油菜菌核病菌(Sclerotinia sclerotiorum)与细菌间的基因水平转移  

Horizontal Gene Transfer Between Sclerotinia sclerotiorum and Bacteria

作　　者：吕林峰[1] 岳建宇[1] 费忠安[1] 赵锐[1] 乔代蓉[1] 曹毅[1] 

机构地区：[1]四川大学生命科学学院四川省生物信息与代谢工程共享实验平台,成都610064

出　　处：《应用与环境生物学报》2012年第1期42-48,共7页Chinese Journal of Applied and Environmental Biology

基　　金：国家"973"项目(No.2009CB125910);四川省"十一五"支撑计划项目(Nos.2008GZ0020;2008GZ0021)资助~~

摘　　要：油菜菌核病(Sclerotinia sclerotiorum)是油菜生产上最重要的病害之一,其致病性可能来源于基因水平转移(Horizontal gene transfer,HGT).为认识其致病原理和寻找新的真菌抑制剂的靶点,首先通过BLASTp发现其基因XM_001585458.1编码蛋白XP_001585508.1与细菌比对结果中出现低E值3.23e-109和高SCORE值436,暗示存在HGT现象;进一步通过系统进化树的建立,发现该蛋白在进化分枝上更接近于细菌中由Streptomyces sp.C的NZ_CM000832.1基因编码的蛋白ZP_07291173;同时核苷酸组成分析也发现该基因与油菜菌核病菌基因组的碱基组成有较大差别,GC含量提高了14.95%.这些结果证明了XM_001585458.1的确存在基因水平转移事件.结构分析和COG蛋白功能分类显示该HGT序列编码蛋白XP_001585508.1具有FA58C_3(Coagulation factors 5/8 type C domain)、Kelch repeat type 1、Galactose-binding domain-like、Galactose oxidase/kelch,beta-propeller等保守结构域,应为一个膜蛋白并参与多糖代谢,推测该水平转移基因与S.sclerotiorum在侵染植物时进行细胞壁水解和致病性有关.Sclerotinia sclerotiorum is one of the most terrible diseases for rapeseeds in production.Its pathogenicity may probably get from horizontal gene transfer（HGT）.For understanding its pathogenic mechanism and finding targets for new fungal inhibitors,firstly in BLASTp comparison results of gene XM_001585458.1-coded proteins XP_001585508.1 of different species,low E value 3.23e-109 and high SCORE value 436 appeared in the results of bacteria,showing HGT happened probably.Then via phylogenetic method,gene XM_001585458.1 was found out the closest to bacterium.At the same time,by nucleotide composition analysis,XM_001585458.1 also appeared quite different from the genome of S.sclerotiorum,since GC-content increased 14.95%.To sum up,HGT of gene XM_001585458.1 was found out.And structure and COG analysis indicated that there were two distinct transmembrane domains in 14~171 and 465~485 of protein XP_001585508.1,and this protein also consisted of 6 β-sheets,1 α-helix,some turns,and random coils.So the candidate protein encoded by the transferring gene should be further predicted to be a membrane protein participating in polysaccharide metabolic.And it can be assumed that the gene transferring is related to the pathogenicity of S.sclerotiorum and its activity of hydrolyzing the cell wall when it is infecting the plant.

关 键 词：基因水平转移 油菜菌核病 系统发生树 碱基组成 

分 类 号：S435.654[农业科学—农业昆虫与害虫防治] Q933[农业科学—植物保护]