Eight advanced durum-breeding lines were treated with 5-methyl-azacytidine to test the feasibility of generating sources of Fusarium head blight (FHB) resistance. Of the 800 treated seeds, 415 germinated and were advanced up to four (M4) generations by selfing. Thirty-two of the resulting 415 M4 lines were selected following preliminary screening and were further tested for FHB resistance for three years at two field locations, and in the greenhouse. Five of the 32 M4 lines showed less than 30% disease severity, as compared to the parental lines and susceptible checks. Fusarium-damaged kernels and deoxynivalenol analyses supported the findings of the field and greenhouse disease assessments. Two of the most resistant M4 lines were crossed to a susceptible parent, advanced to third generation (BC1:F3) and were tested for stability and inheritance of the resistance. About, one third of the BC1:F3 lines showed FHB resistance similar to their M4 parents. The overall methylation levels (%) were compared using FASTmC method, which did not show a significant difference between M4 and parental lines. However, transcriptome analysis of one M4 line revealed significant number of differentially expressed genes related to biosynthesis of secondary metabolites, MAPK signaling, photosynthesis, starch and sucrose metabolism, plant hormone signal transduction and plant-pathogen interaction pathways, which may have helped in improved FHB resistance.
Bibliographical noteFunding Information:
Funding for the project was provided by the U.S. Department of Agriculture, Agricultural Research Service, under Agreement No. 58-3640-3-008, and the Minnesota State Agricultural Experiment Station. This is a cooperative project with the U.S. Wheat and Barley Scab Initiative. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture. We thank Drs. Yanhong Dong (University of Minnesota) for assistance in DON analysis, Robert J Schmitz, University of Georgia and Katie Liberatore (Caylaxt inc.) for assistance in methyl-ome analysis, and Marisa Miller (Pairwise Genomics) for assistance in transcriptome analysis. We thank Roger Casper (USDA-ARS Cereal Disease Lab) and Amar Elakkad (University of Minnesota) for excellent technical and field assistance. Mention of trade names or commercial products in this publication is solely for purpose of providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture. USDA is an equal opportunity provider and employer.