水稻细菌性条斑病菌中假定编码甲基趋化蛋白的基因的功能初步研究

Preliminary Functional Analysis of a Putative Encoded Gene of Methyl-accepting Chemotaxis Protein in Xamthomonas. oryzae pv. oryzicola

水稻细菌性条斑病菌(Xamthomonas.oryzae pv.oryzicola,Xoc)是水稻的主要病原菌之一,其引发的水稻细菌性条斑病可造成水稻严重减产。本文利用水稻细菌性条斑病菌广西分离株GX01作为实验菌株,获得XOC2233基因的Tn5插入突变体,XOC2233编码为假定的甲基受体趋化性蛋白,本实验对其生化表型以及致病性的研究表明,突变体的致病力与野生型相比没有明显变化,但其胞外多糖产量和游动性增强,且其胞外蛋白酶的活性有所降低,而互补菌株均能恢复其表型到野生型水平。根据本研究的结果推测XOC2233基因可能通过对鞭毛的合成控制影响胞外多糖的分泌,为进一步研究XOC2233基因在水稻条斑病菌胞外多糖代谢途径中的作用提供了基础。

Xamthomonas. oryzae pv. oryzicola(Xoc), the causal agent of rice bacterial leaf streak, is one of the most serious diseases of rice. It can cause a severe reduction of rice output. In this study, using Xoc GX01 isolated from Guangxi as experimental strain, XOC2233 gene was obtained by Tn5 insertion, XOC2233 coding for assuming methyl-accepting chemotaxis protein. According to the biochemical phenotype and pathogenicity assays, mutant does not affect the pathogenicity of Xoc in rice, but the extracellular polysaccharide yield and swimming ability are enhanced, and the extracellular protease activity decreased, while the complementary strain could recover the phenotypes to the level of wild type. The result suggests that XOC2233 gene may influence the secretion of extracellular polysaccharide by controlled the synthesis of flagella. This result provides the basis for the further study of XOC2233 gene in extracellular polysaccharide metabolism pathway of Xanthomonas oryzae pv. oryzicola.