Abstract

Reducing loss caused by pathogens represents a credible strategy for stabilizing crop yields. Daunting challenges remain in cloning and deciphering genes inhibiting stripe rust, a devastating disease caused by Puccinia striiformis f. sp. tritici (Pst) of wheat (Triticum aestivum). We revealed that suppressing wheat zeaxanthin epoxidase 1 (ZEP1) increased wheat defense against Pst. We isolated the yellow rust slower 1 (yrs1) mutant in which a premature stop mutation in tetraploid wheat ZEP1-B underpins the phenotype. Genetic analyses revealed increased H 2 O 2 accumulation in zep1 mutants and demonstrated the correlation between ZEP1 dysfunction and slower Pst growth in wheat. Moreover, Wheat Kinase START 1.1 (WKS1.1, Yr36) bound, phosphorylated, and suppressed the biochemical activity of ZEP1. A rare natural allele in the hexaploid wheat ZEP1-B promoter reduced its transcription activity and Pst growth. Our study identified a novel suppressor of Pst, illustrated its working mechanism, and revealed the beneficial variation to control wheat disease. This work opened the door to stacking the wheat ZEP1 variations with other known Pst resistance genes in future breeding programs to enhance wheat tolerance to pathogens.