西瓜噬酸菌Ⅲ型分泌系统hrcS基因功能分析  

Functional analysis of hrcS gene in typeⅢsecretion system of bacterial pathogen Acidovorax citrulli

作　　者：白庆荣 范泽慧 关巍 杨琳琳 杨玉文[2] 赵廷昌[2] Bai Qingrong;Fan Zehui;Guan Wei;Yang Linlin;Yang Yuwen;Zhao Tingchang(College of Plant Protection,Jilin Agricultural University,Changchun 130118,Jilin Province,China;State Key Laboratory for Biology of Plant Diseases and Insect Pests,Institute of Plant Protection,Chinese Academy of Agricultural Sciences,Beijing 100193,China)

机构地区：[1]吉林农业大学植物保护学院,长春130118 [2]中国农业科学院植物保护研究所,植物病虫害生物学国家重点实验室,北京100193

出　　处：《植物保护学报》2023年第2期350-358,共9页Journal of Plant Protection

基　　金：国家重点研发计划(2018YFD0201300,2017YFD0201608);财政部和农业农村部国家西甜瓜产业技术体系(CARS-25);中央级公益性科研院所基本科研业务费专项(S2019XM06);中国农业科学院创新工程。

摘　　要：为明确编码Ⅲ型分泌系统(typeⅢsecretion system,T3SS)中重要核心蛋白的hrcS基因对西瓜噬酸菌Acidovorax citrulli致病力的影响,以西瓜噬酸菌野生型菌株Aac5为对象,通过基因敲除构建hrcS基因缺失突变菌株ΔhrcS及其互补菌株ΔhrcS-comp,测定其致病力及致病相关基因表达量、烟草过敏性反应能力、运动能力及运动能力相关基因表达量、生物膜形成能力和离体生长能力。结果显示,与野生型菌株Aac5相比,hrcS基因缺失突变菌株丧失了对寄主的致病能力和引起非寄主烟草过敏性反应能力,运动能力显著增强了191.75%,生物膜形成能力显著下降了43.90%,离体生长能力在达到对数期后呈下降趋势。hrcS基因缺失使西瓜噬酸菌T3SS中hrpG、hrpX和hrpE基因以及鞭毛fliC基因表达量显著上调,分别为野生型菌株的2.27倍、2.38倍、1.26倍和1.77倍,hrcQ基因表达量显著下调,仅为野生型菌株的50.75%。表明hrcS基因在维持西瓜噬酸菌致病能力中发挥着重要作用。In order to understand the role of hrcS gene encoding core protein of type III secretion system(T3SS)in the pathogenicity of Acidovorax citrulli,the hrcS deletion strainΔhrcS,and its complementation strainΔhrcS-comp were derived from Aac5,a wild type strain of A.citrulli in this study.The pathogenicity and the expression levels of genes involved in pathogenicity,hypersensitive response on tobacco,motility and the expression levels of genes involved in motility,biofilm formation,in vitro growth rate of the A.citrulli strains were determined.The results showed that the hrcS deletion mutant strain lost its virulence to the watermelon seedlings and the ability to induce hypersensitive reaction on non-host Nicotiana tabacum.Compared to the wild type strain Aac5,the swimming motility of the mutant strain significantly increased by 191.75%,while the biofilm formation decreased by 43.90%,and the in vitro growth rate decreased after logarithmic phase.The hrcS gene deletion significantly increased the expression level of T3SS genes hrpG,hrpX,hrpE and flagellin gene fliC by 2.27,2.38,1.26 and 1.77 times,respectively.However,the expression level of T3SS gene hrcQ was significantly reduced by 50.75%.These results indicated that the gene hrcS plays an important role in maintaining the pathogenicity of A.citrulli.

关 键 词：西瓜噬酸菌 Ⅲ型分泌系统 hrcS基因 基因功能 致病力 

分 类 号：S436.5[农业科学—农业昆虫与害虫防治]