The genetic architecture of resistance to septoria tritici blotch in French wheat cultivars

Septoria tritici blotch, caused by the fungus Zymoseptoria tritici, is a foliar disease particularly harmful to wheat cultivation. Since the early 2000s, numerous studies on the genetics of resistance to this disease have been conducted on bread wheat. These studies have notably led to the identification of 23 resistance genes, known as Stb genes, as well as numerous resistance QTLs. However, few of these studies specifically focus on elite French varieties, and our understanding of their genetic content in terms of resistance has so far been very limited. INRAE's GDEC and BIOGER units collaborated closely with French wheat breeders and the technical institute ARVALIS (via the BreedWheat consortium) to characterize a collection of 285 elite French bread wheat varieties. The resistance or susceptibility level of each variety was evaluated using two Z. tritici strains under field conditions and 10 strains under controlled conditions. A genome-wide association study (GWAS) then identified 57 resistance QTLs, 40 of which were found to be effective under controlled conditions. These results suggest that at least 11 of the 23 known Stb genes are present in French varieties, and they also led to the identification of new Stb genes. Understanding these genes is crucial for breeding increasingly resistant wheat varieties. This work also provides a vital foundation for a comprehensive meta-analysis of resistance genetics currently underway as part of the FSOV DURABLÉ project (2019–2023).

More information on the ANR Breedwheat project: https://www.franceagrimer.fr/content/download/50194/document/Breedwheat_brochure%20FR-4pages%281%29.pdf

More information on the FSOV DivR project: https://www.fsov.org/des-outils-moleculaires-pour-la-selection-de-resistances-diversifiees-et-efficaces-contre-la-septoriose-du-ble

Reference: Thauvin, JN., Gélisse, S., Cambon, F. et al. The genetic architecture of resistance to septoria tritici blotch in French wheat cultivars. BMC Plant Biol 24, 1212 (2024) https://doi.org/10.1186/s12870-024-05898-5