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Zhang, Yishan

University of British Columbia

Fusarium graminearum, the predominant causal agent of Fusarium head blight (FHB) in cereal crops, impacts the Canadian wheat industry through reducing grade and yield, and seed contamination with mycotoxins. Depending on the type of mycotoxins produced by F. graminearum, strains can be classified into multiple chemotypes. 3-acetyl-deoxynivalenol (3ADON) and 15-acetyl-deoxynivalenol (15ADON) are the dominant chemotypes in North America. A highly virulent population of the 3ADON chemotype is becoming more prevalent in North America, compared to the historically dominant population which produces 15ADON, resulting in an increasing risk of FHB in the Canadian wheat growing regions. Therefore, decoding the genetic factors of aggressiveness and their evolution among field populations is crucial for studying the wheat-Fusarium interactions. This project aims to map quantitative trait loci (QTL) conferring aggressiveness in F. graminearum (Fg-QTL), using a bi-parental population Fg09 (n = 170) derived from a cross between a 15ADON isolate (Nit5) and a 3ADON isolate from Saskatchewan (SK1797). A high-density genetic map was constructed and aggressiveness on the durum cultivar Kronos was evaluated. Through pan-genome analysis of a Nested Association Mapping Population (FgNAM), previously constructed to reflect aggressiveness variations in North American field populations, an Fg-QTL was identified in a sub-telomeric co-occurring with a genomic region with high nucleotide diversity on chromosome 3. This Fg-QTL explained 8.18 % of the variance in the area under disease progress curve (AUDPC) values and contained 36 genes. Three candidate genes were detected as potentially associated with the observed phenotypic differences in aggressiveness, as they exclusively held nucleotide variants unique to high-aggressiveness strains. Two of the genes encode proteins with predicted functions, mic19 and FLA protein, provided promising targets for further validation of the genetic basis of F. graminearum aggressiveness on durum wheat.

Text

2024-02-05

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/87411

Plant Science

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/