西瓜嗜酸菌双精氨酸转运系统基因(tatB)功能分析  

Functional Analysis of Twin-arginine Translocation System Gene(tatB)in Acidovorax citrulli

作　　者：蒋洁[1] 孙柏欣[1,2] 安心[1,2] 王铁霖[1] 李强[1] 董春玲[1] 杨玉文[1] 赵廷昌[1] 

机构地区：[1]中国农业科学院植物保护研究所,北京100193 [2]沈阳农业大学,沈阳110161

出　　处：《农业生物技术学报》2014年第6期753-761,共9页Journal of Agricultural Biotechnology

基　　金：公益性行业(农业)科研专项(No.201003066);国家西甜瓜产业技术体系(No.CARS-26);中国农业科学院科技创新工程(No.nkyzb003)

摘　　要：细菌双精氨酸转运系统(twin-arginine translocation system,Tat)可严重影响动植物病原细菌的致病性,为了研究Tat与西瓜嗜酸菌(Acidovorax citrulli)致病性的关系,本研究通过同源重组的方法构建了西瓜嗜酸菌的tatB基因缺失菌株(ΔtatB)以及互补菌株(CtatB),并从西瓜嗜酸菌致病能力、游动能力、生长能力、胞外多糖与胞外纤维素酶产生能力以及生物膜形成等方面阐明Tat系统对西瓜嗜酸菌的影响。实时荧光定量PCR探究tatB基因与Ⅲ型分泌系统相关基因(hrcN)和(hrpE)、Tat转运系统相关基因(Aave_1810)和(Aave_0034)以及细胞毒性相关基因(TrbC)的关系。结果表明,ΔtatB能够引起非寄主植物烟草(Nicotiana tabacum)的过敏性反应;tatB基因的缺失导致了嗜酸菌的致病力、游动能力和对数生长初期的生长能力下降;不影响西瓜嗜酸菌胞外多糖、胞外纤维素酶的产生以及生物膜的形成;导致了TrbC和hrcN基因表达量显著升高,Aave_1810、Aave_0034和hrpE基因的表达量显著降低。研究结果表明,Tat系统相关基因tatB的缺失会影响西瓜嗜酸菌一些生物学特性,并导致病菌致病能力降低。本研究为西瓜嗜酸菌Ⅲ型分泌系统外的其他分泌系统与致病性的关系研究提供了基础资料。Bacteria＇s twin-arginine translocation system（Tat） can affect its pathogenicity seriously. In order to explore the relationship between Tat and pathogenicity of Acidovorax citrulli, a tatB disruption mutantstrain △tatB and its complementary strain CtatB were constructed by homologous recombination, and 6 factors （virulence, motility, growth ability, extracellular polysaccharide and cellulase producing ability and biofilmformation） were tested to illustrate Tat system＇s influence on Acidovorax citrulli. Comparing the expression of TrbC, hrcN, Aave_1810, Aave 0034 and hrpE genes by Real-time fluorescent quantitative PCR, to explorethe relationship between tatB gene and type Ⅲ secretion system, Tat system related genes and cell toxicity related genes. △tatB could trigger the hypersensitive response in non-host plant tobacco（Nicotiana tabacum）.The deficiency of tatB weakened Acidovorax citrulli＇s virulence, motility and growth ability, while had no effect on the production of extracellular polysaccharide （EPS）, extracellular cellulase and biofilm formation.Real-time fluorescent quantitative PCR analysis showed that the deficiency of tatB made the expressions of TrbC and hrcN genes in mutant strain significantly increased, while the expressions of other 3 genes notablydecreased. Consequently, the deficiency of functional gene tatB in Tat system affected some biological characteristics ofAcidovorax citrulli, and resulted in the decrease of pathogenic ability. These results supplybasic information for pathogenicity and protein secretion research apart from secretion systemⅢ.

关 键 词：双精氨酸转运系统 西瓜嗜酸菌 tatB基因 

分 类 号：S881.2[农业科学—特种经济动物饲养]