Degrassi Giuliano, Devescovi Giulia, Kim Jinwoo, Hwang Ingyu, Venturi Vittorio
Bacteriology Group, International Centre for Genetic Engineering and Biotechnology, Padriciano, Trieste, Italy.
FEMS Microbiol Ecol. 2008 Aug;65(2):251-62. doi: 10.1111/j.1574-6941.2008.00516.x. Epub 2008 Jul 9.
Burkholderia glumae is an emerging seed-borne rice pathogen in many areas around the world. Previous studies have demonstrated that B. glumae produces two major virulence factors: the phytotoxin toxoflavin and a secreted lipase. This synthesis of both of these factors is regulated by an N-acyl homoserine lactone (AHL)-dependent, cell-density-dependent quorum-sensing regulation system. This study reports the production and secretion of two highly similar endo-polygalacturonases (designated PehA and PehB) by B. glumae. The two enzymes were purified to homogeneity and the corresponding genetic determinants were identified and characterized. When either polygalacturonase gene was inactivated, B. glumae retained rice virulence comparable to that of the wild-type parent strain. Furthermore, the role of AHL-dependent quorum sensing and of plant cell wall degradation compounds in their regulation was investigated.
稻瘟病菌是世界许多地区新出现的一种种传水稻病原菌。先前的研究表明，稻瘟病菌产生两种主要的毒力因子：植物毒素毒黄素和一种分泌型脂肪酶。这两种因子的合成受N-酰基高丝氨酸内酯（AHL）依赖性、细胞密度依赖性群体感应调节系统调控。本研究报道了稻瘟病菌产生并分泌两种高度相似的内切多聚半乳糖醛酸酶（命名为PehA和PehB）。将这两种酶纯化至同质，并对相应的遗传决定因素进行了鉴定和表征。当任一多聚半乳糖醛酸酶基因失活时，稻瘟病菌对水稻的毒力与野生型亲本菌株相当。此外，还研究了AHL依赖性群体感应和植物细胞壁降解化合物在其调控中的作用。
