番茄细菌性斑点病菌无毒基因研究进展

番茄细菌性斑点病是影响番茄产量和品质的重要病害,Pseudomonas syringaepv.tomato(Pst)为其病原菌,其与番茄的互作系统是研究植物抗感病机理的典型模式系统。Pst存在2种无毒基因:avrPto和avrPtoB,它们编码的蛋白质均能与番茄抗性基因Pto编码的Ser-Thr蛋白激酶互作,符合Flor"基因对基因"学说。AvrPto和AvrPtoB在表达Pto的抗性植物中,与Pto互作,表现无毒功能,引发植物防御反应;而在缺失Pto的感病植物中,它们具有毒性,促进细菌的生长。本文综述了番茄细菌性斑点病菌无毒基因avrPto及avrPtoB的结构特点及其功能,这有助于了解病原物与植物的互作机制,对认识植物的感病性、抗病性以及植物防御反应都具有重要意义。

Advances in the avirulence genes in Pseudomonas syringae pv. tomato

The tomato bacterial speak disease is the main disease that can affect the quantity and quality of tomatoes.Pseudomonas syringae pv.tomato(Pst) is the pathogen of bacterial speck disease in the tomato and Arabidopsis.The interaction between P.s.pv.tomato and tomato has been established as a typical model system for studying plant-pathogen interaction.There are two types of avirulence genes in P.s.pv.tomato,avrPto and avrPtoB.Their encoded proteins can separately and specifically interact with the resistance protein Pto of tomato,a Ser-Thr kinase protein.It matches with Flor's hypothesis of "gene for gene" reaction.Pst elicits immunity-associated programmed cell death(PCD) when inoculated on tomato plants carrying Pto.However,in tomato plants lacking Pto,they function to suppress immunity in plants and promote bacterial growth.This paper reviews the tomato bacterial speck disease and the avirulence genes,avrPto and avrPtoB,and their construction characteristics and functions.It is helpful to understand the mechanisms of plant-pathogen interaction,since it will contribute to understanding plant susceptibility,resistance as well as plant defense responses.