近日，美国加州大学伯克利分校的Sheng Luan研究组发现了一个钙调蛋白门控的钙离子通道参与植物免疫调控。2019年8月1日出版的《自然》发表了这项成果。

研究人员发现，钙离子营养状态对植物中钙离子依赖的PAMP激活免疫十分关键。当钙供应充足时，两个编码环核苷酸门控通道（CNGC）蛋白的基因，CNGC2和CNGC4，对拟南芥中PAMP引起的钙信号传导是必需的。在体外重组系统中，研究人员发现CNGC2和CNGC4只有同时存在时能够组装成有功能的钙离子通道，这个通道在静息态时被钙调蛋白所封闭。受到病原体攻击时，这个通道能够被模式识别复合物中的效应蛋白激酶BIK1磷酸化并激活，从而触发胞浆中钙离子浓度的增加。因此，在植物中由PAMP激活的免疫信号通路里，CNGC介导的钙离子内流为模式识别受体复合物与钙离子依赖的免疫提供了一个关键的联系。

据了解，病原体相关分子模式（PAMP）参与激活动物和植物的先天免疫。虽然钙离子一直被认为是植物中PAMP激活免疫的一个关键信号，但PAMP引起钙信号的机理仍然未知。


Title: A calmodulin-gated calcium channel links pathogen patterns to plant immunity

Author: Wang Tian, Congcong Hou, Zhijie Ren, Chao Wang, Fugeng Zhao, Douglas Dahlbeck, Songping Hu, Liying Zhang, Qi Niu, Legong Li, Brian J. Staskawicz, Sheng Luan

Issue&Volume: Volume 572 Issue 7767

Abstract: Pathogen-associated molecular patterns (PAMPs) activate innate immunity in both animals and plants. Although calcium has long been recognized as an essential signal for PAMP-triggered immunity in plants, the mechanism of PAMP-induced calcium signalling remains unknown. Here we report that calcium nutrient status is critical for calcium-dependent PAMP-triggered immunity in plants. When calcium supply is sufficient, two genes that encode cyclic nucleotide-gated channel (CNGC) proteins, CNGC2 and CNGC4, are essential for PAMP-induced calcium signalling in Arabidopsis. In a reconstitution system, we find that the CNGC2 and CNGC4 proteins togetherbut neither aloneassemble into a functional calcium channel that is blocked by calmodulin in the resting state. Upon pathogen attack, the channel is phosphorylated and activated by the effector kinase BOTRYTIS-INDUCED KINASE1 (BIK1) of the pattern-recognition receptor complex, and this triggers an increase in the concentration of cytosolic calcium. The CNGC-mediated calcium entry thus provides a critical link between the pattern-recognition receptor complex and calcium-dependent immunity programs in the PAMP-triggered immunity signalling pathway in plants.

DOI: 10.1038/s41586-019-1413-y

Source: https://www.nature.com/articles/s41586-019-1413-y