虫草属线粒体基因组特征及系统发育  

Mitogenome characteristics and evolution of Cordyceps

作　　者：韩利红 柯欣茹 秦相月 普琪 任怡园 刘潮 HAN Li-hong;KE Xin-ru;QIN Xiang-yue;PU Qi;REN Yi-yuan;LIU Chao(College of Biological Resource and Food Engineering,Yunnan Engineering Research Center of Fruit Wine,Qujing Normal University,Qu-jing,Yunnan 655011,China)

机构地区：[1]曲靖师范学院生物资源与食品工程学院/云南省高校特色果酒技术创新与应用工程研究中心,云南曲靖655011

出　　处：《西南农业学报》2022年第7期1520-1528,共9页Southwest China Journal of Agricultural Sciences

基　　金：国家自然科学基金(32100010;31860005);云南省地方本科高校基础研究联合专项(202001BA070001-002)。

摘　　要：【目的】很多虫草属(Cordyceps)物种含有丰富的虫草素、多糖、喷司他丁等有效成分,具有重要的医疗保健功效和开发利用价值。研究虫草属线粒体基因组特征及系统发育,为虫草科真菌物种的起源与进化、资源保护和开发利用提供借鉴。【方法】基于9种虫草菌线粒体基因组序列,利用MEGA、REPuter、MISA、mVISTA和PAML等生物信息学软件,对线粒体基因组特征、序列重复、结构变异、基因进化和系统发育进行分析。【结果】虫草属物种线粒体基因组大小差异明显,均含有15个蛋白编码基因、2个rRNA和至少25个tRNA;物种重复序列数目差异较大,多为正向重复和回文重复,SSR主要为二核苷酸、三核苷酸和四核苷酸重复,且含有较高比例的A或T碱基;线粒体基因组结构高度相似,未发现基因重排现象,线粒体基因组大小和内含子长度呈线性正相关;基因rps3核苷酸变异程度较高,所有基因的dN/dS比率均小于1,nad4、rps3、cob、nad2和cox1等基因存在正选择位点;粗糙虫草和粉质虫草聚类关系较近,而细脚虫草、蝉棒束孢和蝉花虫草聚在一起。【结论】虫草属物种线粒体基因组结构保守,基因组大小主要受内含子影响,蛋白编码基因主要受纯化选择作用,部分基因在与宿主和环境互作过程中受到了轻微的选择作用。【Objective】 Multiple species of Cordyceps contain a high concentration of cordycepin, polysaccharide, pentostatinand other effective components, which have important medical and health care efficacy and development and utilization value. The mitogenome characteristics and evolution of Cordyceps were studied to provide a reference for the origin and evolution, resource protection, development and utilization of Cordyceps fungi.【Method】 Based on the mitogenome sequences of nine Cordyceps species, the characteristics, sequence repeats, structural variation, gene evolution and phylogeny of mitogenome were analyzed by using bioinformatics analysis software, such as MEGA, Reputer, MISA, mVISTA and PAML. 【Result】 There were significant differences in mitogenome size among nine Cordyceps species, and all containcoding genes for 15 protein coding genes, two rRNAs and at least 25 tRNAs. The number of repeats varied greatly among species, which mostly were forward repeats and palindromic repeats. SSRs were mainly of dinucleotide, trinucleotide and tetranucleotide repeats, and contained a high proportion of A or T bases. The structure of mitogenome was highly similar among all species, and no gene rearrangement was found. There was a linear positive correlation between mitogenome size and intron length. The nucleotide variation of rps3 gene was high, and the dN/dS ratio of all genes was less than one. There were positive selection sites in nad4, rps3, cob, nad2 and cox1 genes. C. confragosa and C. farinosa were closely related, whereas C. tenuipes, C. cicadae and C. chanhua gather together. 【Conclusion】 The mitogenome structure of Cordyceps was conservative, the genome size was mainly affected by introns, the protein coding genes were mainly affected by purification selection, and some genes were slightly selected in the process of interaction with the host and the environment.

关 键 词：虫草属 线粒体基因组 进化 变异 

分 类 号：Q931[生物学—微生物学]