Plant pathogens secrete cell wall-degrading enzymes that degrade various components of the plant cell wall. Plants sense this cell wall damage as a mark of infection and induce immune responses. However, the plant functions that are involved in the elaboration of cell wall damage-induced immune responses remain poorly understood. Transcriptome analysis revealed that a rice (Oryza sativa) receptor-like kinase, WALL-ASSOCIATED KINASE-LIKE21 (OsWAKL21.2), is up-regulated following treatment with either Xanthomonas oryzae pv oryzae (a bacterial pathogen) or lipaseA/esterase (LipA; a cell wall-degrading enzyme of X. oryzae pv oryzae). Overexpression of OsWAKL21.2 in rice induces immune responses similar to those activated by LipA treatment. Down-regulation of OsWAKL21.2 attenuates LipA-mediated immune responses. Heterologous expression of OsWAKL21.2 in Arabidopsis (Arabidopsis thaliana) also activates plant immune responses. OsWAKL21.2 is a dual-activity kinase that has in vitro kinase and guanylate cyclase activities. Interestingly, kinase activity of OsWAKL21.2 is necessary to activate rice immune responses, whereas in Arabidopsis, OsWAKL21.2 guanylate cyclase activity activates these responses. Our study reveals a rice receptor kinase that activates immune responses in two different species via two different mechanisms.

植物病原体分泌可降解植物细胞壁各种成分的细胞壁降解酶。植物将这种细胞壁损坏视为感染的标志并诱导免疫反应。然而，涉及细胞壁损伤诱导的免疫反应的详细的植物功能仍然知之甚少。转录组分析揭示，稻（稻）受体样激酶，WALL-相关激酶LIKE21（OsWAKL21.2），上调与任一下列治疗黄单胞菌PV菌（细菌病原体）或脂肪酶A /酯酶（LipA的；X。oryzae pv oryzae的细胞壁降解酶）。过度表达水稻中的OsWAKL21.2诱导的免疫反应与LipA处理激活的反应相似。下调OsWAKL21.2衰减的LipA介导的免疫反应。OsWAKL21.2在拟南芥（Arabidopsis thaliana）中的异源表达也激活了植物的免疫反应。OsWAKL21.2是一种双重活性激酶，具有体外激酶和鸟苷酸环化酶活性。有趣的是，OsWAKL21.2的激酶活性是激活水稻免疫应答所必需的，而在拟南芥中，OsWAKL21.2的鸟苷酸环化酶活性可以激活这些应答。我们的研究揭示了一种水稻受体激酶，可通过两种不同的机制激活两种不同物种的免疫反应。