consistently mapped at the same genomic locations on Chrs. 10 (LG O) and 18 (LG G), as previously reported in PI 567516C.  Whole-genome sequencing data and haplotype analysis indicated that these two PIs shared similar genome component in both QTL regions. Fine-mapping and cloning of these QTL are in progress in an effort to pyramid these QTL and the Rhg1 and Rgh4 loci for improving nematode resistance.  In addition to SCN resistance, this PI was also resistant to RKN and RN. Genetic mapping identified and mapped the same major QTL associated with RKN resistance on Chr. 10 (LG O) and Chr. 13 (LG F), as previously reported (Xu et al. 2013). For RN resistance, one major QTL was detected and mapped on Chr. 18 (LG O) as previously reported in PI 567516C.

PI 438489B was reported to be highly resistant to multi-SCN races. Genetic analysis confirmed two major loci, Rhg1 and Rhg4, for resistance to multi-SCN races in this accession (Vuong et al. 2011) and three significant QTL for resistance to RKN on Chrs. 8, 10, and 13 (LGs A2, O, and F, respectively) as previously reported (Xu et al. 2013). For the identification of RN resistance, greenhouse phenotyping to evaluate a RIL mapping population was completed. Genetic analysis to map genomic regions associated with RN resistance is underway.

Fine-mapping of novel QTL:  An exotic germplasm, PI 567516C, was identified to be highly resistant to multi-races of SCN. Genetic analysis detected and mapped novel quantitative trait loci (QTL) on Chr. 10 (LG O) and Chr. 18 (LG G). The Chr. 18-QTL was genetically distant from the known Rhg1 locus and tentatively designated as the 2^ndG QTL (Vuong et al. 2010). Several backcrossing populations were developed to fine-map these QTL regions. More than 2,200 BC4F2 plants were genotyped and phenotyped, allowing to narrow the Chr. 10-QTL region to a 115-kb interval. In addition, 41 BC4F2:3 families were selected and grown in a greenhouse of the University of Missouri for the development of near-isogenic lines (NIL). A subset of NILs were harvested and greenhouse tests to confirm the SCN resistance phenotypes is underway. For the 2^ndG QTL, more than 1,000 BC4F2 seeds were grown in a greenhouse. Genotyping was initiated to identify BC4F2:3 families, aiming to the development of NILs and fine-mapping of this QTL region.

 Mississippi (G. Lawrence, V. Klink): Identification of a receptor functioning during defense to a parasitic nematode:  Genes that have been shown to be expressed in G. max in a Heterodera glycines-induced feeding structure called a syncytium undergoing a resistant reaction in a have been identified. The identified genes then have been engineered to be expressed in a Glycine max genotype that is normally susceptible to H. glycines. The consequence of the overexpression of these genes was suppressed parasitism. In contrast, parasitism was increased by reducing the expression level of these same genes in a G. max genotype that is normally resistant to H. glycines. The combination of these outcomes indicates that the gene products perform a function in defense.

 A developmental genetics approach to demonstrate a conserved genetic apparatus functions in defense to parasitic nematodes:  Genes functioning in membrane fusion were originally identified genetically in the baker’s yeast, Saccharomyces cerevisiae, and are found in all eukaryotes. Components of the membrane fusion unit function in the plant genetic model Arabidopsis thaliana during its defense to shoot pathogens. Regarding defense, little is understood about a root function. Experiments in Glycine max (soybean) have provided an opportunity to perform such studies, revealing that syntaxin 31 and alpha soluble NSF attachment protein (-SNAP) are expressed under natural conditions in root cells undergoing defense to parasitism by the nematode Heterodera glycines. Other genes functioning in membrane dynamics are also expressed, but have no obvious role in root biology or resistance. Presented here, G. max homologs of membrane fusion genes are shown to function in the resistance of G. max to H. glycines. In contrast, other genes functioning in various aspects of vesicle transport do not appear to function in resistance. These experiments point to the specificity of the transgenic approach used in the analysis and the process of resistance itself. Experiments show that the membrane fusion apparatus functions with a number of other genes during the process of resistance.

 North Carolina (E. Davis, C. Opperman, D. Bird):  A project was completed in collaboration with Pioneer Hi-Bred International, Inc. to identify a suite of new genes from the soybean cyst nematode (SCN), Heterodera glycines, that encode effector molecules secreted from the nematode during parasitism of soybean roots.  A new method of mild fixation, staining, and isolation of the SCN esophageal gland cells that produce the secreted effectors was used to isolate mRNA and identify 18 new expressed effector genes from SCN.  The function and potential plant host-derived RNA interference (RNAi) silencing of each new SCN effector gene are currently under investigation to identify vulnerable targets to develop novel resistance to nematodes in crop plants.

The genome sequence and annotation of the lesion nematode, Pratylenchus coffeae, was completed during this time period by North Carolina researchers.  Of particular interest was the relatively small size of the P. coffeae genome compared to other known nematode genomes, suggesting that P. coffeae has evolved a minimal essential genome to function as a parasite of plants.  The P. coffeae genome contains a number of hydrolytic enzymes common to other plant nematodes and a few other effectors, but does not carry these genes in high number.  The data suggest that P. coffeae may represent an ancient ancestor to modern plant nematodes, or conversely, that P. coffeae has lost many of the genes present in other plant nematode species to reduce to the bare essentials necessary to function as a migratory endoparasitic nematdode.

Virginia (J. Eisenback):  The transcriptome of Pratylenchus penetrans generated by Illumina mRNA sequencing analysis has been released and the raw sequencing reads have been deposited at the NCBI under the BioProject ID PRJNA304159. We have validated by qPCR analyses gene expression profiles belonging to the main defense pathways of two economic important plants (soybean and lilies) against P. penetrans using a series of time points.

The reference transcriptome assembly generated for P. penetrans is currently undergoing a more detailed analyses for the identification and characterization of parasitism genes of P. penetrans. The predicted transcripts containing a signal peptide and no transmembrane domain were ranked according their normalized expression. This allowed us to look at the highly expressed nematode secreted candidate genes, and to increase the likelihood of identifying genes relevant for parasitism. We selected a set of genes for which there is evidence for expression in planta base on our recent transcriptome analyses and conducted in situ hybridization for a set of 50 genes, and studied their localization within the nematode tissues. We were able to validate and confirm the specific localization of transcripts encoding for orthologues of known parasitism genes from other plant-parasitic nematodes (e.g. cell wall degrading enzymes), as well as new pioneer genes in the esophageal glands of P. penetrans.

RNAi interference represents a powerful technique for the analysis of gene function, and has shown promising results in the control of plant pathogens, including plant-parasitic nematodes. We have validated this proof of concept and conducted RNAi experiments against metabolic and parasitism related genes of P. penetrans. Two genes related to locomotion and muscle architecture (Pp-pat-10 and Pp-unc-87), which were highly abundant among the nematode transcripts identified from infected roots, provide significant nematode reduction after plant-mediated RNAi silencing. In addition, other parasitism-related genes involved in different molecular pathways (unpublished data) have been analyzed, with some of them showing a significant reduction of nematodes.

After validation the efficiency of overexpression two cystatin genes (OC-I and OC-II), and two Bt genes (Cry5B and Cry6A) against P. penetrans using soybean hairy roots, the reductions on the nematode development reached a only maximum of 15%.

Objective 3:  Integrate nematode management agents (NMAs) and cultural tactics with the use of resistant cultivars to develop sustainable crop production systems.

Alabama (K. Lawrence):  Heterodera glycines and Rotylenchulus reniformis cultures in our greenhouse have a fungus colonizing the body of the nematodes juveniles. Sporangia form inside the nematodes bodies producing zoospores. We have observed the sporangia forming germination tubes to release the zoospores outside the cuticle of the nematodes. The morphological characteristics indicated that this fungus is a Catenaria spp. The objectives of this study were to determine the best isolation medium, the optimum fungal growth temperature, and define the infection rates on the three nematodes. An individual H. glycines or R. reniformis vermiform nematode colonized with Catenaria spp. was placed on either 4% BEA (Beef Extract Agar), PDA (Potato Dextrose Agar), PCA (Potato Carrot Agar), OA (Oatmeal Agar), or CMA (Corn Meal Agar) and allowed to grow for 7 days and assessed for fungal growth. The results indicated the 4% BEA was the only media that was able to support growth of the Catenaria spp. isolates from either of the nematode genera. Isolates of the Catenaria spp. were transferred to new 4% BEA plates and incubated at temperatures of 10, 20, 25, 30, 35, and 40°C for 15 days. The optimum growth temperature for the isolates was found to range from 25 to 35°C (P ≤ 0.05). Little to no fungal growth was observed at 10 or 40°C. H. glycines and M. incognita second stage juveniles (J2) and eggs and R. reniformis life stages and eggs, both live and dead were placed in different wells of the 96-well plates. One infective nematode was added to each well to observe the infection rates over a 20-day period. M. incognita infection rates for dead J2 and dead eggs were 100% and 75% respectively, which were significantly higher than live J2 which exhibited an infection rate of 3% (P ≤ 0.05). The infection rate for live M. incognita eggs was 50% with no significant difference from living J2 or dead eggs or J2 nematode colonization. For H. glycines infection rates of the dead J2 were 50% at 20 days. For R. reniformis infection rates of the dead vermiform were 25% at 20 days. No infection was found on the live H. glycines and R. reniformis. Future work will include greenhouse testing to assess the biological control ability of this Catenaria spp. on H. glycines, R. reniformis, and M. incognita.

Field trials were conducted in Alabama to test the effects of adding plant hormones, starter fertilizers, and nematicides to Gossypium hirsutum, cultivar Fiber Max 1944 GLB2, in the presence of Meloidogyne incognita. Treatments for the trial included a water control, the nematicides Velum Total or Vydate CLV applied as an in-furrow spray, Ascend (plant growth hormones), Sure-K + Micro 500 (a starter fertilizer blend), and all possible combinations of the nematicides, hormones, and starter fertilizers. At 43 DAP all nematicide treatment combinations significantly reduced nematode populations by more than 70% compared to the untreated control. Overall Velum Total combinations had a larger reduction of nematode populations as compared to other treatments. The 63 DAP sampling period showed a similar trend with all nematicide combinations reducing nematode populations by 20% or greater compared to the untreated control. The Vydate CLV in-furrow spray with the addition of the starter fertilizer blend significantly reduced nematode populations at the second sampling period at 63 DAP. Seed cotton yields varied from 4412 to 5500 lbs. per acre, in the untreated control and the Vydate CLV in-furrow spray respectively. Velum Total and Vydate CLV applied separately as in-furrow sprays both increased seed cotton yield by an average of 1000 lbs. per acre over the control.

Arkansas (R. Robbins): In 2016 I tested 142 soybean entries new to the Arkansas Soybean Variety Testing program soybean. Five entries (Armor AR5206C, Dyna-Gro S49XS76, Delta Grow DG4995 RR, Go Soy 49G16, Go Soy 5214GTS) of the 142 were not different than the resistant checks Anand and Hartwig. These five entries may be useful in a cotton-soybean rotation to reduce numbers

I tested 216 lines from Southern Soybean Breeders (5 from USDA Jackson TN; 19 from South Carolina (Clemson); 35 from Arkansas; 17 from Missouri; 96 from Southern Illinois; and 44 from Georgia) for resistance to the reniform nematode in soybean breeder lines. Of these 216 lines 19 with RI’s of 1.44 to 3.62 were not different than the resistant checks Anand and Hartwig. The susceptible lines RI’s ranged from 5.22 to 280. The 19 resistant lines may be useful in breeding for reniform resistance.       .

Arkansas (Faske, T. R.):  Evaluation of host plant resistance in soybean.  Some 16 MG IV and 18 MG V soybean cultivars were evaluated for susceptibility to southern root-knot nematode in one field trial.  Most of all entries were very susceptible, which had a negative impact on yield.  However, three MG IV entries and four MG V entries were identified to have some level of resistance that was better than the highly susceptible entries. 

Because of the lack of resistance in soybean cultivars, producers turn to nematode management agents.  Three field experiments were conducted in soybean and six experiments in cotton to evaluate experimental and commercially available seed treatment nematicides on susceptible and moderately resistant host.  These products included; new biological seed treatments, ILeVO, COPeO, Velum Total, Propulse, and VOTiVO.  Of the seed treatments tested, the commercially available nematicides were similar in efficacy, but did not provide consistent degree of suppression among host or Pi.  One of the commercially available nematicides is fluopyram, a succinate dehydrogenase inhibitor fungicide, which was being evaluated as a seed treatment and in-seed-furrow spray for suppression of root-knot nematode.  

Due to observations in the field, experiments were conducted in the lab and greenhouse to determine the movement of fluopyram in sandy soil using a nematode bioassay. Fluopyram does affect nematode motility and there appears to be some movement in sandy soil.

Tennessee (Tarek Hewezi, Feng Chen and Reza Hajimorad): In search of new viruses of SCN, we performed RNA sequencing on the transcriptomes derived from a mixture of laboratory races 1, 2, 3, 5 eggs and J2s samples while using Illumina MiSeq platform. For eggs and J2s, a total of 24,999,824 (eggs) and 24,989,728 (J2) molecular sequence reads in pairs were obtained. Following all the necessary molecular trimmings and other processing a total of 18,831 and 17,565 contigs for eggs and J2s were obtained, respectively. Analysis of these contigs for the presence of viral sequences is currently under way.

To examine possible existence of DNA viruses in SCN, high quality DNA was extracted from the J2 stage of SCN race 3 and utilized for whole genomic DNA sequencing through Illumina HiSeq platform. This resulted in a total of 304,730,696 sequence reads in pair.  Following trimming and mapping to the SCN genome, the non-SCN-like reads were assembled into 195,126 contigs. The classification of the candidate viral genes and their validation is currently underway. To facilitate evaluation of potential pathogenic virus in virus-free nematode population, sugar beet cyst nematode (BCN), closely related to SCN, was also studied by RNA sequencing using transcriptomes derived from eggs and J2s. Following sequencing, nematode sequences were timed and the non-nematode-like sequence reads were assembled into a total of 35,232 and 26,196 contigs for eggs and J2, respectively. To date we have identified one novel virus genome, designated as beet cyst nematode virus-1 (BCNV-1), in these sequence pool. This novel virus was also detected in BCN populations from Iowa and Missouri by RT-PCR as well. Further characterization of this novel virus is currently underway.

Louisiana (McGawley, E.C. and C. Overstreet):  A trial was conducted with soybeans to evaluate the influence of soil texture as measured by apparent electrical conductivity (EC_a) and the response of the nematicides Telone II at 3 gal/acre, Avicta Complete Soybeans, the combination, and an untreated control. Both reniform and Southern root-knot nematodes were present throughout the field. The field was divided into 5 zones based on EC_a-dp and plots were assigned to each of these zones. Zones and the fumigant Telone had a significant effect on soybean yield. The two zones with the lowest values for EC_a-dp (19-35 and 35-53 mS/m) showed a significant response with yield to Telone averaging an increase over the control of 20.3 and 11.4 bushels/acre, respectively. There was no yield response from Telone over the control with the three zones that ranged from 53-117 mS/m.

Mississippi (G. Lawrence, V. Klink):  Effect of Seed Treatments on Root-Knot Management for Soybean and Cotton (W. Adnan Aljaafri, G.W. Lawrence, V .P. Klink, D. H. Long and K. S. Lawrence). Biological control is being accepted as an alternative to chemicals methods. Experiments were conducted at Mississippi State University to determine the efficacy of potential biological control products for management of the root-knot nematode. Seed applied biological products were received from Albaugh, LLC. Cotton and soybean seeds were treated with nine and seventeen biological compounds, respectively. Seeds were planted in 500 cm³ of a steam sterilized sand: soil mix 10 cm Dia. clay pots and remained for 50 days. Each test included Abamectin and ILeVo as industry standards. Seed applied biological compounds significantly reduced root-knot nematode development on cotton and soybean. Seeds treated with Abamectin, and ALB-EXP5-1+ALB-SAR1 significantly reduced juvenile development and number of eggs produced on cotton. On soybean seeds treated with Abamectin and Bionematicide+thiabendazol+ALB-GG reduced root-knot juvenile development. Abamectin and SAR+Harpin protein+Thiabendazol reduced the number of eggs that developed on soybean roots. Seed applied biological products may have potential in nematode management.

 Performance of commercially available Gossypium hirsutum varieties grown in

Rotylenchulus reniformis infested soils with and without nematicides. (H. Randall Smith, G.W. Lawrence, R. Harkess, K.S. Lawrence, D.L. Lang, M. Phillips, P. Knight). Reniform nematode (Rotylenchulus reniformis Linford and Oliveira) infests 36% of Mississippi cotton (Gossypium hirsutum) acres promoting economic losses of $130 million annually.  Previously nematodes were managed using Temik 15G at-planting or fumigants, but with label loss of Temik 15G and expense of soil fumigants need arises to develop an integrated nematode management program  which entails understanding which commercial variety exhibit tolerance to R. reniformis since no resistance exists. Little tolerance to R. reniformis has been reported in G. hirsutum varieties, however, studies indicate some varieties perform better than others in R. reniformis infested soils.  Two field and greenhouse studies at Mississippi State University during 2012 indicated all evaluated variety growth parameters improved with a nematicide but some varieties grew and yielded better than others without nematicides.  Early plant growth parameters (plant height, plant height by node, vigor, hypocotyl length) in some varieties were less impacted without nematicide. Tolerance in untreated varieties was further observed in fruit retention during different growth stages especially at fruiting position one.  Untreated varieties did have lower fruit retention promoting harvest maturity loss, further displayed in greater number of nodes above cracked boll, lower percent open boll and greater boll diameter differences.  Some commercial varieties (Stv 5458 B2RF, FM 1740 B2RF and Phy 499 WRF) evaluated showed tolerance.  Greenhouse studies further validated field findings showing R. reniformis population increase related to reduced shoot and root growth with varying performance by variety.

Agricultural chemical companies and developmental products currently designed for nematode control in row and vegetable crops. Efficacy studies have been conducted in 2016 with the products listed in Table 1 to determine their effect on nematode infestations of field crops. Many are still in their early developmental stages therefore only numbers or codes are available for some of the listed products.

 Table 1. Experimental and Existing Nematicide Products examined in Mississippi by Company, Product and Application Method

Missouri (H. Nguyen):  Development of genetic markers and genotyping technology.

Two new single nucleotide polymorphism (SNP) markers were successfully developed and validated for the resistance genes of the Rhg1 locus. These markers coupled with the Kompetitive Allele Specific PCR (KASP) genotyping technology were able to effectively differentiate copy number variation (CNV) of the resistance genes among soybean genotypes studied. For instance, 8 copies can be detected for lines with PI 88788-type resistance, 3 copies for lines with Peking-type resistance, and 1 copy for lines with susceptibility. For the Rhg4 locus, two new SNP markers were also developed and validated for the resistance gene harbored at this locus. Between these two markers, one SNP was able to differentiate resistant lines with Peking-type Rhg4 from susceptible lines. For a novel QTL on Chr. 10 identified in PI 567516C and PI 567305, one KASP genotyping assay was developed and validated for this region. The development of SNPs and genotyping assays of the second QTL on Chr. 18 in these soybean germplasm are in progress.

These SNP markers along with the KASP genotyping assays were routinely utilized for marker-assisted selection to support the North Central Soybean Research Program’s advanced breeding lines and the soybean breeding programs of the University of Missouri (MU), in an effort to accelerate the improved germplasm and variety development.

Breeding and germplasm development: In 2015, in collaboration with Dr. Grover Shannon, MU, 97 advanced breeding lines of both conventional (CONV) and roundup ready (RR) soybeans were evaluated for five races of SCN (PA-1, -2, -3, -5, and -14). Of these, 46 lines showed resistance to one or more races and 10 lines showed resistance to four or more races of SCN. These lines were also evaluated for RKN in Dr. Li Lab, University of Georgia, and for RN in Dr. Robbins Lab, University of Arkansas. Of these, 15 lines (MGs E. IV to Mid. V) that performed well in the 2015 Southern Missouri Yield Tests have been entered the 2016 Regional Uniform Tests-Southern States. These tests selected 14 breeding lines with resistance to all three nematode species, SCN, RKN, and RN.

In addition to resistance to multi-nematode pests, several breeding lines of CONV or RR soybeans were also evaluated for resistance to frogeye leaf spot (FLS) or tolerance to salinity. Of these, many lines were released as new germplasm/varieties or licensed to a commercial company to sale to mid-south soybean growers. For instance, line S12-3791 and S11-3782 were resistant SCN, RKN and FLS; line S11-9618RR2 was resistant SCN, RKN, FLS, and tolerant to salinity; S11-15857 was resistant to all three nematode species. Three CONV lines, S11-16653, S11-17025, S11-20124, and two RR lines, S11-20195RR1 and S11-20337RR1, were resistant to three nematodes. The new varieties were increased for seeds and are anticipated to be released late 2016 with broad commercialization in 2017.

North Carolina (E. Davis, C. Opperman, D. Bird):  The compound spirotetramat (Movento^TM, Bayer CropScience, Inc) was originally developed as an insecticide but has shown activity against nematodes in multiple studies.  Spirotetramat functions as a lip synthesis inhibitor and has two-way systemic movement in plants.  The purified active enol-form of spirotetramat metabolized within plants was shown to arrest the development of Caenorhabditis elegans in lab assays without acute toxicity, but not reduce egg hatch rates of C. elegans, Meloidogyne incognita, or Heterodera glycines at any rate tested.  Applications of Movento at the labeled rate for nematodes to foliage of host plants prior to or at the time of nematode inoculation had minimal affects on development and reproductive rates of M. incognita in tomato or H. glycines in soybean plants.  Significant, but not complete, reduction in M. incognita and H. glycines female development and reproduction were observed with Movento application at 1-2 weeks post-inoculation of plants, consistent with a role of spirotetramat affects in arresting nematode development.

North Carolina researchers also investigated the development of new delivery methods of abamectin to target plant nematodes in soil.  Non-viable nanoparticles of the red clover necrotic mosaic virus (RCNMV) had been developed for delivery of chemicals to various targets, and the delivery of abamectin through the soil root zone was increased through the use of the virus nanoparticles.  A second method of abamectin delivery for root crop seed pieces utilizes impregnation of a unique cellulose matrix with the compound to wrap root pieces (ie. tubers) to protect emerging roots from nematode damage.

Texas (T. Wheeler):  There is some concern that populations of Meloidogyne incognita may be developing, that can partially overcome resistance genes in cotton.  In work conducted in nine field trials during 2011 – 2013, partially resistant cultivars (1-gene resistance) significantly reduced root-knot nematode density 70 % relative to a susceptible check cultivar in all fields.  From 2013 to 2016, in 15 field trials, average root-knot nematode density on partially resistant cultivars was reduced by 49% compared to susceptible check cultivars.  The two-gene, root-knot nematode resistant cultivars by Deltapine and Phytogen averaged 14% and 9% (i.e. reduced by 86 to 91%) respectively, root-knot nematode population densities relative to susceptible check cultivars during 2013 - 2016.

Three cultivars (Phytogen [PHY] 499WRF {susceptible}, Fibermax [FM] 1944GLB2 (replaced in 2016 by NexGen 3406B2XF {susceptible}), and Stoneville [ST] 4946GLB2 {partially resistant}), were treated with either Velum Total at 14 oz/acre in the furrow at planting, or with Vydate CLV with 17 oz/acre banded, twice at the 3-leaf stage and one week later.  Treatments were evaluated for root galling, root-knot nematode density, and yield.  Velum Total did reduce overall root-knot nematode galls/root in some fields.  Nematicides generally did not affect root-knot nematode density measured in late August.  Vydate CLV did improve yields, even with the partially resistant cultivar, in some cases, and gave a more consistent yield response than did Velum Total.  There is some concern that effectiveness of Velum Total could be highly dependent on good soil moisture conditions (like rainfall or irrigation) soon after planting.  This is continuing to be evaluated. 

With declining irrigation pumping capacity in the Southern High Plains, many producers are choosing to plant wheat in the fall after cotton harvest, and then fallow the land the following year after the wheat is harvested.  The effects of this rotation were compared with continuous cotton, when root-knot nematode resistant cultivars and three irrigation rates were also incorporated into the management program.  Between 2013 and 2016, root-knot nematode fall population density was reduced by 49 to 84% for the wheat/cotton rotation compared with continuous cotton, depending on irrigation rate. Cotton yields (2013 – 2015) following the wheat/fallow rotation averaged 40 to 50% higher, depending on irrigation rate, than continuous cotton.  Yield benefits are likely due to both reduction in root-knot nematodes, but also to better soil properties.

Virginia (C. Johnson):  Host Resistance: Twenty-one tobacco entries were transplanted into root knot nematode –infested soil in an on-farm nematode resistance experiment near Palmer Springs, VA. Galling on 1 November was lowest on breeding line XHN60 and flue-cured tobacco cultivar CC13. Galling was also significantly lower on XHN65, CC33, CC35, XHN72, XHN73, CC37, XHN67, PVH2275, PVH2310, CC65, XHN71, XHN58, PVH1452, T-15-1-1, NC925, and Coker 371-Gold compared to that on CC1063. Galling was not significantly lower (statistically) on GL395 and NC196 to that on CC1063. However, no resistance to root-knot biotypes other than M. incognita races 1 and 3 is claimed for PVH2310, CC65, PVH1452, NC925, and Coker 371-Gold.

A graduate student (Mr. Noah Adamo) also began a doctoral research project in 2016 to investigate resistance in tobacco to other species and races of Meloidogyne. Mr. Adamo’s program will have seek to clarify the resistance and/or tolerance characteristics of T15-1-1 (possessing the Rk2 gene) alone, and in combination with Rk2, to M. arenaria (race 1 and/or 2), M. incognita (race 1 and/or 2 and/or 4), and/or M. javanica; to better understand the mechanism(s) of resistance to root-knot nematodes imparted by Rk2 alone and/or combined with Rk1; to determine the resistance and/or tolerance characteristics of tobacco breeding lines 81%-617A and BAG29-15-3-32-1 to root-knot nematodes; and to establish F5 mapping populations including ~180 families from a cross of susceptible standard cultivar Hicks with T15-1-1 for eventual phenotyping and genotyping. F4 plants are currently being maintained at the Southern Piedmont AREC to advance these families.

Cultural Tactics: Preparations were initiate in 2016 for experiments to evaluate use of crops such as sun hemp, pearl millet, sorghum, and Brassica juncea (Caliente 199) as cover crops to reduce population densities of G. t. solanacearum (TCN). A 1 acre field at the Southern Piedmont AREC was planted with a susceptible tobacco cultivar in 2016 to produce uniform initial TCN population densities for a 2017 experiment. Brassica juncea will be seeded during fall 2016 in several high tunnels at the same research station to facilitate future testing as well.

2016 Field Survey: 2004 and 2010 surveys sampled fields in numerous counties and farms within counties to better understand the distribution of plant-parasitic nematodes in tobacco fields in Southside (South Central) Virginia. Our 2016 survey focuses on multiple fields being managed by a smaller number of farmers, aiming to clarify the scale of nematode management factors facing tobacco growers. Samples are still being collected, but as of now 5 farms have been sampled, primarily from Pittsylvania county, but also 1 farm in Halifax county. Twenty-five were sampled from the Halifax county farm, that we already know has Meloidogyne and Globodera populations in some fields.  Four to 8 fields were also sampled from each of 4 other farms in Pittsylvania county.

Nematode Management Agent (NMA) Evaluation:  Root-Knot Nematodes: Although galling was observed at the end of the 2016 growing season, initial population densities of Meloidogyne spp. were very low in a 2016 on-farm root-knot nematode resistance test. Pre-treatment populations of Pratylenchus were observed in a minority of experimental units, as well as ectoparasitic species such as stunt and spiral nematodes. Nematode control was evaluated after transplant water application of 17.7 fl oz/A of Velum Total; transplant water use of 6.6 fl oz/A Luna Privilege alone or followed by 6.4 fl oz of Luna Privilege/A at layby (~ 4 weeks later); pre-plant incorporation of 1.9 pt/A Nimitz as a 12” band centered over where the transplanting furrow would be; and application of Majestene at 0.9 or 1.9 gal/A as a transplant water treatment followed by over-the-top incorporated sprays at the first cultivation (~2 weeks after transplanting) and at layby, in comparison to a non-treated control and application of 30.5 fl oz Vydate C-LV/A in the transplant water and at the first cultivation.  Data was collected on nematode population densities, plant growth, root galling, and final fresh weight of leaves. No differences were observed among treatments in subjective ratings of vigor and uniformity (0-5) on 22 June or 7 July; in root galling on 8 July and 1 November; in plant height or number of leaves on 8 July; or in leaf fresh weight on 8 July or 5 October.

Tobacco Cyst Nematode (TCN - Globodera tabacum solanacearum):  Initial TCN population densities were high, averaging over 12,000 eggs/500 cm³ of soil, and large numbers of TCN juveniles were observed in plant roots ~6 weeks after transplanting. Juvenile numbers in tobacco roots at that time were lowest where Luna Privilege (fluopyram), Telone II (1,3-dichloropropene), Velum Total (fluopyram + imidacloprid), IRF 266 (66% allyl isothiocyanate + 33% chloropicrin) or high rates of Majestene (heat-killed Burkholderia spp. strain A396 cells and spent fermentation media) had been applied. Leaf fresh weight ~6 weeks after transplanting was significantly higher than in the untreated control plots where 20 gal/A of IRF 266, 17 fl.oz./A of Velum Total, 10 gal/A of Telone II, 2.8 or 3.7 pt/A of Nimitz (fluensulfone), or two applications of 6-7 fl.oz./A Luna Privilege had been applied. Plant vigor ratings (0-5) 55 days after transplanting were significantly higher for most treatments compared to the untreated control, but were highest for 20 gal/A and 8 gal/A of IRF 266, 10 gal/A of Telone II, two applications of 6-7 fl.oz./A of Luna Privilege or 8-10 fl.oz./A of Velum Total, or a single transplant water application of 17 fl.oz./A of Velum Total. The percentage of plants topped within 75 days of transplanting was highest (and greater than in the untreated control) for 10 gal/A of Telone II, 12-20 gal/A of IRF 266, Velum Total applied at 17 fl.oz./A at transplanting or applied at 8 fl.oz./A at transplanting and again at 10 fl.oz./A at the last cultivation (layby).

Journal Articles:

Bhandari, B., G. O. Myers, M. O. Indest, and C. Overstreet. 2015. Response of five resistant cotton genotypes to isolates of Rotylenchulus reniformis collected from reniform infested fields in Louisiana. Nematropica 45:252-262.

Bird, D. M., Jones, J. T., Opperman, C. H., Kikuchi, T., & Danchin, E. G. 2015. Signatures of adaptation to plant parasitism in nematode genomes. Parasitology 142:S71-S84.

Burke, M., Scholl, E. H., Bird, D. M., Schaff, J. E., Coleman, S., Crowell, R., Diener, S., Gordon, O., Graham, S., Wang, X., Windham, E., Wright, G. & Opperman, C. H.  2015. The plant parasite Pratylenchus coffeae carries a minimal nematode genome. Nematology 17:621-637.

Cao, J., Guenther, R. H., Sit, T. L., Lommel, S. A., Opperman, C. H., & Willoughby, J. A. 2015.  Development of abamectin loaded lignocellulosic matrices for the controlled release of nematicide for crop protection. Cellulose doi :10.1007/s10570-015-0817-6.

Cao, J., Guenther, R. H., Sit, T. L., Lommel, S. A., Opperman, C. H., & Willoughby, J. A. 2015. Development of abamectin loaded plant virus nanoparticles for efficacious plant parasitic nematode control. Small 10(24):5126-5136.

J.D. Eisenback, L. S. Graney, and P. Vieira. 2016. First report of the apple root-knot nematode, Meloidogyne mali, in North America found parasitizing Euonymus in New York. Plant Disease 100(9): November 2016.

Kadam S, Vuong TD, Qiu D, Meinhardt C, Wang J, Li Z, Shannon JG, and Nguyen HT . 2016. Genomic-assisted phylogenetic analysis and marker development for next generation soybean cyst nematode resistance breeding. Plant Sci. 242: 342–350.

Khanal, C., A. L. Szalanski, and R. T. Robbins. 2016.  First report of Meloidogyne partityla parasitizing pecan in Arkansas and confirmation of Quercus stellate as a host. Nematropica 46:1-7.

Kim KS, D. Qiu, T.D. Vuong, R.T. Robbins, J.G. Shannon, Z. Li, H.T. Nguyen. 2016. Advancements in breeding, genetics, and genomics for resistance to three nematode species in soybean. Theor. Appl. Genet. DOI 10.1007/s00122-016-2816.

Klink VP. 2016. Plastic embedding tissue for laser microdissection-assisted developmental genomics analyses at single cell resolution. Medical Research Archives 4:1-12.

Land, C. J., K. S. Lawrence, and M. Newman. 2016. First Report of Verticillium dahliae on Cotton in Alabama. Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849. Plant Dis. 100:1, 2016; published online as http://dx.doi.org/10.1094/PDIS-10-15-1143-PDN.

Lee JD, Kim HJ, Robbins RT, Wrather JA, Bond J, Nguyen HT, and Shannon JG. 2015. Reaction of Soybean Cyst Nematode Resistant Plant Introductions to Root-Knot and Reniform Nematodes. Plant Breed. Biotech. 3(4):346–354.

Lin J, Mazarei M, Zhao N, Hatcher CN, Wuddineh WA, Rudis M, Tschaplinski TJ, Pantalone VR, Arelli PR, Hewezi T, Chen F, Stewart CN Jr (2016). Transgenic soybean overexpressing GmSAMT1 exhibits resistance to multiple-HG types of soybean cyst nematode Heterodera glycines. Plant Biotechnology Journal, 14: 2100-2109.

Noon, J.B., Hewezi, T.A.F., Maier, T.R., Simmons, C., Wei, J.Z., Wu, Gusui, Llaca, V., Deschamps, S., Davis, E., Mitchum, M., Hussey, R.S., Baum, T.J. 2015. Eighteen new candidate effectors of the phytonematode Heterodera glycines produced specifically in the secretory esophageal gland cells during parasitism. Phytopathology 105-1362-1372.

Noon JB, Qi M, Sill DN, Muppirala U, Eves-van den Akker S, Maier TR, Dobbs D, Mitchum MG, Hewezi T, Baum TJ (2016). A Plasmodium-like virulence effector of the soybean cyst nematode suppresses plant innate immunity. New Phytologist, 212: 444-460.

Pant SR, McNeece BT, Sharma K, Nirula PM, Burson HE, Lawrence GW, Klink VP. 2016a. The heterologous expression of a Glycine max homolog of NONEXPRESSOR OF PR1 (NPR1) and a-hydroxynitrile glucosidase suppresses parasitism by the root pathogen Meloidogyne incognita in Gossypium hirsutum. Journal of Plant Interactions 11:41-52

Paulo Vieira, Kathryn Kamo, and Jonathan D. Eisenback. 2016. Plant-mediated silencing of a fatty acid- and retinoid-binding Pp-far-1 gene can reduce Pratylenchus penetrans propagation. Plant Pathology

Plaisance, A. R., E. C. McGawley, and C. Overstreet. 2015. Influence of plant-parasitic nematodes on growth of St. Augustine and centipede turfgrass. Nematropica 45:288-296.

Pollok, J.A., C.S. Johnson, J.D. Eisenback, and T.D. Reed. 2016. Reproduction of Meloidogyne incognita race 3 on flue-cured tobacco homozygous for Rk1 and/or Rk2 resistance genes. Journal of Nematology 48(2):79-86.

Pollok, Jill R., Charles S. Johnson, J. D. Eisenback, and T. David Reed. 2016. Reproduction of M. incognita race 3 on flue-cured tobacco homozygous for Rk1 and/or Rk2 resistance genes. Journal of Nematology.

Sharma K, Pant SR, McNeece BT, Nirula PM, Burson HE, Lawrence GW, Klink VP. 2016b.  Co-regulation of the Glycine max soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE)-containing regulon occurs during defense to a root pathogen. Journal of Plant Interactions 11:74-93.

Szitenberg, A., Cha, S., Opperman, C.H., Bird, D.M., Blaxter, M., and Lunt, D.H. 2015.  Purifying selection and drift, not life history or RNAi, determine transposable element evolution. BioRxiv doi: http://dx.doi.org/10.1101/034884.

Vang, L.E., Opperman, C.H., Schwarz, M.R., Davis, E.L. 2016. Spirotetramat causes an arrest of nematode juvenile development. Nematology 18:121-131.

Vieira, Paulo, Joseph Mowery, James Kilcrease, Jonathan Eisenback and Kathyrn Kamo. 2016. Histological characterization of Lilium longiflorum cv. 'Nellie White' infection with root lesion nematode, Pratylenchus penetrans. Journal of Nematology

Vuong, T.D., H. Sonah, R. Deshmukh, S. Kadam, C.G. Meinhardt, R. Nelson, J.G. Shannon, and H.T. Nguyen. 2015. Genetic architecture of cyst nematode resistance revealed by genome-wide association study in soybean. BMC Genomics (16) 593-604.

Whitham SA, Qi M, Innes RW, Ma W, Lopes-Caitar V, Hewezi T (2016). Molecular soybean-    pathogen interactions. Annual Review of Phytopathology, 54:443-468.   

 Xiang, Ni and K. S. Lawrence. 2016. Optimization of In Vitro Techniques for Distinguishing between Live and Dead Second Stage Juveniles of Heterodera glycines and Meloidogyne incognita. PLOS ONE: http://dx.doi.org/10.1371/journal.pone.0154818

Book Chapter:

Faske, T. R.  2016. Root-Knot Nematode.  Pp. 95-96 in D. Mueller, K. Wise, A Sisson, D. Smith, E. Sikora C. Bradley and A. Robinson. A Farmer’s Guide to Soybean Diseases.  S. Paul: APS Press

Published Abstracts:

Eisenback, J. D.  2016. Making megapixel mosaic micrographs of microscopic nematodes. Society of Invertebrate Pathology. July 24-28. Tours, France

Eisenback, J. D. 2016.  Morphological and molecular techniques for the diagnosis of nematodes.  National Plant Disease Diagnostic Network 4th Annual Meeting. March 7-11. Washington, D.C.        

Eisenback, J. D. 2016. Project Nematoda: a collection of all original descriptions of nematodes. Society of Nematologists, July 17-21. Montreal, Canada

Gill Giese, Ciro Velasco-Cruz, Lucas Roberts, and Jon Eisenback. 2016. Ten years of complete vineyard floor cover crops: Effects on nematode populatons and vegetative parameters of Cabernet Sauvignon. American Society of Enology and Viticulture, July 18-21. St. Louis, MO

Godoy, F.M.C., C. Overstreet, E.C. McGawley, D. M. Xavier and M.T Kularathna. 2016. A survey of Aphelenchoides besseyi on rice in Louisiana. Proceedings of the joint meeting of the Society of Nematologists and the Organization of Nematologists of Tropical America. Abstract. p. 92.

Johnson, C.S. 2016. Potential new nematode management agents for tobacco production in Virginia. Joint Meeting of the Society of Nematologists and the Organization of Nematologists of Tropical America, Montreal, Canada. July 17, 2016.

Johnson, C.S. 2016. Managing tobacco nematodes using isothiocyanate products. CORESTA Congress, Berlin, Germany. October 10, 2016.

Khanal, C., E. C. McGawley and C. Overstreet. Assessment of geographic isolates of endemic populations of Rotylenchulus reniformis against selected cotton germplasm lines. Proceedings of the joint meeting of the Society of Nematologists and the Organization of Nematologists of Tropical America. Abstract. p. 115.

Kularathna, M. T., C. Overstreet, E.C. McGawley, D. M. Xavier and F. M. C. Godoy. 2016. Impact of Fumigation on soybean varieties against Rotylenchulus reniformis. Proceedings of the joint meeting of the Society of Nematologists and the Organization of Nematologists of Tropical America. Abstract. p. 121.

Xavier-Mis, D., F. M. C. Godoy, C. Overstreet and E.C. McGawley. 2016. Susceptibility of grain sorghum cultivars to Meloidogyne incognita isolates from Louisiana. Proceedings of the joint meeting of the Society of Nematologists and the Organization of Nematologists of Tropical America. Abstract. p. 195.

 Ma, Xinyuan, P. Agudelo, E. Bernard, C.M. Holguin and R.T. Robbins. 2016. Hoplolaimus Smokyi  N. SP. (Hoplolaimidae), A Lance Nematode from the Great Smoky Mountains. 2016. Program and Abstracts, 55^th Annual Meeting of the Society  of Nematologists, Montreal Canada.

 McGawley, E.C., C. Overstreet and A. M. Skantar. 2016. Enhanced awareness of nematology: educational materials, extension activities and social media. 2016. Proceedings of the joint meeting of the Society of Nematologists and the Organization of Nematologists of Tropical America. Abstract. p. 135.

McInnes, B., M. M. T. Kularathna, E.C. McGawley and C. Overstreet. 2016. Evaluation of endemic populations of Rotylenchulus reniformis within Louisiana on soybean genotypes with known levels of resistance to soybean cyst nematode. Proceedings of the joint meeting of the Society of Nematologists and the Organization of Nematologists of Tropical America. Abstract. p. 136.

 Paulo Vieira, J. Mowery, J. Kilcrease, J. D. Eisenback, and K. Kamo. 2016. Cytologivcal changes of Easter lilly (Lillium longiflorum) upon root lesion nematode (Pratylenchus penetrans) infection. USDA-ARS Poster Day, Belstville, Md., June 4, 2016.

Paulo Vieira, Joseph Mowery, James Kilcrease, Jonathan D. Eisenback and Kathryn Kamo. 2016. Histological characterization of Lilium longiflorum infection by Pratylenchus penetrans, using bright- field and transmission electron microscopy. European Society of Nematologists, Aug. 28-Sept.1, Braga, Portugal.

Paulo Vieira, Sarah Wantoch, J. D. Eisenback, and Kathryn Kamo. 2016. Identification of nematode target genes for root lesion nematode control.  USDA-ARS Poster Day, Belstville, Md., June 4, 2016.

Paulo Vieira, T. Maier, I. A. Zasada, T. Baum, K. Kamo, and J. D. Eisenback.  2016. Data mining of the root lesion nematode (Pratylenchus penetrans) transcriptome for identification of candidate effector genes. Society of Nematologists, Montreal, Canada July 18-21.

Paulo Vieira, Thomas Maier, Inga A. Zasada, Thomas Baum, Kathryn Kamo and Jonathan D. Eisenback. 2016. Identification of parasitism-related genes in Pratylenchus penetrans. European Society of Nematologists, Aug. 28-Sept.1, Braga, Portugal.

Proceedings:

 Allen, T. W., Bradley, C. A., Damicone, J. P., Dufault, N. S., Faske, T. R., Hollier, C. A., Isakeit, T., Kemerait, R. C., Kleczewski, N. M., Koenning, S. R., Mehl, H. L., Mueller, J. D., Overstreet, C., Price, P. P., Sikora, E. J., Spurlock, T.N., and Young, H. 2016.  Southern United States Soybean Disease Loss Estimates for 2015.  Proceedings of the Southern Soybean Disease Workers Annual Meeting; March 9-10; Pensacola, FL. Pp. 11-16.

 Burns, D., and C. Overstreet. 2016. On farm evaluation of nematode resistant cotton varieties. Proceedings of the 2016 Beltwide Cotton Conference; 5-7 January, 2016; New Orleans, LA. National Cotton Council, Cordova, TN. Pp. 806-810.

 Dodge, D., and K. Lawrence. 2016. Combination effect of commercial starter fertilizers, plant hormones and nematicides on soybean growth and pest management of Meloidogyne incognita. Proceedings of the 2016 Beltwide Conference Vol. 1: 577-580. National Cotton Council of America, Memphis, TN.

Eisenback, J.D. and P. Vieira. 2016. IMP Lab Innovation report on surveys of vegetables and rice nematodes in Cambodia. Virginia Tech, Blacksburg, VA

Groover, W., and K. Lawrence. 2016. Diagnostic identification of Meloidogyne species to expedite pathogen detection in row crops. Proceedings of the 2016 Beltwide Conference Vol. 1: 574-576. National Cotton Council of America, Memphis, TN.

Haygood, R., C. Overstreet, J. Woodard, T. Spurlock, and M. Lovelace. 2016. Advances in precision placement of Telone II soil fumigant for management of nematodes. Proceedings of the 2016 Beltwide Cotton Conference; 5-7 January, 2016; New Orleans, LA. National Cotton Council, Cordova, TN. Pp. 123-125.

Lawrence, K., A. Hagan, M. Olsen, T. Faske, R. Hutmacher, J. Mueller, D. Wright, R. Kemerait, C. Overstreet, P. Price, G. Lawrence, T. Allen, S. Atwell, S. Thomas, N. Goldberg, K. Edmisten, R. Bowman, H. Young, J. Woodward,and H. Mehl. 2016. Cotton disease loss estimate committee report, 2015. Proceedings of the 2016 Beltwide Cotton Conference Vol. 1: 113-115. National Cotton Council of America, Memphis, TN.

Lawrence, K., G. Lawrence, T. Faske, R. Kemerait, C. Overstreet, T. Wheeler, H. Young, and H. Mehl. 2016. Beltwide nematode research and education committee 2015 nematode research report cotton varietal and nematicide responses in nematode soils. Proceedings of the 2016 Beltwide Conference Vol 1: 737-740. National Cotton Council of America, Memphis, TN.

Luangkhot, J, and K. Lawrence. 2016. Growth hormone and starter fertilizer effects on root-knot population suppression and cotton yield enhancement when combined with Velum total or Vydate CLV. Proceedings of the 2016 Beltwide Conference Vol 1: 719-727. National Cotton Council of America, Memphis, TN.

Robbins, R. T., P. Chen, G. Shannon, S. Kantartzi, Z. Li, T. Faske, J. Vellie, L. Jackson, E. Gbur, and D. Dombek. 2016. Reniform nematode reproduction on soybean cultivars and breeding lines in 2015, Proceeding of the 2016 Beltwide Cotton Conferences, New Orleans Pg 131-143.

Rothrock, C., S. Winters, T. W. Allen, J. D. Barham, A. B. Beach, M. B. Bayles, P. D. Colyer, H. M. Kelly, R. C. Kemerait, G. W. Lawrence, K. Lawrence, H. L. Mehl, P. Price, and J. Woodward. 2016. Report of the cottonseed treatment committee for 2015. Proceedings of the 2016 Beltwide Cotton Conference Vol. 1: 117-122. National Cotton Council of America, Memphis, TN.

Rothrock, C., T. Allen, H. Kelly, R. Kemerait, G. Lawrence, K. Lawrence, H. Mehl, R. Norton, P. Price, and J. Woodward. 2016. Impact of seedling diseases and Pre-emergence herbicides on cotton stand establishment and plant development. Proceedings of the 2016 Beltwide Conference Vol 1: 741-742. National Cotton Council of America, Memphis, TN.

Smith, H. R., G. W. Lawrence, R. L. Harkess, K. S. Lawrence, D. J. Lang, J. M. Phillips, and P. R. Knight. 2016. Effects of nematicide seed treatments with and without foliar applications of Vydate-CLV on the growth and development of G. hirsutum grown in R. reniformis infested soils. Proceedings of the 2016 Beltwide Conference Vol 1: 781-797. National Cotton Council of America, Memphis, TN.

Smith, H. R., G. W. Lawrence, R. L. Harkess, K. S. Lawrence, D. J. Lang, J. M. Phillips, and P. R. Knight. 2016. Performance of commercial G. hirsutum varieties grown in R. reniformis infested soils with and without nematicides. Proceedings of the 2016 Beltwide Conference Vol 1: 743-761. National Cotton Council of America, Memphis, TN.

Till, S., K. Lawrence, K. Glass, and D. Schrimsher. 2016. Evaluation of cotton cultivars in the presence and absence of reniform nematode and the efficacy of Velum total. Proceedings of the 2016 Beltwide Conference Vol 1: 590-592. National Cotton Council of America, Memphis, TN.

Xiang, N., K. Lawrence, J. Kloepper, and J. McInroy. 2016. 2015 studies of plant growth promoting rhizobacteria for biological control of Meloidogyne incognita on cotton. Proceedings of the 2016 Beltwide Conference Vol 1: 586-589. National Cotton Council of America, Memphis, TN.

Plant Disease Management Reports:

Darnell, L., and C.S. Johnson. 2016. Evaluation of nematicides for control of tobacco cyst nematodes in Virginia, 2014. Plant Disease Management Reports 10:N005

Darnell, L., and C.S. Johnson. 2016. Evaluation of nematicides for control of tobacco cyst nematodes in Virginia, 2015. Plant Disease Management Reports 10:N004.

Dodge, D., and K. S. Lawrence. 2016. Nematicide and fungicide efficacy and yield comparison for management of root-knot nematode on soybean Alabama, 2015. Report No. 10:N008

Dodge, D., and K. S. Lawrence. 2016. Soybean variety yield comparison with and without Velum Total for management of root-knot nematode Alabama, 2015. Report No. 10:N007.

Faske, T. R., Emerson, M. and Hurd, K. 2016. Evaluation of cotton cultivars and nematicides for management of reniform nematode in Arkansas, 2014. PDMR 10: N013.

Faske, T. R., Emerson, M. and Hurd, K. 2016. Evaluation of cotton cultivars and nematicides for management of root-knot nematode in Arkansas, 2015. PDMR 10: N014.

Hurd, K., Faske, T. R., and M. Emerson 2016. Efficacy of Velum Total to manage root-knot nematode on cotton in Arkansas, 2015. PDMR 10: N021.

Hurd, K., Faske, T. R., and M. Emerson 2016. Evaluation of Velum Total and COPeO to manage root-knot nematode on cotton in Arkansas, 2015. PDMR 10: N020.

Hurd, K., Faske, T. R., and M. Emerson 2016. Evaluation of ILeVO at three rates for suppression of root-knot nematode in a greenhouse trial in Arkansas, 2015.PDMR 10: N016

Lawrence, K. S., C. J. Land, N. Xiang, J. Luangkhot, and C. Norris. 2016. Cotton variety and nematicide combinations for reniform management in north Alabama, 2015. Report No. 10:N010.

Lawrence, K. S., C. J. Land, N. Xiang, J. Luangkhot, and C. Norris. 2016. Velum Total in-furrow spray applications for reniform management in north Alabama, 2015. Report No. 10:N011.

Lawrence, K. S., C. J. Land, N. Xiang, J. Luangkhot, and C. Norris. 2016. Vydate CLV in-furrow spray applications for reniform management in north Alabama, 2015. Report No. 10:N012.

Lawrence, K. S., C. J. Land, N. Xiang, J. Luangkhot, and C. Norris. 2016. Fungicide combination evaluations for cotton seedling disease management in north Alabama, 2015. Report No. 10:FC012.

Lawrence, K. S., C. J. Land, N. Xiang, and J. Luangkhot. 2016. Cotton variety and nematicide combinations for root-knot nematode management in Alabama, 2015. Report No. 10:FC133.

Luangkhot, J., and K. S. Lawrence. 2016. In-furrow sprays on cotton to manage Southern root-knot nematode in Alabama, 2015. Report No. 10:N002.

Luangkhot, J., and K. S. Lawrence. 2016. Reniform nematode management utilizing variety selection with and without seed treatments in Alabama, 2015. Report No. 10:N001.

Till, S. R., and K. S. Lawrence. 2016. Fungicide seed treatments for control of Rhizoctonia solani in upland cotton in Alabama, 2015. Report No. 10:FC013.

Xiang, N., and K.S. Lawrence. 2016. Evaluation of the experimental compounds for the control of soybean SDS in North Alabama, 2015. Report No. 10:FC104.

Xiang, N., and K.S. Lawrence. 2016. Evaluation of the experimental compounds for the control of soybean SDS in central Alabama, 2015. Report No. 10:FC105.

Xiang, N., and K.S. Lawrence. 2016. Evaluation of the experimental compounds for soybean seedling disease management in North Alabama, 2015. Report No. 10:FC103.