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. Oomycetes including Pythium and Phytophthora continue to cause significant damage on a number of economically important vegetable, fruit, ornamental, and row crops in North America and around the world. Members of this multistate research project have continued to provide new insight into the genetic diversity of a number of oomycete pathogens in a variety of production systems. New genetic resources and many new molecular markers were developed for the soilborne vegetable pathogen Phytophthora capsici. The genetic resources include genomic DNA re-sequencing data for 18 P. capsici isolates recovered from locations worldwide and RNA sequencing data for 35 isolates of P. capsici at two time-points in the infection process of tomato (24 and 72 hours). These resources provided the raw material to identify widely distributed and conserved polymorphic single nucleotide polymorphism (SNP) positions in the genome and to develop genotyping assays to assess genetic diversity in populations worldwide. Ongoing analyses of oomycetes baited from Tennessee streams and rivers (predominantly Phytophthora and Pythium) have identified species known to be pathogens of economically important nursery and forest plants. Further research on oomycete pathogens have focused on assessing of genetic diversity of Phytopthora infestans inoculum in Andean soils. This work was presented in two B.S. Biotechnology Engineering dissertations written by two undergraduate students from the Universidad de las Fuerzas Armadas ESPE who graduated in Summer 2013 in collaboration with researchers at Oklahoma State University. In related work by researchers at OSU, the multi-locus phylogenetic analysis of the P. irregulare complex was conducted confirming the species status of P. cryptoirregulare and P. vipa. Additionally, the characterization of Pythium isolates collected from ornamental greenhouses in Long Island, NY in 2012 and 2013 by molecular barcoding (ITS) was completed. Current research is focused on the temporal dynamics analysis of these isolates, to understand seasonal changes in Pythium populations in ornamental operations. In related work taking place at Oregon State University a new project funded by the Floriculture and Nursery Research Initiative (FNRI) to be developed in a collaborative agreement between NWREC-OSU and USDA-ARS Horticultural Crops Research Laboratory in Corvallis, will identify and characterize the most prevalent soilborne plant pathogens, including Phytophthora, Pythium, and Verticillium affecting commercial nursery production systems; develop novel and rapid assays to detect the most prevalent soilborne pathogens; and characterization of the roles of soil fungal communities in nutrient cycling and soil health. Work in Minnesota has also focused on understanding the diversity of Pythium species present in crop soils. Pythium species were surveyed using two different methods for collection of isolates. The two methods differed considerably in their efficiency. In one survey Pythium species were obtained by baiting soil samples collected from 32 locations in Minnesota where stand establishment had been a problem. Only five species were identified in this survey. Pythium irregulare, Pythium recalcitrans, and Pythium ultimum were the predominant species. A related survey for Pythium species was conducted by isolating from symptomatic plants collected in the field. In this survey 30 Pythium species were isolated. The most common species found were Pythium ultimum, Pythium heterothallicum, Pythium sylvaticum, and Pythium oopapillum. In both surveys Pythium species were identified and identity confirmed using morphological and molecular techniques. The isolates collected are being screened for pathogenicity on both corn and soybean. Other research activities involved Verticillium dahliae, a fungal species that causes vascular wilt diseases on over 400 host plants. Monocotyledonous crops have been traditionally considered to be non-hosts of V. dahliae, and cereal species have been used in crop rotations as a cultural measure for the management of Verticillium wilts by reducing the amount and/or efficiency of pathogen inoculum, but have had limited or inconsistent success. However, we found that the fungus can establish endophytic relationships with oat plants grown as rotational crops. A population genetics approach using microsatellite markers revealed that the populations from symptomatic and asymptomatic hosts were significantly different. While at least five distinct genotypes were differentiated in the V. dahliae populations obtained from potato, only one of the genotypes was consistently found associated with oats, in different sampling years and grown in different fields. Populations of V. dahliae isolated from two potato cultivars that vary in their response to Verticillium wilt (cvs. Reba and Snowden) were also different, and diversity seemed to be positively correlated with susceptibility to the disease; that is, more diversity in the highly susceptible cultivar, less in the moderately resistant. In a related project being conducted 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 of V. dahliae 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 (1 that infects strawberry and 1 that infects mint) was initiated. Sequencing was completed at the University of New Hampshire on an Illumina HiSeq 2500. The first assemblies have been completed and we have just started the first comparative analyses against the reference V. dahliae strain, which was recovered from lettuce. 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 to 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 submitted for publication in Plant Disease. Current work has begun to focus on the genetic diversity of R. solani infecting soybean and drybean 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. Related research on Rhizoctonia spp. conducted in the southern U.S. has characterized the spatial distribution of Rhizoctonia spp. in fields undergoing rice and soybean rotation in Arkansas. Rhizoctonia aerial blight of soybean is a disease caused by Rhizoctonia solani AG1-IA. This pathogen also causes sheath blight of rice. Populations and disease assessments were characterized in producers' fields on a spatial scale to represent the topography of the field intermittent of the rice levee positions. Directional distribution ellipses for distribution of R. solani AG1-IA using soil and plant samples indicated agreement with drainage. Across years, distribution of R. solani AG1-IA appears to be controlled by levee position. Where levees do not form logical areas of collection, the greatest concentration of inoculum appears to be in the lower elevations of the field. The spatial distribution of the early-season inoculum of R. solani AG1-IA reiterates the idea that inoculum in the form of sclerotia and hyphae associated with rice residue floating and collecting at lower points within the levees. Aerial blight was observed in NE Arkansas in 2013, spatial assessments of incidence of aerial blight and the height up the soybean plant at GPS positions intermittent the levee system validated models indicating the highest amount of disease was in the logical areas of collection (a combination of levee position and elevation). Because the disease occurred in a similar distribution as the inoculum, a predictive model using geographically weighted regression analysis is being constructed for fields with no prior disease assessment. In these fields, elevation data has been provided by USGS (LiDAR) and levee data provided by the grower. Using a quantitative determination of levee bends (m/m2), prediction based on random assignment of geospatially tagged points should allow for the use of handheld GPS devices to guide scouting to areas with the highest likelihood of inoculum collection and aerial blight development. In 2013, 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. While evidence suggests it is weakly pathogenic on rice and soybean no noticeable damage or yield loss was observed. Because prior years' work had determined that R. solani AG11 was associated with areas of greater plant stand, experiments are currently in progress to determine its role in the rice/ soybean system and the potential benefit colonization of soybean may provide. R. solani AG1-IA also was observed causing aerial blight of peanut in Arkansas. Currently, there is a renewed interest in peanut production in the state and production practices include irrigation and various rotation schemes with soybean and less frequently rice. Thus, this may be an important disease of peanut in Arkansas. 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. A project established in Iowa is examining 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. Researchers are currently doing soil moisture retention curves, and have collected three plant residues (corn, soybean, and alfalfa), dried, ground, and are characterizing them for mineral elements and organics components (lignin, cellulose, and hemicellulose). Dr. Loynachan's group is working with an Iowa company (Hecheng Global, Inc.) and its President (David F. Clark) to laboratory test a Chinese product claimed to enhanced the speed of breakdown of crop residues. His group has obtained the APHIS permit to import these organisms for laboratory testing and are awaiting their arrival. Research at The University of Tennessee' West Tennessee Research and Education Center evaluated the effects of potash application, four seed treatment supplements, and in-furrow applications of liquid calcium nitrate fertilizer on snap bean diseases, seedling emergence, plant stand, plant growth, and yield in two experiments in a field naturally infested with several soil-borne plant pathogens. In a test planted April 23, seedling emergence 15 days after planting was greatest when a standard seed treatment (thiamethoxam + mefenoxam + fludioxonil) received a calcium-containing supplement (Treatment A). The number of healthy plants per row was highest when the standard seed treatment was supplemented with Treatment A, particularly in plots receiving muriate of potash. Pathogens isolated from diseased seedlings during this experiment were tentatively identified as Fusarium spp. (60%), Macrophomina phaseolina (17%), Sclerotinia sclerotiorum (6%), and Rhizoctonia solani (5%). Snap bean yield was highest when the standard seed treatment was supplemented (Treatment A). The seed treatment supplements had no effects on seedling vigor, plant height, or plant flowering. In a snap bean test planted August 2, seedling emergence 5 and 7 days after planting was significantly delayed with application of muriate of potash at 100 lb/K2O per acre. Four calcium-containing seed treatment supplements had no effect on seedling emergence. Supplementing the standard snap bean seed treatment with a high rate of another experimental treatment (Treatment E) increased the number of healthy plants per row 2 weeks after planting while a lower rate increased the number of healthy plants 5 weeks after planting. Potash application increased the number of plants lost to seedling diseases by over 56%, decreased plant height by 5%, and decreased snap bean yield by 45%. The seed treatment supplements failed to significantly affect plant height or snap bean yield. Macrophomina phaseolina was isolated from 96% of the diseased plants. In a soybean field experiment, four rates of an in-furrow calcium nitrate spray (0, 1, 2, and 3 lb N/acre) were evaluated with and without muriate of potash for their effects on soybean seedling diseases, plant growth, and yield of untreated soybean seed. Soybean yield was lowest in plots that received the 1 lb N/acre in-furrow spray plus potash fertilization. In a greenhouse planting, a root-knot resistant soybean cultivar had higher levels of calcium and silicon in the outer cell layers of lateral roots than a susceptible cultivar. F3 seed was collected from crosses of potential snap bean breeding lines with horizontal resistance to the seedling disease complex common in Tennessee snap bean growing areas. Research conducted at Texas A&M University focused on determining the impact of oilseed meals on soil microbial communities. In the first study, soil microbial community responses to amendments of a glucosinolate-containing brassicaceous oilseed meal (Brassica juncea, mustard), a non-glucosinolate-containing, nonbrassicaceous oilseed meal (Linum usitatissimum, flax), and a nonoilseed biomass (Sorghum bicolor, sorghum-sudangrass) were characterized using a 28-day time series of replicated 16S rRNA gene and fungal ITS gene sequence libraries. Distinct separation occurred by amendment type, with mustard inducing large increases in the abundance of bacterial taxa associated with fungal disease suppression (e.g. Bacillus, Pseudomonas, and Streptomyces spp.). Dramatic shifts were seen among the fungi, too, with phylotype richness decreasing by >60% following mustard addition. Changes in bacterial and fungal community composition were rapid, and distinct community types persisted throughout the study. The results from this study were published in 2013. In the second study, the effects of four types of isothiocyanates (ITCs), including allyl, butyl, phenyl, and benzyl ITC, on soil fungal and bacterial communities were determined. Each ITC was added to soil that also received 1% flax seedmeal (to represent organic material added by seedmeals). Microbial communities were analyzed based on the ITS gene for fungi and16S rRNA gene for bacteria using qPCR and tag-pyrosequencing with 454 GS FLX titanium technology. A dramatic decrease in fungal populations (~85% reduction) was observed after allyl ITC addition. Fungal community compositions also shifted following ITC amendments (e.g., Humicola increased in allyl and Mortierella in butyl ITC amendments). Bacterial populations were less impacted by ITCs with community compositions being primarily impacted by time of incubation. A manuscript based on these results was submitted for publication and is currently being revised based upon reviewer comments. Current research activities at Penn State University are directed towards beneficial microorganisms for improvement of important crops of the high Andes. Until May, this included both Ecuador and Bolivia, and since May, only Ecuador. With Ecuadorian researchers, we conducted a genetic survey of Peronospora variability on quinoa and its close relatives. This work resulted in a recently accepted article, and also a poster presentation on anthracnose in tree tomato. Similarly, 3 publications on seed borne pathogens of quinoa have appeared in the past 2 years, and point to the fact that live seed of quinoa sold in the U.S. for the food trade has imported exotic pathogens. These are relevant to the U.S. as quinoa is currently being developed as a new crop, particularly suited to the northwestern U.S. Experiments were established in Pennsylvania to measure plant and pathogen responses, as well as effects to plant tissue nutrient levels for faba bean and common bean. Significant responses have been recorded following application of plant growth promoting rhizobacteria, and/or the addition of phosphorus solubilizing bacteria. These data are currently being tabulated to adjust next year's treatment lists, and to confirm these results with validation trials in growth chambers. With Bolivian counterparts we have been developing sustainable farming practices for low-resource farmers. Plots evaluating numerous biological controls and organisms that enhance nutrient uptake have been established, and are being mirrored in the U.S. for severity of disease, nutrient sufficiency and for plant growth responses. Pennsylvania trials on faba bean, common bean and quinoa were conducted this summer. Plant samples sent to Pennsylvania from Bolivia were processed for beneficial plant-associated microbes, producing more than 300 distinct isolates that have been characterized for production of disease-suppressive antibiotics, phytohormone production, spore production, chitinase production, and phosphorus solubilization. They were also identified to species. We are continuing to evaluate this same pool of beneficial bacteria for effects on faba bean and common bean. An additional study was to isolate DNA from soil samples taken from raised bed farming systems near Lake Titicaca, that have produced sustainable crops for more than 500 years. Multiple members of the multistate research project continue to investigate better management strategies for the control of Pythium and the effect different chemical, biological and cultural management strategies have on Pythium community dyanmics. In Oregon an in vitro sensitivity test to determine fungicide resistance on three different species of Pythium (P. irregulare, P. sylvaticum, and P. ultimum) was completed. This research project was carried out in a cooperative agreement between USDA, Corvallis, and the North Willamette Research and Extension Center-Oregon State University, Aurora. A totoal of 119 Pythium isolates from forest nurseries in Oregon were tested for resistance to mefenoxam. Six different concentrations of the fungicide were evaluated. A paper with this data and additional data from evaluations with other fungicides was submitted for review in Plant Disease. Pythium is an ecologically diverse group of microorganisms found in virtually all soils, but little is known about the effect of crop rotation on Pythium communities. To understand the effect of crop rotation on species diversity, researcher in Arkansas collected soil from plots following a long-term rotation study including rice, corn, soybean and wheat. Soil from each plot was placed in cups, wetted to saturation, planted with the soybean cultivar Hutcheson, and incubated at 25°C. After 3 days, seeds were collected and washed in running water and placed on 2% water agar to bait out Pythium from soils. Molecular identification was performed by sequencing the ITS region and Blast analysis to a curated reference database. A total of 320 isolates were identified representing 12 species. Overall, the most frequently recovered species were P. spinosum, P. irregulare, P. pereocandrum and P. sylvaticum. In continuous rice production, P. spinosum was the most prevalent species isolated. In the soybean-wheat-rice and rice-wheat-soybean-wheat rotations, P. spinosum and P. irregulare were the most frequently recovered, while P. irregulare and P. sylvaticum were the most frequently recovered species in the soybean-rice and rice-soybean rotations. Pythium species composition reflected the frequency at which a susceptible host was planted in the rotation. In related research conducted at Oklahoma State University fungicide hormesis was assessed in vitro on Pythium irregulare, Sclerotinia homoeocarpa, and Botrytis cinerea, validating the stimulation of pathogen activity by low fungicide levels. A new M.S. student, Sumit Pradhan, evaluated a P. ultimum strain for hormetic responses to mefenoxam and 26 S. homoeocarpa isolates for biphasic dose-responses to thiophanate-methyl. Preliminary results on one P. irregulare and one S. homoeocarpa strains were reported at the 2013 APS Annual Meeting. A collaborative research project lead by researchers at Oklahoma State University focused on understanding the bacterial communities present in Andean soils from Ecuador, Chimborazo Province, suppressive to Phytophthora infestans, and was conducted using T-RFLP to assess the microbial diversity present in these soils. Bacteria corresponding to at least 13 phyla were identified. Most bacteria belonged to Actinobacteria, Proteobacteria and Firmicutes. Comparisons of suppression of Rhizoctonia solani and Phytophthora infestans between heat treated and non-treated soils suggest that bacteria of the genera Bacillus and Geobacillus are responsible of most of the suppressive nature of these soils. Screening for antifungal activity against Rhizoctonia solani and Phytophthora infestans of diverse bacterial strains from Andean soils was also completed and selected strains are being tested for biological control potential on potato foliage. Research conducted at Mississippi State University has focused on understanding genetics and biochemistry of soilborne and endophytic bacteria against plant pathogens. Objective 1 focused on identification of antagonistic bacteria associated with soilborne plant diseases. More than 800 bacterial isolates were obtained from soils and plant samples, and tested for antimicrobial activities using the standard bioassay procedures. Approximately 80 isolates showed significant antifungal activities against Geotrichum candidum and more than 40 isolates exhibited significant antibiotic activities against Erwinia amylovora. These isolates were further purified and preserved in a -80oC freezer. The isolates have been identified to be Bacillus spp., Pseudomonas spp., Burkholderia spp. and Streptomyces spp. using the 16S rDNA sequence analysis. Objective 2 was to investigate the genes associated with production of the antifungal compound occidiofungin produced by the soilborne bacterium Burkholderia contaminans strain M14. In collaboration with Dr. Jim Smith, we have characterized the functions of the ocfC and ocfN genes in antimicrobial activities. The third objective was to isolate endophytic bacteria associated with charcoal rot of soybean. 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 field where no symptoms of charcoal rot disease were evident. Plants were surface disinfected and split longitudinally with half of each plant used for isolation of fungal endophytes and half used for isolation of bacterial endophytes. Bacteria were isolated using an enrichment protocol with the majority retained for DNA sequencing and a fraction of each sample cultured on two media in different environments. Analysis of bacterial communities by isolation and Illumina sequencing is under way. In New Hampshire the first year of analyses of the fungal and bacteria communities associated with the forage crop perennial ryegrass were completed. The focus of this project has been to evaluate the effect of cultivar mixtures to extend the grazing season. A PhD student is evaluating the ability of these cultivar mixtures to recruit fungal symbionts while excluding pathogens. Soil has been collected from 4 sites in Maine, New Hampshire, Pennsylvannia, and Vermont. Extraction of DNA was successfully completed and he is now in the process of quantifying the fungal and bacterial biomass in each sample and preparing DNA libraries for Illumina sequencing of the 16S (bacteria) and 18S (fungi) for metagenomic analysis. Finally, the etiology of root rot caused by Fusarium solani is being investigated in Minnesota. The effects of F. solani on soybean plant germination and growth is influenced by fungal isolate, soybean cultivar, stage of plant development, soil temperature, and soil moisture. In general, soil inoculation with F. solani caused poor germination and reduced plant populations. However, plants that did germinate and flowered appeared to benefit from infection with greater root and above ground growth and greater seed yield. Research was conducted into the effects of inoculum methods and inoculum substrates infested with F. solani or F. virguliforme on disease symptom expression and plant growth. Management of this root rot fungus should emphasize control of its harmful effects on plant populations during seed germination. When investigating the etiology of F. solani, spurious symptoms, particularly lesion-like root discoloration and poor root development, were observed when many infested inoculum substrates such as seed of sorghum, rye, barley, or oats are used to inoculate soil during screening experiments. Inoculation with uninfested seed resulted in poor root development and decreased plant growth when compared to either plants root-inoculated with infested substrates or to an uninoculated control. The effect is dependent on species of plant seed used (most severe effects were seen when red sorghum was used as a substrate) but is also determined by the soybean cultivar planted. These effects are particularly relevant for evaluation of soybean cultivars and evaluation of pathogenicity of fungal isolates and can cause misleading symptoms unrelated to the effect of the pathogen.

Journal Artiicles: Abd-Elmagid A, Garrido PA, Hunger R, Lyles JL, Mansfield MA, Gugino BK, Smith DL, Melouk H, and Garzón CD. 2013. Discriminatory simplex and multiplex PCR for four species of the genus Sclerotinia. Journal of Microbiological Methods 91: 293-300. Akshaya Ravichandran, Ganyu Gu, Jerome Escano, Shi-En Lu, and Leif Smit,. 2013. The presence of two cyclase thioesterases expands the conformational freedom of the cyclic peptide occidiofungin. Journal of Natural Products 76:150-156. Arif M, Dobhal S, Garrido PA, Orquera GK, Espíndola AS, Young CA, Ochoa-Corona FM, Marek SM, Garzón CD. 2013. Sensitive and rapid detection of Phymatotrichopsis omnivora, causal fungus of cotton root rot. Plant Disease. Accepted. Canaday, C. H., 2013, Field evaluation of calcium supplements on soybean seedling diseases, emergence, plant stand, and yield, 2012. Plant Dis. Manag. Rep. 7:FC101. doi: 10.1094/PDMR07 Dayna Ellis, Akshaya Ravichandran, Gosai Jiten, Shi-En Lu, Donna Gordon and Leif Smith. 2013. The antifungal occidiofungin triggers an apoptotic mechanism of cell death in yeast. Journal of Natural Products 76:829-838. Demers JE, Garzón CD, and Jiménez-Gasco MM. 2013. Striking genetic similarity between races of Fusarium oxysporum f. sp. ciceris confirms a monophyletic origin and clonal evolution of the chickpea vascular wilt pathogen. European Journal of Plant Pathology. Accepted. Elmer, W.H., Useman, S., Schneider, R.W., Marra, R.E., LaMondia, J.A., Mendelssohn, I.A., Jiménez-Gasco, M. M., and Caruso, F.L. 2013. Sudden vegetation dieback in Atlantic and Gulf Coast salt marshes. Plant Disease 97: 436-445. Flores FJ and Garzón CD. 2013. Detection and assessment of chemical hormesis on the radial growth in vitro of oomycetes and fungal plant pathogens. Dose-Response 11: 361-373. Geiser, D.M., Akoi, T., Bacon, C.W., Baker, S.E., Bhattacharyya, M.K., Brandt, M.E., Brown, D. W., Burgess, L.W., Chulze, S., Coleman, J.J., Correll, J.C., Covert, S.F., Crous, P.W., Cuomo, C.A., De Hoog, G.S., Di Pietro, A., Elmer, W.H., Epstein, L., Frandsen, R.J.N., Freeman, S., Gagkaeva, T., Glenn, A.E., Gordon, T.R., Gregory, N.F., Hammond-Kosack, K.E., Hanson, L.E., Jiménez-Gasco, M.M., Kang, S., Kistler, H.C., Kuldau, G.A., Leslie, J.F., Logrieco, A., Lu, G., Lysøe, E., Ma, L.-J., McCormick, S.P., Migheli, Q., Moretti, A., Munaut, F., ODonnell, K., Pfenning, L., Ploetz, R.C., Proctor, R.H., Rehner, S.A., Robert, V.A.R.G., Rooney, A.P., Bin Salleh, B., Scandiani, M.M., Scauflaire, J., Short, D.P.G., Steenkamp, E., Suga, H., Summerell, B.A., Sutton, D.A., Thrane, U., Trail, F., Van Diepeningen, A., VanEtten, H.D., Viljoen, A., Waalwijk, C., Ward, T.J., Wingfield, M.J., Xu, J.-R., Yang, J.-B., Yli-Mattila, T., and Zhang, N. 2013. Letter to the Editor: One Fungus, One Name: Defining the genus Fusarium in a scientifically robust way that preserves longstanding use. Phytopathology 104: 400-408. Haddad, S., M. A. Tabatabai, and T. E. Loynachan. 2013. Biochemical processes controlling soil nitrogen mineralization under waterlogged conditions. Soil Sci. Soc. of Amer. 77:809-816. Hollister, E.B., P. Hu, A.S. Wang, F.M. Hons, and T.J. Gentry. 2013. Differential impacts of brassicaceous and non-brassicaceous oilseed meals on soil bacterial and fungal communities. FEMS Microbiol. Ecol. 83:632-641. Hu, J., Diao, Y., Lin, D., Bi, Y., Pang, Z., Fryxell, R. T., Liu, X. and Lamour, K. In Press. Loss of Heterozygosity drives clonal diversity of Phytophthora capsici in China. PLOS ONE. Hu, J., Pang, Z., Bi, Y., Shao., Diao, Y., Guo, J., Liu, Y., Lu, H., Lamour, K., and Liu, X. 2013. Genetically diverse long-lived clonal lineages of Phytophthora capsici from pepper in Gansu, China. Phytopathology, doi:10.1094/PHYTO-01-13-0016-R Kuan-Chih Chen, Akshaya Ravichandran, Adam Geurrero, Peng Deng, Sonya M. Baird, Leif Smith, and Shi-En Lu. 2013. The ocfC Burkholderia contaminans MS14 gene encodes a xylosyltransferase for the antifungal occidiofungin production. Applied and Environmental Microbiology 79:2899-2905. Lamour, K. and Hu, J. Diversity and Phytophthora: a threat to forests, crops and traditional laboratory research - Mini Review. CAB Reviews 8, No. 038. Malcolm, G. M., Kuldau, G. A., Gugino, B. K., and Jiménez-Gasco, M. M. 2013. Letter to the Editor: Hidden host plant associations of soilborne fungal pathogens: An ecological perspective. Phytopathology 103: 538-544. Remesal, E., Landa, B.B., Jiménez-Gasco, M.M. and Navas-Cortés, J.A. 2013. Sequence variation of protein-coding genes as a diagnostic tool for the identification of mycelial compatibility groups in Sclerotium rolfsii. Phytopathology 104: 479-487. 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