变灰青霉线粒体基因组特征及系统发育分析

Characterization of the complete mitochondrial genome and phylogenetic analysis of Penicillium canescens

本研究对一株分离自细虫草上的变灰青霉SFY00C3菌株线粒体基因组进行测定,分析其组成特征,并探究其与青霉属真菌的系统发育关系。结果表明,SFY00C3的线粒体基因组是一条长度为28301 bp的环状DNA分子,共编码42个基因(15个蛋白编码基因、2个rRNA基因和25个tRNA基因),其碱基组成有显著的A-T偏好性,25个tRNA基因均可形成典型三叶草结构,并存在32处G-U错配。通过青霉属物种间共线性分析发现其线粒体基因组发生了基因重排;共有的14个蛋白编码基因的Ka/Ks值均小于1,表明受到了纯化选择压力的影响;系统发育分析表明:SFY00C3在青霉属中是一个独立的分支,应该是6种青霉祖先的姊妹。本研究丰富了变灰青霉的线粒体基因组序列信息,为青霉属的系统发育、资源保护及遗传多样性研究提供基础数据。

The mitochondrial genome of Penicillium canescens SFY00C3 isolated from Ophiocordyceps gracilis was determined and its composition characteristics were analyzed.The phylogenetic relationship between the genome and Penicillium species was explored.The results showed that the mitochondrial genome of P.canescens SFY00C3 was a circular DNA molecule with a length of 28 301 bp,encoding 42 genes(15 protein coding genes,2 rRNA genes and 25 tRNA genes).Its base composition had significant A-T bias.All of the 25 tRNA genes could form a typical cloverleaf structure with 32 G-U mismatches.Gene rearrangement of mitochondrial genome was found by collinearity analysis among Penicillium species.The Ka/Ks values of 14 protein coding genes were less than 1,indicating that they were subjected to purification selection pressure.Phylogenetic analysis showed that SFY00C3 was an independent branch in Penicillium and should be the sister of the ancestors of six species of Penicillium.This finding enriched the mitochondrial genome sequence information of P.canescens,and provided basic data for phylogenetic analysis,resource protection and genetic diversity of Penicillium.