植物先天性免疫反应中的细胞死亡及其调控

先天性免疫反应是植物应对外来病原微生物侵害的一种主要策略。与动物相比，植物没有特异性的免疫细胞，其被侵染的细胞需通过复杂的监控机制来启动和激活先天性免疫反应，细胞死亡在该反应中发挥着重要作用。动物中的凋亡、自噬和坏死3种细胞死亡类型在植物细胞中均可能存在，且参与调控植物的免疫反应。植物既可利用产生的活性氧（reactive oxygen species，ROS）等物质抑制或杀死病原菌，也可通过程序性细胞死亡（programmed cell death，PCD）限制病原菌的侵染和扩展。目前，有关植物细胞死亡的作用和调控机制的研究报道还比较紊乱。本文从以下几方面对近年来关于细胞死亡在植物先天性免疫反应中的功能及其调控机制的研究进展进行了概述：1）植物细胞死亡的种类；2）细胞死亡参与不同层面植物免疫反应的功能；3）ROS、植物激素和蛋白酶等因子参与调控PCD的功能和机制。同时，对不同细胞死亡信号途径的交叉互作在植物免疫反应中的功能和作用机制提出假说，以期为植物抗病育种提供理论依据。
Plants have deployed a highly sophisticated innate immune system that enables them to perceive potentially dangerous microbes. Unlike the animals which have developed specialized immune cells, the activation of plant immunity relies on the detection of pathogens by the infected cells themselves, among which the cell death plays a central role in plant innate immune response. Three morphologically distinct forms of cell death including apoptosis, autophagy and necrosis, which have been described in animals systems, may play important roles in plant immune response to pathogens. During the immune response, on the one hand, the production of reactive oxygen species (ROS)show direct antimicrobial functions;on the other hand, ROS can also limit the spreading of pathogens via programmed cell death (PCD). However, the functions and mechanisms underlying the regulation of cell death in plants are still not fully understood. In this review, we summarized the recent important advances:1)different forms of plant cell death, 2)the functions of cell death in plant immune response, 3)the roles of ROS, phytohormones and proteases in the regulation of plant PCD. Moreover, we proposed the possible crosstalk between distinct signaling pathways involved in the regulation of plant cell death during immune response, which will provide a theoretical basis for the breeding of plants with enhanced disease resistance