黄瓜黑星病菌核糖体基因ITS区段的克隆及序列分析

为了探讨枝孢霉属的系统发育情况,采用真菌核糖体基因转录间隔区域(ITS)通用引物,PCR扩增3株来自不同地方的黄瓜黑星病菌核糖体基因的ITS序列,并对PCR产物进行测序和序列分析。结果表明:3株黄瓜黑星病菌之间同源性为100%,ITS全长463bp,其中ITS1长154bp,5.8S rDNA长159bp,ITS2长150bp,各碱基的个数分别为G 119个、C 118个、A 120个、T 106个,GC含量为51.2%。利用MEGA4软件中的NJ法和ME法,对3个样品序列以及GenBank中登陆的枝孢霉属其他25个种构建ITS聚类分析树状图,NJ法和ME法构建的结果基本相同,枝孢霉属可以分为5个聚类组,所测的3个样品和Cladosporium cucumerinum在一个聚类组中。

Cloning and Sequencing of Ribosomal RNA ITS Regions in Cladosporium cucumerinum

The aim of the research was to explore the phylogenetic correlations among the strains of Cladosporium spp.The internal transcribed spacer regions(ITS) of the ribosomal RNA gene from Cladosporium cucumerinum were amplified with the polymerase chain reaction through the universal primers and sequenced.The resulted size of total length was 463bp,5.8S was 159bp and ITS2 was 150bp.The number of A,T,G and C was 120,106,119 and 118 respectively and GC content was 51.2%.Based on the three sequences and another published sequences of 25 species of Cladosporium spp.In Gen Bank database,the ITS phylogenetic trees were generated with the soft of Mega 4.The results showed approximately consistent between NJ tree and ME tree.It suggested that the Cladosporium spp.was divided into 5 groups.The three samples tested and C.cucumerinum were formed in the same group.In conclusion,the phylogenetic analysis of ITS sequence could provide the important reference basis for the genus identification of Cladosporium spp.