Comparative Analyses of Mitochondrial Genomes Provide Evolutionary Insights Into Nematode-Trapping Fungi
Comparative Analyses of Mitochondrial Genomes Provide Evolutionary Insights Into Nematode-Trapping Fungi
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线粒体基因组的比较分析为捕获线虫的真菌提供了进化见解
DOI：
10.3389/fmicb.2020.00617
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发表时间：
2020-04-15
影响因子：
5.2
通讯作者：
Xu，Jianping
中科院分区：
文献类型：
--
作者：
Zhang，Ying;Yang，Guangzhu;Xu，Jianping
Orbiliaceae(子囊菌门)中的捕食性真菌进化出了各种诱捕装置，使它们能够诱捕和杀死线虫、其他小动物和原生动物。这些诱捕装置包括粘附菌丝、粘附性旋钮、粘附网、紧缩环和非紧缩环。它们的多样性和实用价值引起了生物学家的极大关注，使它们成为研究适应性进化的优秀模式生物，并作为寄生线虫的生防剂。利用核蛋白编码基因研究了这些肉食性真菌之间可能的起源和进化关系，但它们的有丝分裂组关系和分歧模式仍不清楚。在这里，我们分析和比较了8个物种的12个真菌菌株的有丝分裂基因组，其中6个物种代表了所有四种线虫诱捕装置，2个来自相关但非捕食性真菌。所分析的12个有丝分裂体均为环状DNA分子，长度在146,101bp到280,699 bp之间。基因同时性分析表明，有丝分裂体间存在基因重排和内含子转移。此外，蛋白质编码基因(PCGs)的数量、GC含量、AT偏斜和GC偏斜在这些有丝分裂体间存在差异。内含子数目的增加和总大小的增加是造成有丝分裂体间长度差异的主要原因。蛋白质编码基因的系统发育分析表明，线粒体基因组和核基因组的进化速度不同，在参与能量代谢的几个基因中发现了正选择信号。我们的研究为捕食线虫真菌的进化提供了新的见解，并将促进对这类具有重要生态和农业意义的真菌的进一步研究。
Predatory fungi in Orbiliaceae (Ascomycota) have evolved a diversity of trapping devices that enable them to trap and kill nematodes, other small animals, and protozoans. These trapping devices include adhesive hyphae, adhesive knobs, adhesive networks, constricting rings, and non-constricting rings. Their diversity and practical importance have attracted significant attention from biologists, making them excellent model organisms for studying adaptative evolution and as biological control agents against parasitic nematodes. The putative origins and evolutionary relationships among these carnivorous fungi have been investigated using nuclear protein-encoding genes, but their patterns of mitogenome relationships and divergences remain unknown. Here we analyze and compare the mitogenomes of 12 fungal strains belonging to eight species, including six species representing all four types of nematode trapping devices and two from related but non-predatory fungi. All 12 analyzed mitogenomes were of circular DNA molecules, with lengths ranging from 146,101 bp to 280,699 bp. Gene synteny analysis revealed several gene rearrangements and intron transfers among the mitogenomes. In addition, the number of protein coding genes (PCGs), GC content, AT skew, and GC skew varied among these mitogenomes. The increased number and total size of introns were the main contributors to the length differences among the mitogenomes. Phylogenetic analyses of the protein-coding genes indicated that mitochondrial and nuclear genomes evolved at different rates, and signals of positive selection were found in several genes involved in energy metabolism. Our study provides novel insights into the evolution of nematode-trapping fungi and shall facilitate further investigations of this ecologically and agriculturally important group of fungi.