无性丝孢真菌典型属、种有性进化生态遗传机制研究

Most of hyphomycetes fungi are existed in anamorph, but all these fungi genera and speices contained a number of sexual genes including mating type genes, pheromone genes and α-genes of heterotrimeric G-proteins that manipulated sexual differentiation, development and evolution, which are similar to those in ascomycota fungi. The factors of environmental stress can regulate all those genes' expression effectiveness and even induce them to develop teleomorph. At the present study, we will carry out the study of ecology and heredity mechanism for sexual differentiation, development and evolution based on a part of typical species of Stemphylium and small spore of Alternara of dematiaceous hyphomycetes.1）Expound the diversity among three sexual genes, ratio of allotype mating type gene, relationship of phylogenetic development and the potential tendency of evolution;2) Analyze the regulation mechanisms among various sexual genes in different genera and species as well as adaption to the environmental stress, define the key sexual genes and suitable environment factors, and then predict the state of nature evolution among the genera and species based on the evolution character of earth habitat; 3) Prepare the mutant of knockout and complementation of key sexual genes that were isolated from typical amphiprotic species on the manipulation technique of gene, and elucidate the molecular mechanisms of sex and ecology for typical amphiprotic species as soon as integrate the relationship between phaenotype biology and regulation bioecology. All these results are possible to explain why most genera and species of hyphomycetes fungi are excited in anamorph, enrich the theory of fungi taxonomic study, and provide the theory supporting the rule of 'one fungi and one name'. All the expectation results will play a significant role in fungi taxonomic study.

绝大多数丝孢真菌属、种主要为无性型，但该类真菌含真子囊菌若干调控有性分化、发育及进化基因：交配型、信息素及G-蛋白α-亚基基因等。环境因子对该类真菌有性基因有效表达乃至发育为有性型具重要的调控作用。选取暗色丝孢科匍柄霉属、链格孢小孢子种及典型有性种，系统开展该类真菌有性分化、发育及其进化生态遗传机制研究：1）明确属、种有性基因成员多样性、异型交配基因比率、系统发育关系及有性进化潜力或趋势；2）分析属、种不同有性基因调控环境适应性机制，界定靶标基因及其适宜生态因子，结合地球生境演化特性，预测属、种有性特性自然演化历程；3）利用基因操作技术，制备两性种靶标基因敲除与互补突变体，分析表型生物学与调控生态学关系，阐明两性种有性分化分子生态调控机制。解析参试属、种主要为无性型的科学依据，丰富真菌分类研究的理论，为"一个真菌一个名称"命名法规提供理论支持，为真菌分类学做出重要的科学贡献。

针对绝大多数丝状子囊真菌绝大多数属、种为无性型的重大科学问题，以典型匍柄霉属、链格孢属及细基格孢属种菌为材料，以真菌关键有性调控基因为靶标，在正确测定和明确一典型丝状真菌有性种菌功能基因数量与类别基础上，系统开展了典型无性丝孢真菌属有性进化潜力与趋势研究，关键有性发育基因交配型基因(MAT）、G蛋白-α亚基基因、信息素前体基因Ste2和Ste3及组蛋白H3/H4分子伴侣Asf1基因调控典型无性丝状真菌有性发育遗传机制的研究。取得了系列创新性成果：1）解析和明确了一典型丝状子囊真菌匍柄霉有性型的全基因组信息及功能基因数量与类别，为准确克隆鉴定关键有性调控基因和开展无性丝状真菌有性发育机制研究提供了基因数据。2）探明了交配型基因适宜典型无性丝状真菌属级系统发育关系分析，预测并证实了无性丝孢真菌属、种交配型基因并未丧失有性进化性能，其种菌遗传背景限制了有性调控能力，证明了真菌异宗和同宗交配方式的非严格性，探明了典型无性丝孢真菌属、种具有性发育的潜力与趋势。3）探明了G蛋白-α亚基GPA1基因具调控典型丝状真菌种菌有性发育特性。4）首次探明了信息素前体Ste2和Ste3基因结构特征，证明了Ste2和Ste3基因通过与三个糖苷水解酶家族蛋白（GHF18、GHF32、及GFH128)互作，从而实现对无性丝状真菌有性发育调控性能，探明了Ste2和Ste3基因参与生物体丝裂原活化蛋白激酶通路（MAPK）通路途径，界定了MAPK通路途径新蛋白成员。5）克隆界定了参试种菌组蛋白H3/H4分子伴侣Asf1基因保守N-端和无序C-端结构特征，建立了参试种菌及其它丝状子囊真菌的Asf1基因系统发育关系，发现了Asf1基因通过与H4互作，而H4又与GTP结合蛋白和Dj-1家族蛋白特异性互作后，实现对无性丝状真菌有性分化及其发育的调控，证明了Asf1基因借助结合GTP结合蛋白参与MTOR信号转导途径、借助Dj-1家族蛋白参与细胞氧化应激反应途径，从而证明了Asf1参与了生物体的两条新的信号通路途径。本研究探明了无性丝状真菌有性发育遗传机制，为无性丝状真菌系统分类学做出了重要的理论贡献。