植物TIR-NB-LRR类型抗病基因各结构域的研究进展

植物抗病反应是一个多基因调控的复杂过程,在这个过程中R基因发挥了非常重要的作用。根据其氨基酸基序组成以及跨膜结构域的不同,R基因可以分为多种类型,其中NBS-LRR类型是植物基因组中最大的基因家族之一。TIR-NB-LRR类型的抗病基因又是NB-LRR类型中的一大类,也是目前抗病基因研究的热点。该文总结了TIR-NB-LRR类型抗病基因各个结构域的功能和相关的研究进展。相关研究表明,TIR结构域主要通过自身或异源的二聚体化介导抗性信号的转导,但也有部分研究表明,该结构域可能参与病原菌的特异性识别。NBS结构域常被认为具有"分子开关"的功能,它可以通过结合ADP或ATP来调节植物抗病蛋白的构象变化,从而调节下游抗病信号的传导。LRR结构域在植物与病原菌互作的过程中可以通过与病原菌的无毒蛋白直接或间接互作来特异识别病原菌。也有研究发现,LRR结构域具有调节信号传导的功能。这些信息将为研究植物抗病机理提供理论依据,也为将来通过基因编辑技术对作物进行定向抗病育种提供思路。

Research progress on domains of plant TIR-NB-LRR resistance genes

Plant disease-resistance response is a complex process which is regulated by multiple genes. Plant resistance genes(R genes)play an important role in this process. R genes can be divided into different types based on their N-terminal and transmembrane domains. The majority of disease resistance genes in plants encode nucleotide-binding site leucine-rich repeat(NBS-LRR)proteins. The TIR-NB-LRR(TNL)type is a large family of plant NB-LRR genes. And it is also the current hot topics in the studies of plant disease resistance genes. We summarized the related research progresses of different domains of TNL proteins comprehensively in this review. TIR domain in resistance signaling via homodimerization or heterodimerization is a major role of plant TNL proteins. However, emerging roles for pathogen recognition for the plant TIR domain were identified in some researches. The NBS domain in NBS-LRR proteins was proposed to function as a molecular switch. It can adjust the conformation changes of plant R proteins through binding ADP or ATP, which regulates resistance signal conduction downstream. The LRRs of plant TIR-NB-LRR proteins were predicted to interact directly or indirectly with their avirulent effectors to recognize the pathogen specifically. The information provides a good theory basis for study of plant disease-resistance mechanisms, and also provides new insights and choices for crop disease-resistance breeding directionally by gene editing technology in the future.