Nucleotide-binding site–leucine-rich repeat (NB-LRR) resistance proteins are critical for plant resistance to pathogens; however, their mechanism of activation and signal transduction is still not well understood. We identified a mutation in an as yet uncharacterized rice coiled-coil (CC)-NB-LRR, Oryza sativa RPM1-like resistance gene 1 (OsRLR1), which leads to hypersensitive response (HR)-like lesions on the leaf blade and broad-range resistance to the fungal pathogen Pyricularia oryzae (syn. Magnaporthe oryzae) and the bacterial pathogen Xanthomonas oryzae pv. oryzae, together with strong growth reduction. Consistently, OsRLR1-overexpression lines showed enhanced resistance to both pathogens. Moreover, we found that OsRLR1 mediates the defence response through direct interaction in the nucleus with the transcription factor OsWRKY19. Down-regulation of OsWRKY19 in the rlr1 mutant compromised the HR-like phenotype and resistance response, and largely restored plant growth. OsWRKY19 binds to the promoter of OsPR10 to activate the defence response. Taken together, our data highlight the role of a new residue involved in the NB-LRR activation mechanism, allowing identification of a new NB-LRR downstream signalling pathway.

中文翻译：

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CC-NB-LRR OsRLR1通过与OsWRKY19的相互作用介导水稻抗病性

核苷酸结合位点-富含亮氨酸的重复（NB-LRR）抗性蛋白对于植物对病原体的抗性至关重要。然而，它们的激活和信号转导的机制仍未得到很好的理解。我们在尚未鉴定的水稻卷曲螺旋（CC）-NB-LRR，稻米RPM1样抗性基因1（OsRLR1）中鉴定出一个突变，该突变导致叶片和宽阔叶片上的超敏反应（HR）样损伤真菌病原体Pyricularia oryzae（Syn。Magnaporthe oryzae）和细菌病原体Xanthomonas oryzae pv的近距离抗性。稻米，以及强劲的增长减缓。一致地，OsRLR1-过表达系显示出对两种病原体的增强的抗性。此外，我们发现OsRLR1通过与转录因子OsWRKY19在细胞核中的直接相互作用介导防御反应。rlr1突变体中OsWRKY19的下调损害了HR样表型和抗性反应，并在很大程度上恢复了植物的生长。OsWRKY19结合到启动子OsPR10激活防御反应。综上所述，我们的数据强调了新残基在NB-LRR激活机制中的作用，从而鉴定了新的NB-LRR下游信号通路。