CsMLO8/11 are required for full susceptibility of cucumber stem to powdery mildew and interact with CsCRK2 and CsRbohD

作者：Shaoyun Dong, Xin Liu, Jianan Han, H. Miao, Diane M. Beckles, Yuling Bai, Xiaoping Liu, Jiantao Guan, Ruizhen Yang, Xingfang Gu, Jiaqiang Sun, Xue Yang, Shengping Zhang · 发表于：Horticulture Research · 年份：2023 · DOI：10.1093/hr/uhad295 · 被引用次数：27 · 研究领域：Plant-Microbe Interactions and Immunity、Advances in Cucurbitaceae Research、Plant Disease Resistance and Genetics

Abstract Powdery mildew (PM) is one of the most destructive diseases that threaten cucumber production globally. Efficient breeding of novel PM-resistant cultivars will require a robust understanding of the molecular mechanisms of cucumber resistance against PM. Using a genome-wide association study, we detected a locus significantly correlated with PM resistance in cucumber stem, pm-s5.1. A 1449-bp insertion in the CsMLO8 coding region at the pm-s5.1 locus resulted in enhanced stem PM resistance. Knockout mutants of CsMLO8 and CsMLO11 generated by CRISPR/Cas9 both showed improved PM resistance in the stem, hypocotyl, and leaves, and the double mutant mlo8mlo11 displayed even stronger resistance. We found that reactive oxygen species (ROS) accumulation was higher in the stem of these mutants. Protein interaction assays suggested that CsMLO8 and CsMLO11 could physically interact with CsRbohD and CsCRK2, respectively. Further, we showed that CsMLO8 and CsCRK2 competitively interact with the C-terminus of CsRbohD to affect CsCRK2-CsRbohD module-mediated ROS production during PM defense. These findings provide new insights into the understanding of CsMLO proteins during PM defense responses.