近日，中科院上海生科院植生生态所王成树课题组关于蛹虫草基因组的研究取得进展，相关文章发表在Genome Biology上，为深入研究虫草活性成分代谢途径及其有性生殖的分子调控机理等奠定了良好的基础。
能够感染杀虫的真菌种类达1000多种，主要为子囊菌。以绿僵菌和白僵菌等为代表的昆虫病原真菌已被开发为环境友好的真菌杀虫剂；以冬虫夏草和蛹虫草（又称北虫草、北冬虫夏草）等为代表的昆虫病原真菌具有良好的医药保健功能。进化基因组分析表明蛹虫草的出现较绿僵菌早约1.3亿年，各自独立进化而具有杀虫特性，但表现出协同进化的特点：与其他真菌相比，蛋白酶和几丁质酶等用于昆虫体壁降解的蛋白质家族表现出明显的扩张现象。基因组分析表明，蛹虫草基因组大约有16%的编码基因参与真菌—昆虫的相互作用，不存在编码对于人类有害的已知真菌毒素。首次表明蛹虫草有性生殖类型为异宗配合，但单交配型菌株能够结实。此外，与其他真菌不同，其子实体发育主要受MAPK信号途径调控，而非MAPK和PKA共同调控。
这是该课题组完成绿僵菌比较基因组研究后(PLoS Genetics, 2011)，关于昆虫真菌基因组研究的又一成果。该项研究获得了创新2020、上海市科委及973等项目支持。（生物谷Bioon.com）
doi:10.1186/gb-2011-12-11-r116
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Genome sequence of the insect pathogenic fungus Cordyceps militaris, a valued traditional Chinese medicine
Peng Zheng, Yongliang Xia, Guohua Xiao, Chenghui Xiong, Xiao Hu, Siwei Zhang, Huajun Zheng, Yin Huang, Yan Zhou, Shengyue Wang, Guo-Ping Zhao, Xingzhong Liu, Raymond J St Leger and Chengshu Wang
Species in the ascomycete fungal genus Cordyceps have been proposed to be the teleomorphs of Metarhizium species. The latter have been widely used as insect biocontrol agents. Cordyceps species are highly prized for use in traditional Chinese medicines, but the genes responsible for biosynthesis of bioactive components, insect pathogenicity and the control of sexuality and fruiting have not been determined. Here, we report the genome sequence of the type species C. militaris. Phylogenomic analysis suggests that different species in the Cordyceps/Metarhizium genera have evolved into insect pathogens independently of each other, and that their similar large secretomes and gene family expansions are due to convergent evolution. However, relative to other fungi including Metarhizium spp., many protein families are reduced in C. militaris, which suggests a more restricted ecology. Consistent with its long track record of safe usage as a medicine, the Cordyceps genome does not contain genes for known human mycotoxins. We establish that C. militaris is sexually heterothallic but, very unusually, fruiting can occur without an opposite mating-type partner. Transcriptional profiling indicates that fruiting involves induction of the Zn2Cys6-type transcription factors and MAPK pathway; unlike other fungi, however, the PKA pathway is not activated.
