子囊菌交配型基因MAT1-1的系统发育

子囊菌具有无性态与有性态的复杂性,以及人们对其系统发育和亲缘关系了解的局限性,进而导致菌物学家对子囊菌分类尚持不同意见。子囊菌的交配型基因（MAT）进化保守,且编码的蛋白质调控子囊菌的有性生殖过程。核盘菌Sclerotinia sclerotiorum (Lib.) de Bary隶属于子囊菌门Ascomycota、盘菌纲Discomycete,是一种典型丝状同宗配合真菌,控制该菌有性生殖的交配型基因MAT1-1和MAT1-2紧密连锁,且该菌并无有性态与无性态的复杂性。故此,本文根据所克隆的核盘菌交配型基因MAT1-1,利用PAUP*软件将82种含有Alpha-box交配型基因的子囊菌进行了系统进化分析,通过核苷酸及氨基酸水平的系统发育分析,并结合Ainsworth（1973）分类系统及最新的Deep Hyphae（2006）分类系统的对比研究,发现所构建的系统进化树与传统分类所表现的进化关系基本一致,且核盘菌交配型基因MAT1-1在进化过程中功能相对保守,该分析结果有助于对其他子囊菌交配型基因的克隆、系统分类与进化研究,同时对核盘菌的亲缘关系、病害预测及防治等具有重要意义。

Phylogenetics of the mating type gene MAT1-1 in ascomycetes

Due to obscure knowledge to ascomycete phylogenetics, genetic relationship, and its complexity of anamorph and teleomorph, mycologists still hold different opinions on the ascomycete classification. The anagenesis of mating type (MAT) gene is conservative, and the protein coded regulates the sexual reproductive process of ascomycetes. Sclerotinia sclerotiorum is a typical filamentous homothallic fungus which belongs to Ascomycota, Discomycetes. The mating type genes MAT1-1 and MAT1-2, which regulate fungal sexual reproduction, are closed linked to each other at the same chromosome and the fungi do not maintain complexity of anamorph and teleomorph. Therefore, based on the cloned S. sclerotiorum mating type gene MAT1-1, this study generated a phylogenic analysis by PAUP* with other 81 mating type genes containing Alpha-box domain from fungi. Through phylogenic analysis on the level of nucleotide and amino acid and comparative study under Ainsworth’s classification system and the latest classification system of Deep Hyphae, it is found that the evolutionary phylogenic tree constructed illustrates basically the same evolutionary relationship in traditional classification, and the function of mating type gene MAT1-1 is relatively conservative in the evolutionary process. The result is helpful to the study of cloning, phylogenetic classification and anagenesis of other mating type genes in ascomycetes. Moreover, it has great significance on the phylogeny, disease prediction and prevention of S. sclerotiorum.