Transcriptomic analysis of wheat reveals possible resistance mechanism mediated by Yr10 to stripe rust.

Abstract

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a catastrophic disease that threatens global wheat yield. Yr10 is a race-specific all-stage disease resistance gene in wheat. However, the resistance mechanism of Yr10 is poorly characterized. Therefore, to elucidate the potential molecular mechanism mediated by Yr10, transcriptomic sequencing was performed at 0, 18, and 48 h post-inoculation (hpi) of compatible wheat Avocet S (AvS) and incompatible near-isogenic line (NIL) AvS + Yr10 inoculated with Pst race CYR32. Respectively, 227, 208, and 4050 differentially expressed genes (DEGs) were identified at 0, 18, and 48 hpi between incompatible and compatible interaction. The response of Yr10 to stripe rust involved various processes and activities, as indicated by the results of Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Specifically, the response included photosynthesis, defense response to fungus, metabolic processes related to salicylic acid (SA) and jasmonic acid (JA), and activities related to reactive oxygen species (ROS). Ten candidate genes were selected for qRT-PCR verification and the results showed that the transcriptomic data was reliable. Through the functional analysis of candidate genes by the virus-induced gene silencing (VIGS) system, it was found that the gene TaHPPD (4-hydroxyphenylpyruvate dioxygenase) negatively regulated the resistance of wheat to stripe rust by affecting SA signaling, pathogenesis-related (PR) gene expression, and ROS clearance. Our study provides insight into Yr10-mediated resistance in wheat.