【摘要】 本研究利用真菌核糖体基因转录间隔区(ITS)通用引物,PCR扩增四川省凉山州不同地区的20株烟草黑胫病菌的ITS序列,并对PCR产物进行了克隆测序。结果表明,20个供试菌株的ITS1-5.8S-ITS2总长均为803 bp;各菌株之间的ITS序列同源性达到99.3%以上;与Gen Bank报道的寄生疫霉台湾烟草分离株Phytophthora parasitica(GU111675.1)的同源性在99.6%~100%之间;但各菌株ITS序列的个别位点存在突变,这些突变主要集中在ITS2区上,其中第468处的突变具有一定地域性,主要为德昌和西昌的菌株。利用MEGA6软件对20个供试菌株及Gen Bank中登陆的15个疫霉属菌株序列进行聚类分析,供试菌株与Gen Bank上登录的GU111675.1、KF010303.1、AJ854295.1、KC768775.1、L41383聚在同一聚类组上,均为Phytophthora parasitica(或Phytophthora nicotianae),其它疫霉种聚在不同的聚类组上,遗传关系较远,这表明来自四川凉山不同地区的20株烟草黑胫病分离菌株均为寄生疫霉(Phytophthora parasitica)。更多还原

【Abstract】 The internal transcribed spacer regions(ITS) of the ribosomal RNA gene from 20 isolates of tobacco black shank were amplified with the polymerase chain reaction through the universal primers and sequence. The result showed that the total length of ITS of those 20 isolates tested were all 803 bp, and the nucleotide sequence identity among those sequences was above 99.3%, and 20 strains had 99.6%-100% homologies with Phytophthora parasitica(GU111675.1) published in Gen Bank. But the ITS of those 20 isolates tested had some mutation sites which mainly concentrated in the ITS2 area and 468 mutation of isolates, which mainly came from Dechang and Xichang had certain regional. With the bio-software of MEGA6, Sequences from the above isolates were compared with 15 sequences published in Gen Bank database and phylogenitic trees were constructed based on ITS sequence data. The results showed that the isolates tested, GU111675.1, KF010303.1, AJ854295.1, KC768775.1 and L41383 were clustered into the same clade and all were Phytophthora parasitica(or Phytophthora nicotianae). They were clustered in a distant clade for different Phytophthora species and phylogenetically distinct each other. The results indicated that twenty isolates which isolated from different regions of Liangshan prefecture were Phytophthora parasitica.更多还原