7月3日，《美国国家科学院院刊》（PNAS）在线发表了由中国科学院微生物研究所刘杏忠研究员和University of Texas的安志强教授共同领导的研究团队在捕食性子囊菌起源与进化方面所取得的新进展。
捕食性真菌是通过营养菌丝形成的特化捕食结构来捕获线虫、变形虫等微小生物作为营养源的一类特殊来群。由于其独特的生态特性，捕食性真菌的起源与进化引起了科学界的广泛兴趣。在2007年，由刘杏忠研究员和安志强教授共同领导的研究团队对捕食性子囊菌（占捕食性真菌的90%以上）捕食结构的进化历程作出较为详细的论证，发现原始捕食结构由于捕食机制的不同，分别形成了主动类的收缩环捕食结构和被动类的粘性捕食结构（PNAS 104：8379）。随后，SCIENCE（318：1743， 2010）报道了一种已灭绝捕食结构的真菌化石。Duke University的Heitman教授认为这两项研究为研究捕食性真菌的系统发育铺平了道路（ Faculty of 1000：1098524）。
在前期工作的基础上，刘杏忠研究员和安志强教授领导的研究团队通过对精心选择的、代表6种捕食结构的 16种捕食性子囊菌的5个蛋白质编码基因片段进行分析，结合相关的化石证据和分子钟计算，推测捕食性子囊菌的祖先可能起源于4.19亿年前；在2.46亿年前，主动类的收缩环捕食结构和被动类的粘性捕食结构发生分化；而粘性捕食结构在1.98-2.08亿年之间快速分化并形成现存捕食结构的主要分支。而基于捕食结构为收缩环的Drechslerella stenobrocha基因组数据，通过独立的时间校正点对1069个同源蛋白序列分析，推测主动类的收缩环捕食结构和被动类的粘性捕食结构的分化事件在2.60亿年前，与上述分析结果高度接近。
由于捕食性子囊菌两次重大分化事件的发生事件接近于2.51亿年前的二叠纪-三叠纪物种大灭绝事件和2.01亿年前的三叠纪-侏罗纪物种大灭绝事件，研究团队进而推测物种大灭绝所导致的大量有机物，促使线虫大量繁衍，而真菌为了获取氮源以及在恶劣环境压力胁迫下，可能驱动了子囊菌捕食能力的进化。该研究为真菌在极端环境下的适应性进化提供了新的理论。（生物谷Bioon.com）
doi:10.1073/pnas.1120915109
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Origin and evolution of carnivorism in the Ascomycota (fungi)
Ence Yanga,1, Lingling Xua,b,1, Ying Yanga, Xinyu Zhanga, Meichun Xianga, Chengshu Wangc, Zhiqiang And,2, and Xingzhong Liua,2
Carnivorism is one of the basic life strategies of fungi. Carnivorous fungi possess the ability to trap and digest their preys by sophisticated trapping devices. However, the origin and development of fungal carnivorism remains a gap in evolution biology. In this study, five protein-encoding genes were used to construct the phylogeny of the carnivorous fungi in the phylum Ascomycota; these fungi prey on nematodes by means of specialized trapping structures such as constricting rings and adhesive traps. Our analysis revealed a definitive pattern of evolutionary development for these trapping structures. Molecular clock calibration based on two fossil records revealed that fungal carnivorism diverged from saprophytism about 419 Mya, which was after the origin of nematodes about 550–600 Mya. Active carnivorism (fungi with constricting rings) and passive carnivorism (fungi with adhesive traps) diverged from each other around 246 Mya, shortly after the occurrence of the Permian–Triassic extinction event about 251.4 Mya. The major adhesive traps evolved around 198–208 Mya, which was within the time frame of the Triassic–Jurassic extinction event about 201.4 Mya. However, no major carnivorous ascomycetes divergence was correlated to the Cretaceous–Tertiary extinction event, which occurred more recently (about 65.5 Mya). Therefore, a causal relationship between mass extinction events and fungal carnivorism evolution is not validated in this study. More evidence including additional fossil records is needed to establish if fungal carnivorism evolution was a response to mass extinction events.
