青枯菌4号生理小种Ⅲ型分泌系统新效应子鉴定及其功能分析

Ginger bacterial wilt caused by Ralstonia solanacearum Race 4 was a devastating disease on ginger and Rhizoma Kaempferiae in China. The type III system-secreted effector plays a most important role in R. solanacearum pathogenicity. Genome sequencing, gene function annotation and gene functional verification of R. solanacearum Race 4 strain YC45 were completely finished. Five new genes encoding putative T3SS effector were found by genome bioinformatics analysis. In this study, qRT-PCR and adenylate cyclase assay were used to identify the five T3SS putative effectors. Gene deleted mutant strain and its complementary strain are constructed by gene homologous recombination, biochemical characteristics test, pathogenicity colonization in host plant and changes in enzyme content assay are carried out between wide strain, gene deleted mutant strain and its complementary strain, which will be helpful for us to understand the new gene function. Results of this study will be useful in revealing pathogenesis of R. solanacearum race 4, which will facilitate the development of effective control measures against bacterial wilt.This project has important scientific significance and application prospects.

茄科青枯菌4号生理小种侵染引起的姜瘟是我国生姜和沙姜等作物上毁灭性病害。由Ⅲ型分泌系统（T3SS）分泌的效应子是茄科青枯菌致病的主要决定因子之一。申请人团队已完成了对茄科青枯菌4号生理小种YC45菌株的基因组测序、基因功能注释及部分基因功能验证，通过生物信息学分析,还获得了5个T3SS候选新效应子。本项目拟在已取得的进展基础上，利用qRTPCR和腺苷酸环化酶转导试验，对5个T3SS候选新效应子进行鉴定；应用基因同源重组方法,构建新效应子基因的突变菌株及其互补菌株，测定其生物学特性、致病性、寄主体内定殖特性及对寄主体内酶类含量变化影响等,探明新效应子的功能。研究结果将有助于对茄科青枯菌4号生理小种致病机理的认识，并为探索姜瘟防控新技术奠定基础，本项目具有重要的科学意义和应用前景。

茄科青枯菌4号生理小种侵染引起的姜瘟是我国生姜和沙姜等作物上毁灭性病害。由Ⅲ型分泌系统（T3SS）分泌的效应子是茄科青枯菌致病的主要决定因子之一。利用qRT-PCR，筛选出青枯菌4号生理小种YC45菌株潜在效应子基因1个；应用同源重组的方法构建了YC45 4个基因ACH51_19605、ACH51_07235、ACH51_01905和ACH51_14495的突变菌株以及3个基因ACH51_19605、ACH51_01905和ACH51_14495的互补菌株。明确了ACH51_19605基因影响青枯菌YC45菌株的生长、胞外多糖分泌、生物膜形成及其致病性，但不影响YC45菌株的运动性；ACH51_07235基因影响青枯菌YC45菌株的生长、胞外多糖分泌及其致病性，但不影响YC45菌株的生物膜形成和运动性；ACH51_01905基因不影响青枯菌YC45菌株的生长、胞外多糖分泌、生物膜形成、运动性及其致病性；ACH51_14495基因影响青枯菌YC45菌株的生长，但不影响YC45菌株的胞外多糖分泌、生物膜形成、运动性及其致病性。研究结果将有助于对茄科青枯菌4号生理小种致病机理的认识，并为探索姜瘟防控新技术奠定基础。