西藏接合菌物种多样性初探

Species diversity of zygomycotan fungi in the Tibet Autonomous Region

摘要:

【背景】接合菌在自然界广泛分布，在工业、食品、医药、生物防治等方面扮演着重要的角色，部分接合菌为有害菌。西藏地区接合菌只有少数零星的报道，其系统调查研究几乎还是空白，大量潜在的物种需要分离、鉴定、认识、保藏和开发。【目的】了解西藏地区的接合菌物种多样性和生物资源现状，为该地区有害接合菌的控制和有益接合菌的开发利用奠定基础。【方法】对西藏全境7个地区19个代表县的701个样品采用平板稀释分离法得到单菌落，然后进行形态和分子(SSU、ITS和LSU rDNA)鉴定，并在此基础上进行生物多样性以及优势和稀有属种分析。【结果】得到西藏接合菌10属26种，包括5个西藏已知种和21个西藏新记录种；其中4个为中国新记录种，分别是：类变形被孢霉(Mortierella amoeboidea)、球孢高山被孢霉(M. globalpina)、灰褐毛霉(Mucor brunneogriseus)、暗色毛霉(M. fuscus)。西藏接合菌的多样性指数分析表明，不同地区间的物种数量和组成存在显著差异，排在前4位的分别是波密县、米林县、当雄县和八宿县。属种分析显示，西藏接合菌的2个优势属为被孢霉属(Mortierella)和毛霉属(Mucor)；3个优势种为高山被孢霉(Mortierella alpina)、冻土毛霉(Mucor hiemalis)、匍枝根霉(Rhizopus stolonifer)；常见属8个，分别是犁头霉属(Absidia)、放射毛霉属(Actinomucor)、小克银汉霉属(Cunninghamella)、根毛霉属(Rhizomucor)、根霉属(Rhizopus)、共头霉属(Syncephalastrum)、伞形霉属(Umbelopsis)和接霉属(Zygorhynchus)；常见种9个，稀有种14个。【结论】西藏地区接合菌资源丰富，各地区生物多样性差异显著，稀有物种占一半以上的比例提示西藏自然环境保护的重要性。

Abstract:

[Background] Zygomycotan fungi are widely distributed in nature. While some members are harmful, more zygomycotan fungi play an important role in industry, food, medicine, biological control, and so on. They have just been reported sporadically in the Tibet and lack a systematic survey. A large number of potential species need to be isolated, identified, understood, preserved and exploited. [Objective] To understand the species diversity of zygomycotan fungi in the Tibet, and lay a foundation for the control of harmful zygomycotan fungi and the utilization of beneficial ones in this area. [Methods] Zygomycotan fungi isolated with plate dilute method from 701 samples in 19 representative counties all over the seven prefectures of Tibet, were identified morphologically and molecularly, with SSU, ITS and LSU rDNA as markers. Based on these data, the biodiversity, dominant and rare taxa of Tibetan zygomycotan fungi were analyzed. [Results] Tibetan zygomycotan fungi obtained here were classified into 10 genera and 26 species. Among these species, five have been reported in the Tibet, while 21 species are new to Tibet; Four species are even new to China, which are Mortierella amoeboidea, M. globalpina, Mucor brunneogriseus and M. fuscus. The diversity index analysis of Tibetan zygomycotan fungi showed significant differences in the number and composition of species among regions. The most diverse four counties are Bome, Mainling, Dangxung and Baxoi. Analyses of species and genera revealed two dominant zygomycotan genera in the Tibet, Mortierella and Mucor, as well as three dominant species Mortierella alpina, Mucor hiemalis, and Rhizopus stolonifer. Eight common genera are Absidia, Actinomucor, Cunninghamella, Rhizomucor, Rhizopus, Syncephalastrum, Umbelopsis and Zygorhynchus. Common and rare species are 9 and 14, respectively. [Conclusion] The zygomycotan fungi in the Tibet are rich and significantly different in biodiversity among regions. Rare species account for more than half, implying the importance of protecting the natural environment of Tibet.