植物病原细菌 hrp 基因簇比较基因组分析

摘要

hrp基因是植物病原细菌中一类重要的致病基因，一般成簇排列。对14种已完成全基因组测序的植物病原细菌基因组中的hrp基因簇进行了大小、G＋C含量、基因组成的BlastP比较。发现它们的大小在18～24 kb，由22～28个基因组成。欧文氏菌属和假单胞菌属的菌株中G＋C含量较低，拉尔氏菌属和黄单胞菌属菌株的G＋C含量较高。而且，各菌属的基因簇都有其独有的hrp基因，如假单胞菌属是hrpK1、hrpV、hrpA；欧文氏菌属是hrpT、hrpV、hrpA；拉尔氏菌属是hrpZ、hrpX、hrpY、hrpV；黄单胞菌属是hrpE、hrpD6、hpaA。其中，基因hrpA1、hrpA、hrpY和hrpE在假单胞菌属、欧文氏菌属、拉尔氏菌属和黄单胞菌属中均编码Ⅲ型菌毛的基因，可能在寄主和病原物识别中起重要作用。%hrp gene is one of important pathogenity genes in phytopathogenic bacteria ,usually in cluster.The size,G+C contents and BlastP of the constituted genes of 14 completed sequenced phytopathogenic bacterias in this article compare.It find that these size of gene clusters among 18-24 kb,made up by 22-28 genes.The G+C con-tents is lower in the Pseudomonas and Erwinia genus,but higher in the Xanthomonas and Ralstonia genus.Moreo-ver,every genus has its own unique hrp gene cluster,such as in the Pseudomonas are hrpZ1 ,hrpA1 ,hrpV genes.In the Erwinia genus are hrpT,hrpV,hrpA genes.In the Ralstonia genus are hrpZ,hrpX,hrpY,hrpV genes.In the Xan-thomonas are hrpE,hrpD6 ,hpaA.Among these genes,hrpA1 ,hrpA,hrpY,hrpE respectively belong to Pseudomonas spp,Erwinia spp,Ralstonia spp and Xanthomonas spp,encode type Ⅲ pilus,these genes maybe act as important function in pathogens recognize host progross .