Key Laboratory of Insect Developmental and Evolutionary Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
Genome Biol. 2011 Nov 23;12(11):R116. doi: 10.1186/gb-2011-12-11-r116.
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 Cordyceps 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.
The data offer a better understanding of Cordyceps biology and will facilitate the exploitation of medicinal compounds produced by the fungus.
子囊菌真菌虫草属中的物种被提议为绿僵菌物种的同形物。后者已被广泛用作昆虫生物防治剂。虫草属物种因其在传统中药中的应用而备受推崇，但负责生物活性成分合成、昆虫致病性以及控制性别和果实形成的基因尚未确定。
在这里，我们报告了模式种蛹虫草的基因组序列。系统发育分析表明，虫草属/绿僵菌属中的不同物种已独立进化为昆虫病原体，它们相似的大型分泌组和基因家族扩张是由于趋同进化。然而，与其他真菌（包括绿僵菌）相比，蛹虫草中的许多蛋白质家族减少，这表明其生态环境更为受限。与作为药物安全使用的悠久历史相一致，虫草属基因组不包含已知的人类真菌毒素基因。我们确定蛹虫草是有性异宗配合的，但非常不寻常的是，在没有相反交配型伴侣的情况下也能发生果实形成。转录谱分析表明，果实形成涉及 Zn2Cys6 型转录因子和 MAPK 途径的诱导；然而，与其他真菌不同，PKA 途径没有被激活。
这些数据提供了对虫草属生物学的更好理解，并将有助于开发真菌产生的药用化合物。
