Genetic Decryption of Stripe Rust Resistant Gene (Yr24) In Bread Wheat

Abstract

Wheat is the most significant cereal crop across the world, which means that it has to deal with a wide range of diseases as well. Wheat breeders have worked over the years to collect genetic and genomic resources to reduce the losses to wheat diseases. To demonstrate this translational approach, we used reverse genetic method to clone and validate stripe rust loci in bread wheat. Integration of recently available wheat genome sequence, its annotation and genetic mapping of resistance loci in bread wheat now enables us to use transitional reverse genetics in bread wheat. 147 genetic loci were positioned on WCGM2019. Markers of WCGM2019 were aligned to Wheat genome sequence to identify the regions and putative candidate genes in bread wheat. To validate this reverse genetic approach, we used near isogenic lines of stripe rust from CIMMYT Mexico. 23 Nils for stripe rust along with susceptible check (cultivar Morocco) were screened under controlled conditions in glass house at Crop Disease Research Institute (CDRI) Murree with races 574232, 574207, 574210 and 574203 to find genes avirulent to these races. Yr24 (uncloned), Yr10 (cloned) and Yr15 (cloned) gave avirulent results against the inoculated pathotypes. QRT-PCR was used to identify the candidate genes for Yr24 and to verify the genes resistant to Yr10 and Yr15. Overall, this study illustrates a translational research approach in transferring information gained from wheat genome sequence to dissect the genomic regions for disease resistance, development of diagnostic chip base markers and associated candidate genes to be now considered as a key resource for breeding programs