Brief Summary of Minutes of Annual Meeting

1. Evaluate the population genetic diversity of soilborne pathogens and antagonistic microorganisms in different growing systems and regions using traditional and metagenomic approaches. In Minnesota, researchers aim to identify important seedling pathogens found in soybean and corn production fields, characterize etiology of disease development, determine species using traditional and molecular approaches, determine pathogenicity on corn and soybean, characterize sensitivity to commonly used seed treatment fungicides. Infection and lesion development caused by Fusarium solani was characterized microscopically. Infection occurred when lateral roots emerged through the root epidermis and simultaneously with lateral root development. Root lesions caused by F. solani originated at the point of lateral root primordium penetration through the epidermis and appeared to be enabled by disruption of the epidermis. Lesions then progressed both into the root cortex and laterally under the epidermis away from the emerging lateral root. The lesions were distinctive. Fields symptomatic for seed, seedling, or root rots in 22 Minnesota counties were sampled for Pythium species using one of two different methods. In the first method Pythium was isolated directly from symptomatic soybean seedlings collected in the field. In the second, soil from the field was collected, dried, and in the laboratory baited with soybean seeds. Isolates were identified using both morphological and molecular techniques. Thirty-four Pythium or Phytopythium species were found in samples from 13 counties. After collection, the pathogenicity of the most 18 common Pythium and Phytopythium species was tested at three different temperatures, 15, 20, and 25°C, on both soybean and corn seed using an in-vitro assay and on seedlings planted in growth media. A wide range of lesion development and root growth reduction was observed depending on the Pythium species and host plant. The effect of temperature on seed germination was dependent on Pythium species tested. For example P. intermedium was most damaging at 15°C while P. ultimum var sporangiferum and ultimum were more damaging on both corn and soybean at 25°C. P. conidiophorum, P. intermedium, P. irregulare, P. sylvaticum, and P. ultimum var sporangiforum and ultimum were most pathogenic on soybean. P. irregulare, P. sylvaticum, and P. ultimum var sporangiforum and ultimum also reduced corn seed germination. Pythium irregulare and P. ultimum var ultimum were pathogenic on developing soybean seedlings. The data show that some of the most common Pythium species found in Minnesota, including P. ultimum and P. sylvaticum, are detrimental to germination and growth of both corn and soybean. In addition Pythium seedling damage could be caused by Pythium spp. at either 15 or 25°C. In Tennessee, researchers developed novel genomic resources, including hundreds of new SNP markers for the downy mildew of spinach (Peronospora farinosa), the late blight of potato and tomato (Phytophthora infestans) and the fungal pathogen Cercospora sojina which causes frogeye leaf spot. The work with the markers and organisms is ongoing. In Mississippi, research focused on understanding genetics and biochemistry of soilborne and endophytic bacteria against plants pathogens. More than 200 bacterial isolates were obtained from soils and plant samples, and tested for antimicrobial activities using standard bioassay procedures. Approximately 60 isolates showed significant antifungal activities against Geotrichum candidum and more than 20 isolates exhibited significant antibiotic activities against Erwinia amylovora. These isolates were further purified and preserved at -80°C. The isolates were preliminarily identified to be Bacillus spp., Burkholderia spp. and Pseudomonas spp. using 16S rDNA sequence analysis. The genes associated with production of the antibacterial compounds synthesized by the bacterium Burkholderia contaminans strain M14 and Pseudomonas sp. strain YL23 were investigated. The two genes associated with antibacterial activities of strain MS14 have been identified, which encode a LuxR regulatory protein and a nonribosomal peptide synthase. secG is predicted to code a transporter protein and is required for antibiotic activities of Pseudomonas sp. YL23 against Erwinia amylovora and Dickeya chrysanthemi. The pqqC gene is essential for antifungal activity of Pseudomonas kilonensis JX22 against Fusarium oxysporum. Draft genome sequences of the bacteria Pseudomonas sp. YL23 and Burkholderia pyrrocinia strain Lyc2 were completed and published. Some useful gene clusters have been identified from the genome sequence drafts and the sequence data provide important insights into understanding antimicrobial activities of the bacteria. To understand the interaction between rice and the bacterial pathogen, the causative agent of bacterial panicle blight, transcriptomic analyses using next-generation sequencing and bioinformatics were conducted to identify differentially expressed transcripts between resistant and susceptible interactions and formulate a model for rice resistance to the disease. A few gene candidates were identified, which may be associated with plant resistance to the bacteria. The emergence and spread of Verticillium wilt was recently observed in cotton plants at the R.R. Foil Plant Science Research Center at Mississippi State during the summer of 2013 and 2014. This disease could pose a considerable threat to cotton growers because some breeding lines appeared to be extremely susceptible to the disease. Two soilborne fungi with different morphology and growth characteristics were isolated from diseased cotton plants by culturing infected stem tissues on potato dextrose agar (PDA) plates. The two fungi species were identified as Verticillium sp. and Diaporthe phaseolorum via ribosomal ITS DNA sequencing. Two ITS regions, ITS1 (between the 18S rRNA and 5.8S rRNA) and ITS2 (between 5.8S rRNA and 28S rRNA), are present in the fungal rRNA operon. The two ITS regions are removed during pre-rRNA cleavage. The isolated Verticillium sp. could be Verticillium dahliae, Verticillium longisporum or Verticillium albo-atrum and will be further identified using a PCR-based genotyping method with species-specific primers. In Arkansas, The spatial distribution of Rhizoctonia spp. in fields undergoing rice and soybean rotations was characterized in two producer fields in 2014 with the goal of management of R. solani AG1-IA, the cause of aerial blight on soybean and sheath blight on rice. In 2014, spatial sampling of soybean plants further confirmed Rhizoctonia solani AG11 as the most populous Rhizoctonia spp. in fields undergoing rice and soybean rotations in Arkansas. Colonization of soybean plants at the three-leaf stage were greater than 15% of the plants near Dumas and 37% of plants near Wiener, Arkansas. Isolates of R. solani were almost exclusively AG-11 at both sites. Application of the fungicide azoxystrobin limited the increase in colonization of soybean plants by R. solani compared to points not sprayed. The research reinforces the idea that populations of R. solani in soil colonize crops within the field and are dominated by populations that are not considered pathogenic. In New Hampshire, a number of cover crops species were screened to determine whether they harbor asymptomatic infections by the soilborne pathogen V. dahliae. To date we have found that many cover crop species including buckwheat, crimson clover, and winter rye are capable of harboring the fungus, but display no visual symptoms of infection. Only through the use of a strain of V. dahliae that expresses the green fluorescent protein (GFP), was the extensive colonization able to be visualized. Screening of both the commercial strawberry and one of its wild ancestors, Fragaria vesca, for resistance to V. dahliae with the GFP strain is currently in progress. One of the major obstacles in screening for resistance to soilborne root and wilt pathogens is that visual assessment does not provide an accurate assessment of fungal colonization or host resistance. Therefore two new methods are being evaluated for their ability to dissect resistance, tolerance, and susceptibility. Confocal microscopy using the GFP strain of V. dahliae is being used to measure colonization of susceptible, tolerant (visually healthy but ingress of fungal hyphae present), and resistant (visually healthy no ingress of fungal hyphae) strawberry cultivar. In addition, multispectral and thermal imaging systems are being evaluated for their ability to detect pre-visual stress as a potential phenotyping method. This process was initiated in the past year and protocols for inoculum production, inoculation, and visualization by confocal microscopy have all been standardized and screening of strawberry cultivars with known levels of resistance and susceptibility is in progress. Finally, the sequencing of two strains of V. dahliae (2 that infect strawberry and 1 that infects mint) was completed. The first assemblies have been completed and the comparative analyses against the reference V. dahliae strain, which was recovered from lettuce, have been completed. An additional 12 strains of V. dahliae from other host including tomato, potato, pistachio and the soil were included in the analysis. Preliminary analyses indicate that the isolate from strawberry recovered in California is more closely related to lettuce than the strawberry isolated recovered in New Hampshire. In addition the isolate from mint recovered in Oregon grouped together with the strawberry and lettuce strains from California but still differed at over 16,000 SNPs. Preliminary synteny analysis also indicate significant genomic rearrangement both within chromosome and between chromosomes. Future work will focus on identifying transposable element that may be responsible for the genome rearrangements. Research on sweetpotato tip/end rot is focused on defining and evaluating the pathogen(s) associated with this disease problem that was severe and widespread in 2009, but can still be found at high levels following harvesting. An initial study (Phase 1) was established in 2009 to determine the causal agents associated with tip/end rot and completed in 2013. Due to the thousands of isolates collected from traditional culturing, the identifications are now completed. During 2012 it was determined that reniform nematode, Rotylenchulus reniformis, levels were increasing in many fields from a general survey and was suspected that they might form a disease complex resulting in greater tip/end rot in Mississippi. Research was established in 2013 to evaluate those interactions with the most common pathogen isolated, Macrophomina phaseolina and reniform nematode using different populations in the field and in the greenhouse (Phase 2). Lastly, several projects have continued to evaluate the genetic diversity of R. solani from a number of important crop species across North America. Researchers at the University of New Hampshire in collaboration with the University of Guelph conducted a phylogenetic comparison of isolates of R. solani collected from canola and wheat growing region of western Canada. A total of 128 multinucleate isolates were identified by ITS sequence and compared with anastomosis group (AG) results. The multinucleate isolates of R. solani were grouped into 8 distinct clades. Two distinct clades were observed for isolates classified as AG2-1 by anastomosis testing, and isolates in a closely related clade to AG2-1 did not successfully fuse with any of the tester strains. While most isolates of AG-5 clustered together according to ITS sequences, three isolates classified by anastomosis grouping as AG-5 grouped with AG2-1, AG-4, and binucleate Rhizoctonia in the phylogenetic analysis. There was no genetic diversity among isolates classified as AG-4. While in most instances the results from AG tests were consistent with ITS sequence, there were several cases where isolates were inconsistently classified or failed to undergo anastomosis with any of the tester strains. In addition, a previously undocumented AG group was identified, and the AG-5 tester strain was found to form hyphal fusions with unrelated groups of multinucleate and binucleate species of Rhizoctonia. Results from this project were published in Plant Disease. Current work has begun to focus on the genetic diversity of R. solani infecting soybean and dry bean in northern regions with a specific focus on AG2-2. Early results indicate that isolates of R. solani AG2-2 may have as many as six distinct ITS sequences in a single strain. These finding raise a number of questions regarding the frequency at which members of AG2-2 anastomose in the wild and how genetically distinct they need to be before they can no longer anastomose. Objective 2. Examine the effect of traditional or newly developed management strategies (chemical, cultural, and biological), soil physicochemical properties, or introduced biological control agents on the microbial community and its ability to suppress soilborne pathogens An Iowa project is evaluating a Chinese product claimed to enhance the speed of breakdown of crop residues. The work was coordinated with an Iowa company hoping to market the product in the US. The objectives of the study were to quantitatively measure the efficacy of the product in decomposing plant residue. Corn residue and a Typic Hapludoll soil were characterized for essential elements (C, N, P, K, and pH). Residues were chopped and mixed with the soil in individual mesocosms (air-tight jars with NaOH vials to the collect carbon dioxide evolved); soil moisture was kept at field capacity and temperature at 25°C.Treatments were as follows: (1) no soil, no residue, no product (control), (2) soil, no residue, no product (3) soil, residue, no product, (4) soil, no residue, product, (5) soil, residue, product, and (6) soil, residue, sterilized product. After data analysis, it was determined there were no significant differences among treatments. We concluded that the product does not affect the rate of residue decomposition breakdown when the residue is chopped into small pieces and mixed with a warm, moist soil. Further work is planned for surface-applied residues and residues not finely chopped into smaller pieces. In Arkansas, Meloidogyne incognita, the root-knot nematode, and Thielaviopsis basicola, the cause of black root rot, and their interaction on cotton were examined for soil textures that ranged from 48 to 87% sand in microplots. Each soil texture was infested with 0, 4, or 8 M. incognita eggs and 0 or 20 T. basicola chlamydospore chains per gram of soil. Plant growth was suppressed early in the season and midseason by T. basicola and M. incognita suppressed plant growth and delayed plant development late in the season across all soil textures. Cotton yield was lower in the presence of either T. basicola or M. incognita. An interaction between M. incognita and T. basicola, which decreased plant growth and yield, occurred in one year when neither pathogen alone caused substantial plant damage. Root colonization by T. basicola and fungal reproduction and survival decreased in soil having 87% sand. M. incognita generally caused more galling and reproduction in soils as sand content increased. Root galling severity and M. incognita reproduction were suppressed by the presence of T. basicola in soil at sand contents lower than 87%. Soil texture had a greater impact on T. basicola than on M. incognita in this study. The findings support work on T. basicola over a 10-year period in a texturally diverse cotton field near Portland, Arkansas, where populations were quantified at planting and harvest in 512 contiguous plots between 2001 and 2013. The objective was to determine the spatial distribution of T. basicola and if these distributions had changed over time. Data were subjected to exploratory spatial analysis and then rigorous spatial regression to determine the distribution and correlations for each sampling time. For each year sampled, the distributions of T. basicola were aggregated. In all years, a significant negative correlation existed between T. basicola and percent sand fraction and a significant positive correlation existed between the fungus and percent silt. Areas corresponding to the highest clay content also had the highest T. basicola populations. Over the time of the study, the spatial distribution of T. basicola was relatively stable and dependent on soil texture. Meloidogyne incognita and Rotylenchulus reniformis are economically important nematode species in cotton production. Evidence from 2001-2003, in a texturally diverse cotton field near Portland, Arkansas, suggested that populations of M. incognita had the greatest effect on yield in soils with greater sand content. Additionally, exhaustive nematode assays indicated R. reniformis was increasing in population and distribution in the field. Since that work, the field has continued to be planted in cotton until being planted in soybean in 2013. From the original 512 plots, nematode population densities were measured in the fall immediately after the crop was harvested in 2011 and 2013. Over the 10 year period, populations of M. incognita declined sharply while R. reniformis increased. Univariate Moran’s I indicated significantly aggregated distributions for both pathogens in all years except 2011, and trend surface models indicated Range values decreased for M. incognita but increased for R. reniformis prior to 2013. Bivariate exploratory spatial analysis and spatial regression indicated a significantly dispersed distribution and inverse relationship in 3 of 4 years and 2 of 4 years respectively confirming competition and displacement of M. incognita by R. reniformis. Neither R. reniformis nor M. incognita populations were directly related to yield loss across soil textures. The highest yield impact of nematode populations occurred in the sandier areas of the field indicating site specific management in these textural zones should have the greatest economic return. Pythium spp. are important seed and seedling disease pathogens of soybean in Arkansas. Resistance to seedling diseases caused by Pythium spp. has been identified in the soybean cultivar ‘Archer’. To characterize and genetically map this resistance to Pythium aphanidermatum, 84 F2:7 recombinant inbreed lines (RIL) from an ‘Archer’ X ‘Hutcheson‘ cross were evaluated for resistance to P. aphanidermatum by using seed plate and greenhouse assays. In the seed plate assay, germination ranged from 4 to 85% and, in the greenhouse assay, stands ranged from 21 to 94%. Archer and Hutcheson germination averaged 37 and 4%, and stands averaged 73 and 21% for the seed plate and greenhouse assays, respectively. Single nucleotide polymorphisms (SNP) analysis using a 6K SNP chip is being done to examine inheritance. In the Mississippi region, Soybean Charcoal Rot research with the following specific objectives was conducted; 1) Characterization of endophytic bacterial and fungal communities associated with the soybean-charcoal rot disease system using both culture-dependent and independent analyses; and 2) Investigation of the effects of inoculation of bacteria and/or fungi on disease development and soybean growth. Four pairs of diseased and asymptomatic plants were collected from patches of plants affected by charcoal rot in a soybean field in Leflore County near Sidon, MS. Four additional asymptomatic plants were collected from areas of the same field where no symptoms of charcoal rot disease were evident. Soil from the rhizosphere of only one plant had a plant parasitic nematode present at greater than threshold levels. Each plant was prepared for bacterial and fungal endophyte examination through a series of washing steps and longitudinal division of the plant. One half of the plant was processed for isolation of bacterial endophytes and the other half was used for isolation of fungal endophytes. Fungal endophytes were isolated from each plant part (root, stem, leaf) separately. Three sets of plates were prepared and incubated in the three different oxygen environments. Plates were incubated in the dark at 28oC for 48 to 72 hours, at which time emerged mycelium was subcultured onto sterile plates containing the appropriate medium and incubated in the same environment as the original isolation plate for approximately 10 days. Plates were initially grouped by morphological similarities (color, texture, pattern of growth, etc.). The ITS region was amplified using primers ITS1f and ITS4 and the amplified product sequenced. Identification of culturable fungal isolates has been completed from the 2013 field samples. The most commonly occurring species are Phoma sp., Penicillium chryseogenum, Diaporthe phaseolorum, Fusarium sp., Aspergillus flavus, Diaporthe sojae, Fusarium oxysporum, Trichoderma reesei, Hypocrea lixii, and Alternaria alternata. Continuing work includes the extraction of DNA from whole soybean plant tissues (plant DNA and DNA of associated microorganisms), followed by amplification of the ITS1 gene region of any fungi associated with these tissues. The reverse ITS primers (ITS4) used for this procedure contain unique barcodes, which will allow separation and distinction of any non-culturable species that are present within the plant tissue via Illumina whole-community sequencing. DNA extraction is currently underway and PCR required for identification of fungi using Illumina sequencing of ITS DNA. Sweetpotato Tip/End rot Research: Studies are ongoing to define and evaluate the pathogen(s) associated with this disease problem that was severe and widespread in 2009, but can still be found at high levels following harvesting. An initial study (Phase 1) was established in 2009 to determine the causal agents associated with tip/end rot and completed in 2013. Due to the thousands of isolates collected from traditional culturing, the identifications are now completed. During 2012 it was determined that reniform nematode, Rotylenchulus reniformis, levels were increasing in many fields from a general survey and was suspected that they might form a disease complex resulting in greater tip/end rot in Mississippi. Research was established in 2013 to evaluate those interactions with the most common pathogen isolated, Macrophomina phaseolina and reniform nematode using different populations in the field and in the greenhouse (Phase 2). Phase 1: Multivariate analysis was conducted on the fungal isolate population to determine species richness, evenness, and diversity. The relative species richness for each confirmed fungi was compared using PC-ORD multivariate analysis software. Results show a wide distribution of species across many management periods, but the harvest and post-harvest sampling periods show the greatest species richness over both years. A number of fungi, Macrophomina phaseolina, Aspergillus flavus, A. niger, A. tubingens, A. japonicus, and six species of Fusarium, were pathogenic in trials on disease-free sweetpotato root tissue. In addition, F. oxysporum and F. solani consistently produced necrotic lesions in root tissue. These two species accounted for nearly 70% of the overall isolates from early-season seed stock and bedding plant samples. Microbial populations in post-harvest tissues also differed in relative abundance from prior sampling dates. Macrophomina phaseolina increased to 27% occurrence and F. oxysporum and F. solani decreased to 15.5% isolation frequencies between 60 and 90 days post-harvest. The relative occurrence of each of the identified pathogens was also analyzed using PC-ORD. Fusarium species were the dominant pathogenic isolate recovered from plant tissues during early season sampling, but in harvest through post-harvest sampling, Macrophomina phaseolina became the dominant pathogenic fungi recovered from plant tissues. Phase 2: We have used data from year 1 of our ongoing study for 2013-14, funded by the USDA Specialty Crops Research Initiative grant, to clearly define the relationship between the organisms, categorize risks to sweet potato growers, and propose management strategies to minimize assessed risks. In both 2013 and 2014 growing seasons, two fields with known histories of high nematode densities were sampled using plots of 1/1000 acre. Treatments within each field site were based on reniform counts including low range and high range. Twelve replicate plots per treatment were established per location. Data collection included destructive sampling of plants within each of the small plots at intervals. Plant tissues collected during destructive sampling were examined for nematode damage and fungi from samples are being cultured on PDA. Identified fungi will be recorded and placed in long-term storage. Harvestable yield data will be collected for each plot at the end of the growth cycle when the field is harvested by the grower. In Tennessee, a provisional patent application for one or more seed treatment supplements for improved control of seedling diseases of snap bean, soybean, and other agricultural or horticultural crops was submitted. Research at the University of Tennessee’s West Tennessee Research and Education Center evaluated the effects 12 seed treatment supplements with four rates of potash fertilization for their effects on seedling diseases of soybean, plant growth, and soybean yield in a field naturally infested with several soil-borne plant pathogens. Pathogens isolated from diseased seedlings during this experiment were tentatively identified as Rhizoctonia solani (57%). Fusarium spp. (39%), and Macrophomina phaseolina (4%). Increasing the rate of potash fertilization increased seedling disease incidence and decreased seedling emergence, seedling vigor, plant stand, plant growth and height, and soybean yield. Adding a supplement to a common soybean seed treatment decreased the overall loss of plant stand and increased early flowering. Adding a seed treatment supplement to the common soybean seed treatment increased soybean yield by over 320 kg/ha. Energy-dispersive X-ray analyses of the outer cell layers of lateral roots of 6-day-old soybean seedlings grown from seed with a seed treatment supplement had higher levels of calcium + magnesium than seedlings grown without the supplement. Research conducted at Texas A&M University focused on determining the impact of oilseed meals on fungal community composition and Fusarium wilt of chili pepper. Soil was amended with various seed meals [Camelina sativa ‘Crantz’ (CAME), Brassica juncea ‘Pacific Gold’ (P), Sinapis alba cv. ‘IdaGold’(I) and PI (mixture of P and I with 1:1 ratio)], incubated for 25 days, and grown with chili pepper in pots for 35 days. Soil microbial populations were characterized using qPCR and pyrosequencing. Fungal abundance was significantly increased by CAME, P and PI amendments, but did not correspond to disease incidence. The seed meal amendments also affected the fungal community composition. Specifically, CAME enriched Mortierellales including the genus Mortierella, whose abundance was not correlated disease incidence. P and PI enriched Chaetomium, whose abundance was negatively correlated with disease incidence, and also inhibited Hypocreales, including the genus of Fusarium, whose abundance was positively correlated with disease incidence. A manuscript based on these results was submitted for publication.

Broders, K.D., Parker, M., and Boland G. J. 2014. Diversity of Rhizoctonia solani associated with canola and wheat in Alberta, Manitoba, and Saskatchewan. Plant Disease. 98:1695-1701. Canaday, C. H., 2014, Effects of experimental seed treatment supplements on seedling diseases of spring-planted snap bean, 2013, Plant Disease Management Reports 8:ST024. Canaday, C. H., 2014, Effects of potash and experimental seed treatment supplements on seedling diseases of summer-planted snap bean, 2013, Plant Disease Management Reports 8:ST025. Cochran, K.A., and Rothrock, C.S. 2015. Brassica green manure amendments for management of Rhizoctonia solani in two annual ornamental crops in the field. HortScience (accepted). Donald, P., K. Lawrence, T. Kirkpatrick, B.Kemerait, J. Bond, D. Herschman, C. Overstreet, A. Wrather, G. Lawrence, S. Koenning, P. Adugelo and C. Canaday. 2014. Occurrence, distribution, and impact of nematodes in soybean fields in the southern United States. Journal of Nematology 46(2):154. Jaraba, J., Rothrock, C. S., Kirkpatrick, T. L., and Brye, K. R. 2014. Soil texture influence on Meloidogyne incognita and Thielaviopsis basicola and their interaction on cotton. Plant Dis. 98:336-343. Jianhong Xu, Peng Deng, Kurt C. Showmaker, Hui Wang, Sonya M. Baird, and Shi-En Lu. 2014. The pqqC gene is essential for antifungal activity of Pseudomonas kilonensis JX22 against Fusarium oxysporum f. sp. lycopersici. FEMS Microbiology Letters 353(2):98-105. Kamoun S, Furzer O, Jones JD, Judelson HS, Ali GS, Dalio RJ, Roy SG, Schena L, Zambounis A, Panabières F, Cahill D, Ruocco M, Figueiredo A, Chen XR, Hulvey J, Stam R, Lamour K, Gijzen M, Tyler BM, Grünwald NJ, Mukhtar MS, Tomé DF, Tör M, Van den Ackerveken G, McDowell J, Daayf F, Fry WE, Lindqvist-Kreuze H, Meijer HJ, Petre B, Ristaino J, Yoshida K, Birch PR, Govers F. 2014. The Top 10 oomycete pathogens in molecular plant pathology. Molecular Plant Pathology doi: 10.1111/mpp.12190. Loynachan, T. E. 2013. Experience in teaching a distance agronomy soil-plant graduate course. 275-9 Agron. Abstracts, Madison. Magbanua V. Zenaida, Arick Mark, Buza Teresia, Hsu Chuan-Yu, Showmaker C Kurt, Chouvarine Philippe, Deng Peng, Peterson G. Daniel, Lu Shi-En. Transcriptomic dissection of the rice-Burkholderia glumae interaction. BMC Genomics 15:755; doi:10.1186/1471-2164-15-755. Sandesh Shrestha, Jian Hu, Rebecca Trout Fryxell, Joann Mudge and Kurt Lamour. 2014. SNP markers identify widely distributed clonal lineages of Phytophthora colocasiae in Vietnam, Hawaii, and Hainan Island, China. Mycologia (in press). Spurlock, T. N., Kirkpatrick, T. L., Rothrock, C. S., and Monfort, W. S. 2014. Displacement of Meloidogyne incognita by Rotylenchulus reniformis during a 10 year cotton monoculture and implications for site-specific management. Journal of Nematology 46:238 (Abstr.) Spurlock, T. N., Kirkpatrick, T. L., Rothrock, C. S., and Monfort S. 2014. Evaluation of methods to quantify populations of Rhizoctonia spp. in soil. Plant Dis. (accepted). Spurlock, T. N., Greer, A. M. Tolbert, A. C., Kirkpatrick, T. L., Rothrock, C. S., and Monfort S. 2014. Spatiotemporal distribution of Thielaviopsis basicola after a ten year cotton monoculture. Phytopathology 104(Suppl.):S3.113. Urrea, K. E., Rupe, J. C., Rothrock, C.S., and Chen, P. 2014. Characterization of soybean resistance to Pythium aphanidermatum. Phytopathology 104 (Suppl.):S3.121. Wang X-Q, Showmaker KC, Yu X-Q, Bi T, Hsu C-Y, Baird SM, Peterson DG, Li X-D, Lu S.-E. 2014. Draft genome sequence of Burkholderia pyrrocinia Lyc2, a biological control strain that can suppress multiple plant microbial pathogens. Genome Announcements 2(5):e00991-14. doi:10.1128/genomeA.00991-14. Yan Li, Gary W. Lawrence, Shi-En Lu, Clarissa Balbalian, and Vincent Klink. 2014. Quantitative field testing Heterodera glycines from metagenomic DNA samples isolated directly from soil under agronomic production. PLoS One. 9(2): e89887. doi:10.1371/ journal.pone.0089887. Youzhou Liu, Shi-En Lu, Sonya Baird, Junqing Qiao, and Yan Du. 2014. Draft genome sequence of Pseudomonas chlororaphis YL-1, a biocontrol strain suppressing plant microbial pathogens. Genome Announcements 2(1): e01225-13.