基于全基因组系统发生的草菇基因家族显著扩增

Phylogenomic analysis reveals the significant expansion of gene families of Volvariella volvacea

【目的】从基因组层次研究草菇低温自溶异常代谢的分子特征。【方法】对21个真菌物种进行全基因组系统发生分析,进而选取其中具有代表性的物种进行比较基因组学分析,系统研究草菇异常代谢分子特征。【结果】全基因组系统发生分析结果显示草菇位于草腐菌所形成簇的底端。基于全基因组系统发生树,由于担子菌和子囊菌属于完全不同的演化路径,所以选取担子菌中具有代表性的9个物种进行比较基因组学分析,结果显示相比于其它草腐菌,草菇基因家族具有一定的收缩趋势。进一步对不同范畴的基因家族数目进行比较,结果显示3个大于200的草菇基因家族(fam1、fam4和fam6)分别发生了显著扩增,且在总数上也显著高于其它物种,表明草菇的这一分子特征与其异常代谢相关。【结论】3个草菇基因家族(>200)显著扩增提示其特定基因家族功能加强,很可能与草菇低温自溶密切相关。

[ Objective ] Cryogenic autolysis of Volvariella volvacea is an unusual phenomenon of abnormal metabolism. The aim of this study was to describe this molecular feature of abnormal metabolism at the genome-level. [Methods] We used 21 fungal species for the phylogenomic analysis and then selected 9 representative species in basidiomycetes for the comparative genomic analysis. [ Results] The phylogenomic analysis shows that V. volvacea was located at the bottom of the cluster consisting of grass-degrading fungi. Phylogenetic tree shows that basidiomycetes and ascomycetes fungi have independent evolutionary trajectories. Therefore, nine representative species in basidiomycetes were chosen for the comparative genomic analysis. The result shows that compared to other grass-degrading fungi, V. volvacea has the tendency of contraction. The comparison of the number of gene families on a different scale shows that there was a significant expansion of 3 large size （ 〉 200） gene families （faml, fam4 and fam6） in V. volvacea with their total number significantly more than other species, representing that the molecular feature of V. volvacea is correlated with its abnormal metabolism. [ Conclusion ~ The significant expansion of 3 gene families （ 〉 200 ） in V. volvacea indicates the enhancement of their function in specific gene families, which is most likely associated with cryogenic autolysis of V. volvacea.