1. Characterized the genes expressing plant cell wall-degrading enzymes in the genome of Fusarium virguliforme. The fungus F. virguliforme causes root rot and sudden death syndrome in soybean, both of which produce significant reductions in soybean yields each year. An ARS scientist at Urbana and collaborators showed that F. virguliforme produces a diverse set of cell wall-degrading enzymes, including several unique enzymes not reported in other plant pathogenic fungi. The enumeration of the specific types of cell wall-degrading enzymes produced by F. virguliforme will facilitate strategies to reduce the severity of root rot and sudden death syndrome by expressing proteins that inhibit specific cell wall-degrading enzymes in transgenic soybean plants.
2. Identified multiple phytotoxins produced by the fungus causing sudden death syndrome. Fusarium virguliforme, a soilborne fungal pathogen, causes soybean sudden death syndrome (SDS) by producing toxins in soybean roots that are translocated to leaves where they cause damaging foliar symptoms. ARS scientists at Urbana, IL and cooperators bioinformatically identified F. virguliforme toxin genes that when expressed in plants induced SDS foliar symptoms. The identification of F. virguliforme genes that produce phytotoxins provides important insights into the etiology of this economically important disease and molecular targets for its management.
3. Identified a locus for tolerance to Tobacco ringspot virus (TRSV) in soybean and predicted the sensitivities of soybean plant introductions to TRSV. Tobacco ringspot virus causes a problematic disease in soybean that so far has no management options. ARS scientists at Urbana, Illinois and collaborators identified a single locus on soybean chromosome 2 that was strongly associated with tolerance to TRSV infection and predicted the sensitivities of 18,955 accessions in the USDA soybean germplasm collection to TRSV based on genomic estimates. Because limited resistance is available to TRSV in the soybean gene pool, the identification of a locus for tolerance to TRSV infection provides a potentially valuable tool for management of this soybean disease.
4. Identified and molecularly characterized 49 previously undescribed viruses that infect fungal pathogens of soybean. Soybean provides essential nutrients for both humans and food animals, and is an important source of bioenergy. Each year, fungal diseases significantly reduce soybean yields and seed quality, but some fungal viruses reduce the ability of pathogenic fungi to induce disease. ARS scientists at Urbana and collaborators identified viruses that infect the fungi that cause five widely prevalent soybean diseases: anthracnose, charcoal rot, Phomopsis seed decay, Rhizoctonia root rot and Sclerotinia stem rot. Because some of the viruses reduced the virulence of their fungal hosts, these results widened the range and diversity of biological agents that can be used in the management of fungal diseases of soybean.
Helfenstein, J., Pawlowski, M.L., Hill, C., Stewart, J., Lagos-Kutz, D., Bowen, C.R., Frossard, E., Hartman, G.L. 2015. Zinc deficiency alters soybean susceptibility to pathogens and pests. Journal of Plant Nutrition and Soil Science. 178:896-903.
Kandal, Y.R., Haudenshield, J.S., Srour, A.Y., Islam, K.T., Fakhoury, A.M., Santos, P., Wang, J., Chilvers, M.I., Hartman, G.L., Malvick, D.K., Floyd, C.M., Mueller, D.S., Leandro, L. 2015. Multi-laboratory comparison of quantitative PCR assays for detection and quantification of Fusarium virguliforme from soybean roots and soil. Phytopathology. 105(12):1601-1611.
Hartman, G.L., Pawlowski, M.M., Chang, H., Hill, C.B. 2016. Successful technologies and approaches used to develop and manage resistance against crop diseases and pests. In: Macramootoo, C. editor. Emerging Technologies for Promoting Food Security. Sawston,Cambridge; Woodhead Publishing. p. 43-66.
Marzano, S.L., Domier, L.L. 2016. Novel mycoviruses discovered from metatranscriptomics survey of soybean phyllosphere phytobiomes. Virus Research. 213(2):332-342.
Bekal, S., Domier, L.L., Gonfa, B., Lakhssassi, N., Meksem, K., Lambert, K.N. 2015. A SNARE-like protein and biotin are implicated in soybean cyst nematode virulence. PLoS One. doi: 10.1371/journal.pone.0145601.
Harbach, C.J., Allen, T.W., Bowen, C.R., Davis, J.A., Hill, C.B., Leitman, M., Leonard, B.R., Mueller, D.S., Padgett, G.B., Phillips, X.A., Schneider, R.W., Sikora, E.J., Singh, A.K., Hartman, G.L. 2016. Delayed senescence in soybean: Terminology, research update, and survey results from growers. Plant Health Progress. 17:76-83.
Chang, H., Brown, P.J., Lipka, A.E., Domier, L.L., Hartman, G.L. 2016. Genome-wide association and genomic prediction identifies associated loci and predicts the sensitivity of Tobacco ringspot virus in soybean plant introduction. Biomed Central (BMC) Genomics. 17:153. doi:10.1186/s12864-12016-12487-12867.
Chang, H., Domier, L.L., Radwin, O., Yendrek, C., Hudson, M., Hartman, G.L. 2016. Identification of multiple phytotoxins produced by Fusarium virguliforme including a phytotoxic effector (FvNIS1) associated with soybean sudden death syndrome foliar symptoms. Molecular Plant-Microbe Interactions. 96:96-108.
Hartman, G.L., Bowen, C.R., Haudenshield, J.S., Fox, C.M., Cary, T.R., Diers, B.W. 2015. Evaluation of disease and pest damage on soybean cultivars released from 1923 through 2008 under field conditions in Central Illinois. Agronomy Journal. 107:2373-2380.
Hartman, G.L., Pawlowski, M.L., Herman, T.K., Eastburn, D.M. 2016. Organically grown soybean production in the USA: Constraints and management of pathogens and insect pests. Agronomy. 6(1):16. doi:10.3390/agronomy6010016.
Kelly, H.Y., Dufault, N.S., Walker, D.R., Isard, S.A., Schneider, R.W., Giesler, L.J., Wright, D.L., Marois, J.J., Hartman, G.L. 2015. From select agent to established pathogen: The response to Phakopsora pachyrhizi (soybean rust) in North America. Phytopathology. 105(7):905-916.
Pawlowski, M.L., Bowen, C.R., Hill, C.B., Hartman, G.L. 2016. Responses of soybean genotypes to pathogen infection after the application of elicitors. Crop Protection Journal. 87:78-84.
Rincker, K., Hartman, G.L., Diers, B.W. 2016. Fine mapping of resistance genes from five brown stem rot resistance sources in soybean. The Plant Genome. doi:10.3835/plantgenome2015.08.0063.
Weems, J.D., Haudenshield, J.S., Bond, J.P., Hartman, G.L., Ames, K.A., Bradely, C.A. 2015. Effect of fungicide seed treatments on Fusarium virguliforme infection of soybean and development of sudden death syndrome. Canadian Journal of Plant Pathology. 37:435-447.
Yang, H., Haudenshield, J.S., Hartman, G.L. 2015. Multiplex real-time PCR detection and differentiation of Colletotrichum species infecting soybean. Plant Disease. 99:1559-1568.
Chang, H., Yendrek, C.R., Caetano-Anolles, G., Hartman, G.L. 2016. Genomic characterization of plant cell wall degrading enzymes and in silico analysis of xylanses and polygalacturonases of Fusarium virguliforme. BMC Microbiology. 16:147. doi: 10.1186/s12866-016-0761-0.
Divilov, K., Walker, D.R. 2016. Reaction of Diaporthe longicolla to a strain of Sarocladium kiliense. Biocontrol Science and Technology. 26(7):938-950.