A Blast-Resistant NLR Gene Confers Drought Resistance by Competitively Interacting with an E3 Ligase to Protect Phenylalanine Ammonia-Lyase in Rice

Abstract

Drought and diseases represent major challenges to achieve high yield in crops, underscoring the urgent need to explore drought- and disease-resistant genetic resources and breed crop varieties with multi-stress resistance. Here, using a genome-wide association study combined with function analyses, PibH8, a homologous of the blast resistance gene Pib encoding a nucleotide-binding leucine-rich repeat receptor (NLR) is identified, which plays a crucial role in rice drought resistance. PibH8 interacts with phenylalanine ammonia-lyase OsPAL1, a rate-limiting enzyme in phenylpropanoids biosynthesis pathway in rice. It protects OsPAL1 from degradation by competitively binding to E3 ubiquitin ligase OsFBK16, which facilitates OsPAL1 degradation. This protective mechanism enhances PAL activity, leading to increased lignin and flavonoids content and improved drought resistance. Genetic evidence indicates that PibH8 acts upstream of OsPAL1 in conferring drought resistance. Furthermore, a causal variation in the PibH8 promoter that is associated with drought resistance is identified. Introgression of a superior haplotype, which exhibits high PibH8 expression, into the elite rice variety Kongyu131 significantly improved drought and blast resistance. This research not only elucidates a regulatory mechanism of NLR protein in drought resistance, but also highlights a promising breeding value of PibH8 for simultaneously improving drought and blast resistance.