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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Publications at this Location » Publication #373594

Research Project: Genetic Enhancement of Sunflower Yield and Tolerance to Biotic Stress

Location: Sunflower and Plant Biology Research

Title: Genetic loci underlying quantitative resistance to necrotrophic pathogens Sclerotinia and Diaporthe (Phomopsis), and correlated resistance to both pathogens

item REINERT, STEPHAN - University Of Colorado
item POGODA, CLOE - University Of Colorado
item TALUKDER, ZAHIRUL - North Dakota State University
item ATTIA, ZIV - University Of Colorado
item COLLIER-ZANS, ERIN - University Of Colorado
item GULYA, THOMAS - Retired ARS Employee
item KANE, NOLAN - University Of Colorado
item Hulke, Brent

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/18/2020
Publication Date: 10/27/2020
Citation: Reinert, S., Pogoda, C.S., Talukder, Z.I., Attia, Z., Collier-Zans, E.C., Gulya, T.J., Kane, N.C., Hulke, B.S. 2020. Genetic loci underlying quantitative resistance to necrotrophic pathogens Sclerotinia and Diaporthe (Phomopsis), and correlated resistance to both pathogens. Theoretical and Applied Genetics.

Interpretive Summary: Phomopsis stem canker of sunflower and Sclerotinia head rot are the two most important disease issues in sunflower for humid production regions. They reduce confectionery sunflower seed quality and reduce oil yield and crop quality in oilseed sunflower. Previous research has indicated that a moderate correlation exists between resistance to these two diseases, which is good news for breeders as selection for resistance to one disease should increase resistance in the other. However, at this time, we do not know how this correlation relates to resistance genes on the genome of sunflower. The goal of this research was to find overlap between genes responsible for resistance to each disease. Fourteen head rot and 7 stem canker resistance markers were found, with one additional marker important for both diseases. In addition, we found that interaction between markers for both resistance traits exists, suggesting that there may be some common features in resistance to both diseases. This is useful information for breeders as they improve resistance to both important diseases, in sunflower and other plants.

Technical Abstract: 1) Necrotrophic pathogens can avoid or even benefit from plant defenses used against biotrophic pathogens, and thus represent a distinct challenge to plant populations in natural systems and in agriculture. Sclerotinia head rot and Phomopsis stem canker are two severe necrotrophic fungal diseases affecting domesticated sunflower. With no well-established methods to prevent infection in susceptible plants, host-plant resistance is preferred. 2) Despite knowledge of a moderate, positive correlation in resistance to the two diseases, analysis of the genetics, in the same or similar populations, has not been conducted. Here we present results of genome-wide analysis of resistance to both pathogens in a diversity panel of 218 domesticated genotypes. 3) We identified 14 head rot and 7 stem canker QTLs and observed extensive patterns of linkage disequilibrium between data sets and sites. In addition, there was evidence for one common locus that was significant in both data sets. 4) These results suggest there has been strong, simultaneous selection for resistance to these two diseases and that a general mechanism for defense against necrotrophic pathogens may exist.