Mutation of a Nucleotide-Binding Leucine-Rich Repeat Immune Receptor-Type Protein Disrupts Immunity to Bacterial Blight

• Published in: Plant physiology (Bethesda) 2019-11, Vol.181 (3), p.1295-1313
• Main Authors: Tang, Jiuyou, Wang, Yiqin, Yin, Wenchao, Dong, Guojun, Sun, Kai, Teng, Zhenfeng, Wu, Xujiang, Wang, Shimei, Qian, Yangwen, Pan, Xuebiao, Qian, Qian, Chu, Chengcai
• Format: Article
• Language: English
• Subjects: Gene Expression Regulation, Plant - genetics; Leucine-Rich Repeat Proteins; Mutation - genetics; Oryza - genetics; Oryza - metabolism; Oryza - microbiology; Plant Diseases - microbiology; Plant Proteins - genetics; Plant Proteins - metabolism; Proteins - genetics; Proteins - metabolism; Xanthomonas - pathogenicity
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.19.00686

Most characterized plant resistance proteins belong to the nucleotide-binding domain and Leu-rich repeat-containing (NLR) family. NLRs are present in an auto-inhibited state in the absence of specific pathogens, while gain-of-function mutations in NLRs usually cause autoimmunity. Here, we show that a gain-of-function mutation, ( ), which caused a Phe-to-Leu substitution in the nucleotide-binding domain of a typical NLR in rice ( ), led to enhanced susceptibility to pv. The unexpected accumulation of salicylic acid (SA), along with downregulation of ( ), in indicates the potential presence of a feedback regulation loop of SA biosynthesis in rice. Epistasis analyses illustrated that SA accumulation and the NLR-associated components RAR1, OsRac1, and PhyB are dispensable for the phenotypes. Intriguingly, besides pattern-triggered immunity, effector-triggered immunity conferred by different resistance proteins, including Xa3/Xa26, Xa4, and Xa21, was also disturbed by to a certain extent, indicating the existence of shared regulatory mechanisms for various defense systems. The identification of therefore provides a unique system for genetic dissection of shared immune signaling pathways activated by different types of immune receptors.