From defense to symbiosis; evolution processes of plant symbiotic receptor

植物病原菌的侵染策略正在迅速进化，并发展出许多干扰宿主免疫系统的毒力因子。因此，植物在自然界中不断受到病原微生物的威胁。相反，丛枝菌根（AM）真菌或根瘤菌等微生物亚群可以共生促进寄主植物的生长。植物如何在接受有益微生物的同时排斥病原体是理解植物与微生物相互作用的关键问题。然而，这个问题很少被触及，答案仍然缺失。在这里，我们报道了一种几丁质受体激酶，OsCERK1，在水稻中参与触发植物免疫反应和接受有益的AM真菌。这些发现首次阐明了植物防御与共生机制之间存在直接联系，有望成为该领域的突破。

Plant pathogens have been rapidly evolving their strategy for infection and developing many virulence agents for perturbing host immune system. Thus, plants are constantly exposed to threats from pathogenic microbes in nature. On the contrary, subsets of microbes such as arbuscular mycorrhizal (AM) fungi or rhizobial bacteria symbiotically promote the host plant growth. How plants manage the acceptance of beneficial microbes while rejecting pathogens is a crucial question for understanding the plant-microbe interactions. However, this question has been rarely approached and the answer is still missing. Here, we report that a chitin receptor kinase, OsCERK1, engages in both triggering plant immune responses and acceptance of beneficial AM fungi in rice. These findings illuminate the presence of direct connection between plant defense and symbiotic mechanisms for the first time and are expected to be a breakthrough for this field.