Laboratory for Conservation and Utilization of Bio-Resources, and Key Laboratory of Microbial Diversity in Southwest China, Ministry of Education, Yunnan University, Kunming, P. R. China.
PLoS Pathog. 2011 Sep;7(9):e1002179. doi: 10.1371/journal.ppat.1002179. Epub 2011 Sep 1.
Nematode-trapping fungi are "carnivorous" and attack their hosts using specialized trapping devices. The morphological development of these traps is the key indicator of their switch from saprophytic to predacious lifestyles. Here, the genome of the nematode-trapping fungus Arthrobotrys oligospora Fres. (ATCC24927) was reported. The genome contains 40.07 Mb assembled sequence with 11,479 predicted genes. Comparative analysis showed that A. oligospora shared many more genes with pathogenic fungi than with non-pathogenic fungi. Specifically, compared to several sequenced ascomycete fungi, the A. oligospora genome has a larger number of pathogenicity-related genes in the subtilisin, cellulase, cellobiohydrolase, and pectinesterase gene families. Searching against the pathogen-host interaction gene database identified 398 homologous genes involved in pathogenicity in other fungi. The analysis of repetitive sequences provided evidence for repeat-induced point mutations in A. oligospora. Proteomic and quantitative PCR (qPCR) analyses revealed that 90 genes were significantly up-regulated at the early stage of trap-formation by nematode extracts and most of these genes were involved in translation, amino acid metabolism, carbohydrate metabolism, cell wall and membrane biogenesis. Based on the combined genomic, proteomic and qPCR data, a model for the formation of nematode trapping device in this fungus was proposed. In this model, multiple fungal signal transduction pathways are activated by its nematode prey to further regulate downstream genes associated with diverse cellular processes such as energy metabolism, biosynthesis of the cell wall and adhesive proteins, cell division, glycerol accumulation and peroxisome biogenesis. This study will facilitate the identification of pathogenicity-related genes and provide a broad foundation for understanding the molecular and evolutionary mechanisms underlying fungi-nematodes interactions.
线虫诱捕真菌是“肉食性的”，它们使用专门的诱捕装置来攻击宿主。这些诱捕器的形态发育是它们从腐生到捕食生活方式转变的关键指标。本文报道了线虫诱捕真菌节丛孢菌（Arthrobotrys oligospora Fres.）（ATCC24927）的基因组。该基因组包含 40.07 Mb 组装序列，预测有 11479 个基因。比较分析表明，与非致病性真菌相比，A. oligospora 与致病性真菌共享更多的基因。具体来说，与几个已测序的子囊菌真菌相比，A. oligospora 基因组在枯草杆菌蛋白酶、纤维素酶、纤维二糖水解酶和果胶酯酶基因家族中具有更多与致病性相关的基因。在病原体-宿主相互作用基因数据库中搜索发现了 398 个与其他真菌致病性相关的同源基因。重复序列分析为 A. oligospora 中的重复诱导点突变提供了证据。蛋白质组学和定量 PCR（qPCR）分析显示，90 个基因在线虫提取物诱导的诱捕器形成早期阶段显著上调，这些基因大多数参与翻译、氨基酸代谢、碳水化合物代谢、细胞壁和膜生物发生。基于综合基因组、蛋白质组和 qPCR 数据，提出了该真菌线虫诱捕装置形成的模型。在该模型中，其线虫猎物激活了多个真菌信号转导途径，进一步调节与各种细胞过程相关的下游基因，如能量代谢、细胞壁和粘蛋白生物合成、细胞分裂、甘油积累和过氧化物酶体生物发生。这项研究将有助于鉴定与致病性相关的基因，并为理解真菌-线虫相互作用的分子和进化机制提供广泛的基础。
