香蕉细菌性软腐病菌tus基因对细菌生物被膜形成的影响  

Functional analysis of tus genes that affect the biofilm formation of banana soft rot pathogen Dickeya zeae

作　　者：蒋尚伯 孙大元[1] 唐子晴 沈会芳[1] 蒲小明[1] 林壁润[1] 杨祁云[1] 张景欣[1] Jiang Shangbo;Sun Dayuan;Tang Ziqing;Shen Huifang;Pu Xiaoming;Lin Birun;Yang Qiyun;Zhang Jingxin(Guangdong Provincial Key Laboratory of High Technology for Plant Protection,Plant Protection Research Institute,Guangdong Academy of Agricultural Sciences,Guangzhou 510640,Guangdong Province,China)

机构地区：[1]广东省农业科学院植物保护研究所,广东省植物保护新技术重点实验室,广州510640

出　　处：《植物保护学报》2023年第5期1161-1175,共15页Journal of Plant Protection

基　　金：广东省基础与应用基础研究基金项目(2022A1515010082);广东省现代农业产业绿色发展共性关键技术研发创新团队建设项目(2023KJ112);广东省农业科学院协同创新中心项目(XTXM202202);广东省农业科学院科技创新战略专项资金(R2017YJ-YB2002)。

摘　　要：为解析硫转运蛋白(tRNA 2-thiouridine synthesizing protein,tus)基因对香蕉细菌性软腐病病原细菌——玉米迪基氏菌Dickeya zeae生物被膜形成的影响,采用同源重组方法构建6株tus基因的缺失突变体及回补菌株,分析代表性突变体的转录组差异,并测定不同突变体的运动能力、细胞壁降解酶分泌水平以及对烟草的致敏性和对寄主的毒力,解析突变体生物被膜表型发生变异的原因。结果显示,玉米迪基氏菌的6株tus基因缺失突变体ΔtusA、ΔtusB、ΔtusC、ΔtusD、ΔtusE和ΔmnmA均表现出生物被膜表型缺陷;ΔtusC突变体转录组比较分析表明,细菌生物被膜形成和运动性相关基因均属于细胞进程中的显著下调表达基因,且前者主要为Ⅵ型分泌系统(type VI secretion system,T6SS)基因,进一步分析发现3个位点的T6SS基因均出现显著下调表达趋势;6株tus基因缺失突变体的运动能力显著减弱,但是细胞壁降解酶分泌水平和对烟草的致敏性并未发生显著变化;接种野生型菌株和基因回补菌株后香蕉的病情指数为42.5~67.5,而接种突变体后香蕉的病情指数下降至5.0~17.5,突变体的毒力下降。表明tus基因在玉米迪基氏菌生物被膜形成过程中具有重要功能。To reveal the effects of tRNA 2-thiouridine-synthesizing protein genes,tus,on biofilm formation of banana soft rot pathogen Dickeya zeae,the gene deletion mutants and their complementary strains were constructed for all of six tus genes by homologous recombination,and were used for exploring the mechanism of their biofilm phenotypic change.In combination with comparative transcriptome analysis of representative gene deletion mutant,six deletion mutants were further tested for bacterial motility,secretion of cell wall degradation enzymes,hypersensitive reaction in tobacco,and virulence on banana host.Six gene deletion mutants,ΔtusA,ΔtusB,ΔtusC,ΔtusD,ΔtusE andΔmnmA,all showed obvious phenotypic defects on bacterial biofilm.Comparative transcriptome analysis betweenΔtusC mutant and wild-type revealed that those genes related to bacterial biofilm formation and motility mainly consisted of the significantly down-regulated gene group within cellular process,while bacterial biofilm formation genes were mainly the type VI secretory system(T6SS)genes.Further analysis found that T6SS genes at three different genome loci were significantly down regulated.For the bacterial motility,these six gene mutants were significantly weakened at their bacterial motility,but there were no obvious changes in cell wall-degrading enzymes secretion and tobacco hypersensitivity.The disease indexes of banana seedlings inoculated with wild-type and gene complementary strains were 42.5-67.5,while those inoculated with six tus gene mutants decreased to 5.0-17.5.Thus,the tus genes play important roles in the formation of bacterial biofilm of this D.zeae pathogen.

关 键 词：香蕉细菌性软腐病菌 tus基因 转录组测序 生物被膜 运动性 

分 类 号：S436.68[农业科学—农业昆虫与害虫防治]