桑青枯病病原G12-9内切葡聚糖酶基因的克隆和分类

桑青枯病是一种土传性细菌病害，从广东省桑园发生青枯病的桑树根部分离得到1株病原菌G12-9；经鉴定确定该菌为青枯菌（Ralstonia solanacearum），该病原菌在TZC固体培养基上呈圆形及不规则圆形，菌落中央呈现淡红色，革兰氏染色成阴性。对G12-9分离株内切葡聚糖酶基因的克隆、序列测定及聚类分析结果表明，桑青枯菌G12-9内切葡聚糖酶属于糖基水解酶家族12。青枯菌最重要的致病性分泌系统为Ⅱ、Ⅲ、Ⅳ型分泌系统，内切葡聚糖酶属于细菌Ⅱ型分泌系统，内切葡聚糖酶对于青枯菌的定植及寄主植物的致病性有着非常重要的作用，明确该酶在糖基水解酶家族的分类地位对桑青枯病的防治具有重要意义。

Clone and Classification of Endoglucanase Gene of Mulberry Bacterial Wilt Pathogen G12-9

Mulberry bacterial wilt pathogen is a soilborne bacterial disease,a pathogen G12-9 was isolated from the root of mulberry which was infected bacterial wilt plant disease from mulberry field in Guangdong province. This pathogen on TZC solid medium was rounded or irregular round, the colony center color showed pink. It was a negative Gram strain. By endoglucanase gene within G12- 9 isolate cloning, sequencing and cluster analysis, mulberry Ralstonia solanacearum G12-9 endoglucanase belonging to glycosyl hydrolase family 12. The most important pathogenicity secretion system in R. solanacearum are Ⅱ ,Ⅲ , Ⅳ, endoglucanase belongs to T2S. It plays an important role on colonization and host infection, so it is very significant for the disease prevention and treatment by clearing mulberry R. solanacearum endoglucanase position in the classification of glycosyl hydrolase family.