Location: Sunflower and Plant Biology Research
2021 Annual Report
Objectives
Coordinate the development of a Sclerotinia initiative for expanded research to control this devastating disease which affects canola, sunflowers, soybeans, edible dry beans, lentils, peas and other crops. Research should be coordinated with interested ARS, state, and industry cooperators and administered through specific cooperative agreements. Planning workshops and annual meetings involving interested parties will be organized throughout the funding period.
Approach
Exotic and emerging plant diseases pose severe problems throughout the United States. Their increasing importance may be attributed to the introduction of pathogens into new geographic regions; modification of the environment that favor diseases; change in crop management practices; genetic shifts in the pathogen population; and other processes that may give them a competitive advantage.
Progress Report
This report documents progress for cooperative research performed as part of the National Sclerotinia Initiative and involves researchers at several U.S. universities and USDA-ARS locations, in cooperation with USDA-ARS in Fargo, North Dakota.
Over the past year, a second replication of inoculated field trials to evaluate Sclerotinia basal stalk rot resistance of approximately 100 early generation interspecific hybrids of cultivated sunflower with wild annual sunflower species was completed. A third and final replication of these trials is ongoing. Additionally, basal stalk rot resistance levels were evaluated for approximately 300 early generation and advanced sunflower test-cross hybrids to assess resistance potential for new inbred lines under development. These data are being used to select germplasm for further development or potential public release. Using the Arabidopsis model system, the causal gene underlying a significant genetic association for Sclerotinia resistance was identified. Experiments confirmed that natural variation in the Arabidopsis transcriptional mediator complex subunit MED20A significantly affects Sclerotinia resistance and med20a knockout mutants are highly susceptible to infection.
Research plans-of-work were requested for the Fiscal Year 2021 funding cycle in December 2020. Over $1.8 million in requests from 22 potential projects were received, with approximately $1.66 million available for distribution to selected plans-of-work. Proposals were reviewed and ranked by a scientific review panel. The Initiative Steering Committee met and awarded funds to 19 projects, spanning the research priority areas of Germplasm Resources & Translational Genomics, Pathogen Biology & Mechanisms of Resistance, and Disease Management & Crop Production.
Accomplishments
1. An improved, greenhouse method to evaluate sunflower resistance to Sclerotinia basal stalk rot. Evaluation of sunflower resistance to Sclerotinia basal stalk rot in field trials is time consuming and offers limited resolution for identifying resistance. ARS scientists in Fargo, North Dakota, and colleagues at North Dakota State University and Iowa State University developed and validated a new method to evaluate basal stalk rot resistance. The new method is time- and space-efficient and allows for disease evaluations in a single year as compared to the need for multi-year, multi-location studies using inoculated field trials. Results from the new method were strongly correlated with field observations. This new method will assist breeders in their evaluation of sunflower genetic populations to improve the identification of genomic regions associated with resistance to basal stalk rot.
Review Publications
Chittem, K., Yajima, W.R., Goswami, R.S., del Rio Mendoza, L.E. 2020. Transcriptome analysis of the plant pathogen Sclerotinia sclerotiorum interaction with resistant and susceptible canola (Brassica napus) lines. PLoS ONE. 15(3):e0229844. https://doi.org/10.1371/journal.pone.0229844.
Everhart, S., Gambhir, N., Stam, R. 2020. Population genomics of filamentous plant pathogens—a brief overview of research questions, approaches, and pitfalls. Phytopathology. 111:12-22. https://doi.org/10.1094/PHYTO-11-20-0527-FI.
Gambhir, N., Kamvar, Z.N., Higgins, R., Amaradasa, B., Everhart, S.E. 2020. Spontaneous and fungicide-induced genomic variation in Sclerotinia sclerotiorum. Phytopathology. 111:160-169. https://doi.org/10.1094/PHYTO-10-20-0471-FI.
Kelly, J.D., Awale, H.E., Wiersma, A.T., Wright, E.M. 2020. Registration of 'Adams' black bean. Journal of Plant Registrations. 15:253-259. https://doi.org/10.1002/plr2.20063.
Kelly, J.D., Awale, H.E., Wiersma, A.T., Wright, E.M. 2021. Registration of 'Charro' pinto bean. Journal of Plant Registrations. 15:260-264. https://doi.org/10.1002/plr2.20071.
Kelly, J.D., Awale, H.D., Wiersma, A.T., Wright, E.M. 2020. Registration of 'Eiger' great northern bean. Journal of Plant Registrations. 15:271-277. https://doi.org/10.1002/plr2.20090.
Underwood, W., Misar, C.G., Block, C., Gulya, T.J., Talukder, Z., Hulke, B.S., Markell, S. 2020. A greenhouse method to evaluate sunflower quantitative resistance to basal stalk rot caused by Sclerotinia sclerotiorum. Plant Disease. 105:464-472. https://doi.org/10.1094/PDIS-08-19-1790-RE.
Talukder, Z.I., Underwood, W., Misar, C.G., Seiler, G.J., Liu, Y., Li, X., Cai, X., Qi, L. 2021. Unraveling the Sclerotinia basal stalk rot resistance derived from wild Helianthus argophyllus using a high-density SNP linkage map. Frontiers in Plant Science. https://doi.org/10.3389/fpls.2020.617920.
