梨火疫菌(Erwinia amylovora)环腺苷酸受体蛋白基因(crp)的功能分析  

Functional Characterization of Cyclic Adenosine Monphosphate(cAMP) RecptorProtein Gene(crp) from Erwinia amylovora

作　　者：刘倩倩[1] 于洋洋[1] 宋俊贤[1] 胡白石[1] 范加勤[1] 刘凤权[1] 

机构地区：[1]南京农业大学农业部病虫监测与治理重点开放实验室,南京210095

出　　处：《农业生物技术学报》2010年第5期827-835,共9页Journal of Agricultural Biotechnology

基　　金：国家重点基础研究发展规划(973)项目(No.2009CB119202)资助

摘　　要：梨火疫菌(Erwinia amylovora)可引起梨、苹果等蔷薇科(Rosaceae)植物的火疫病。在菊欧文氏菌(Erwinia chrysanthemi)中,由crp基因编码的环腺苷酸受体蛋白(cyclic adenosine monphosphate(cAMP)receptor protein,CRP)对果胶酶基因的表达调控和菌株致病性起着重要的作用。本研究首次鉴定并克隆出梨火疫菌中的crp同源基因,命名为Eacrp,并通过同源重组的方法,构建了梨火疫菌的crp基因突变体EaΔcrp以及互补子,进行了致病性、过敏性反应、胞外多糖、鞭毛运动等一系列相关表型的鉴定。结果表明,crp基因影响着梨火疫菌的致病性、胞外多糖、游动性、生长情况等多种生物学特性,然而,EaΔcrp仍能引起烟草过敏性反应,并且在过氧化氢敏感度以及沉降性、生物膜和AI-2信号分子的生成方面与野生型菌株相比差异明显。本研究结果说明,梨火疫菌crp基因对病菌的胞外多糖分泌、生长、游动性以及致病性方面具有关键作用。Erwinia amylovora causes fire blight of pear,apple,and many of the Rosaceae family.The cyclic adenosine monphosphate（cAMP） receptor protein（CRP）,which is encoded by crp gene,plays a crucial role in expression of the pectinolysis genes and regulation of the pathogenicity in Erwinia chrysanthemi.In this study,the homolog of crp gene,designated Eacrp,was identified and cloned in Erwinia amylovora.A crp disruption mutant EaΔcrp was successfully generated by homologous recombination.Complement strain EaΔcrp（pME-crp） was also constructed.Then crp gene was characterized to virulence,hypersensitive response（HR）,extracellular polysaccharide（EPS）,motility and otherphenotypes of the phytopathogens Erwinia amylovora.The results showed that the crp mutant EaΔcrp displayed the reduced virulence,EPS production and growth in vitro and motility.However,compared to wild type strain NCPPB1665（Ea1665）,the induction of HR in nonhost tobacco,peroxide resistance,sedimentation,biofilm synthesis and AI-2 production of the crp mutant EaΔcrp was not affected.These findings demonstrated that crp gene in Erwinia amylovora is involved in EPS production,growth,and motility and play an important role in virulence.

关 键 词：梨火疫菌 crp基因 致病性 胞外多糖 

分 类 号：S436.612.1[农业科学—农业昆虫与害虫防治]