Zhang Yong-Jie, Fan Xiang-Ping, Li Jia-Ni, Zhang Shu
School of Life Science, Shanxi University, Taiyuan, 030006, China.
Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan, 030006, China.
IMA Fungus. 2023 Jul 6;14(1):13. doi: 10.1186/s43008-023-00118-5.
Cordyceps is a diverse genus of insect pathogenic fungi, with about 180 accepted species, including some well-known ones used as ethnic medicine and/or functional food. Nevertheless, mitogenomes are only available for four members of the genus. The current study reports the mitogenome of Cordyceps blackwelliae, a newly described entomopathogenic fungus. The 42,257-bp mitogenome of the fungus encoded genes typically found in fungal mitogenomes, and a total of 14 introns inserted into seven genes, including cob (1 intron), cox1 (4), cox3 (3), nad1 (1), nad4 (1), nad5 (1), and rnl (3). RNA-Seq analysis revealed differential expression of mitochondrial genes and supported annotations resulting from in silico analysis. There was clear evidence for polycistronic transcription and alternative splicing of mitochondrial genes. Comparison among mitogenomes of five different Cordyceps species (i.e., C. blackwelliae, C. chanhua, C. militaris, C. pruinosa, and C. tenuipes) revealed a high synteny, with mitogenome size expansion correlating with intron insertions. Different mitochondrial protein-coding genes showed variable degrees of genetic differentiation among these species, but they were all under purifying selection. Mitochondrial phylogeny based on either nucleotide or amino acid sequences confirmed the taxonomic position of C. blackwelliae in Cordycipitaceae, clustering together with C. chanhua. This study promotes our understanding of fungal evolution in Cordyceps.
虫草属是一类多样的昆虫病原真菌，约有180个公认的物种，包括一些用作民族药物和/或功能性食品的知名品种。然而，目前仅获得了该属四个成员的线粒体基因组。本研究报告了新描述的昆虫病原真菌——布莱克韦尔虫草的线粒体基因组。该真菌42,257 bp的线粒体基因组编码了真菌线粒体基因组中常见的基因，共有14个内含子插入到7个基因中，包括细胞色素b（cob，1个内含子）、细胞色素c氧化酶亚基1（cox1，4个）、细胞色素c氧化酶亚基3（cox3，3个）、烟酰胺腺嘌呤二核苷酸脱氢酶亚基1（nad1，1个）、烟酰胺腺嘌呤二核苷酸脱氢酶亚基4（nad4，1个）、烟酰胺腺嘌呤二核苷酸脱氢酶亚基5（nad5，1个）和大核糖体亚基RNA（rnl，3个）。RNA测序分析揭示了线粒体基因的差异表达，并支持了基于计算机分析的注释。有明确证据表明存在多顺反子转录和线粒体基因的可变剪接。对五个不同虫草物种（即布莱克韦尔虫草、蝉花虫草、蛹虫草、粉被虫草和细脚虫草）的线粒体基因组进行比较，发现它们具有高度的共线性，线粒体基因组大小的扩展与内含子插入相关。不同的线粒体蛋白质编码基因在这些物种之间表现出不同程度的遗传分化，但它们都受到纯化选择。基于核苷酸或氨基酸序列的线粒体系统发育分析证实了布莱克韦尔虫草在虫草科中的分类地位，它与蝉花虫草聚在一起。本研究增进了我们对虫草属真菌进化的理解。
