The survival of all living organisms requires the ability to detect attacks and swiftly counter them with protective immune responses. Despite considerable mechanistic advances, the interconnectivity of signalling modules often remains unclear. A newly characterized protein, IMMUNOREGULATORY RNA-BINDING PROTEIN (IRR), negatively regulates immune responses in both maize and Arabidopsis, with disrupted function resulting in enhanced disease resistance. IRR associates with and promotes canonical splicing of transcripts encoding defence signalling proteins, including the key negative regulator of pattern-recognition receptor signalling complexes, CALCIUM-DEPENDENT PROTEIN KINASE 28 (CPK28). On immune activation by Plant Elicitor Peptides (Peps), IRR is dephosphorylated, disrupting interaction with CPK28 transcripts and resulting in the accumulation of an alternative splice variant encoding a truncated CPK28 protein with impaired kinase activity and diminished function as a negative regulator. We demonstrate a new mechanism linking Pep-induced post-translational modification of IRR with post-transcriptionally mediated attenuation of CPK28 function to dynamically amplify Pep signalling and immune output.

所有生物体的生存都需要能够检测攻击并通过保护性免疫反应迅速反击它们。尽管在机械方面取得了相当大的进步，但信号模块的互连性通常仍不清楚。一种新表征的蛋白质，即免疫调节 RNA 结合蛋白 (IRR)，在玉米和拟南芥中负向调节免疫反应，破坏功能导致抗病性增强。IRR 与编码防御信号蛋白的转录本相关并促进规范剪接，包括模式识别受体信号复合物的关键负调节因子钙依赖性蛋白激酶 28 (CPK28)。在植物诱导肽 (Peps) 的免疫激活过程中，IRR 被去磷酸化，破坏与CPK28转录并导致编码截短的 CPK28 蛋白的替代剪接变体的积累，具有受损的激酶活性和减弱的负调节功能。我们展示了一种新机制，将 Pep 诱导的 IRR 翻译后修饰与转录后介导的 CPK28 功能衰减联系起来，以动态放大 Pep 信号传导和免疫输出。