Wheat effector assisted breeding for resistance to fungal pathogens (WEAB)

BGPI : équipe 4National audienceThe discovery that fungal effector proteins are important for infection represents a novelopportunity for controlling plant diseases. Use of fungal effectors for resistance breeding is a game-changing technology creating opportunities and innovative methods to identify novel resistances tofungal diseases in plants. These methods are amenable to high throughput phenotyping. The recentavailability of high-density genetic marker coverage of the wheat genome allows the mapping ofnovel resistances identified through such high throughput phenotyping. We are using necrotrophicprotein effectors from Parastagonospora nodorum (Pn) and toxic proteins from Fusariumgraminearum (Fg) and Zymoseptoriatritici(Zt)to detectresistance genes/QTLsin wheat.Complementary strategies will be used to detect a large array of resistance mechanisms to fungaleffectors. Recombinant necrotrophic protein effectors and toxic proteins are produced in yeast andthe purified proteins are delivered into wheat leaves by syringe infiltration. Symptom development isscored few days after infiltration. Screening of 220 elite French wheat cultivars with Pn ToxA, 1 and 3has highlighted a large number of cultivars insensitive to the 3 necrotrophic effectors, and only a fewcultivars that were sensitive to all three effectors, suggesting that previous breeding for fieldresistance to Pn (1960-1980) led to the accumulation of insensitivity alleles. To validate thishypothesis, we are currently pathotyping these wheat cultivars with a French Pn isolate producingTox1 and 3. Mapping of loci controlling insensitivity to Pn necrotrophic effectors and resistance to Pnisolate will be performed using genome-wide association analyses. This project will facilitate plantbreeding efforts to select for resistance to important fungal pathogens by providing a ‘toolkit’ of bio-molecular markers