宝天曼自然保护区甲虫肠道酵母菌多样性研究

Baotianman Nature Reserve, with abundant insect resources, is one of the major insect-producing areas in China. The gut of insects is a new hyperdiverse source of novel yeasts. However, it is still very limited to understand the diversity of yeasts in insect gut. Therefore, the beetle which is the most abundant species of insect groups in Baotianman Nature Reserve is chosen as the research project, we collect various insect samples of different species and ages from different places in Baotianman Nature Reserve, employ novel culturing strategies, isolate and preserve the yeast strains from the insect guts. Based on the morphology and microsatellite-primed PCR fingerprint analysis, the isolated strains from various sources were preliminary classified. Using rDNA-ITS combining molecular systematics, the phylogenetic realtionships of yeasts in the gut of insects and its closely related species were confirmed and the new taxa were systematically investigated. Novel yeast strains with excellent traits were obtained by screening their enzyme activity and determining their metabolic contents. This research will reveal the distribution and diversity of yeasts in digestive tract of insects, enrich the science knowledge on the interactions between yeasts in the gut of insects and their hosts and obtain yeast species resources with kinds of application values and rare characteristics. The results will provide science basis for studying molecular systematics of yeasts and the mechanism of the species evolution and for efficient utilization of yeast resources.

宝天曼国家自然保护区具有丰富的昆虫资源，是我国昆虫集中产区之一。昆虫肠道是酵母菌新种高度多样性的新来源，然而目前对昆虫肠道酵母菌多样性认识仍十分有限。本项目选择宝天曼国家自然保护区昆虫类群中种类最丰富的甲虫为研究对象,从该保护区不同地点大量采集不同种类或不同龄期的昆虫标本。采用新的培养策略，分离和保藏各种肠道酵母菌株。依据形态学特征和MSP-PCR指纹图谱分析，对大样本多来源分离菌株进行初步归类。使用rDNA-ITS相结合的分子系统学研究方法，确定其系统发育地位，发现并系统鉴定新的酵母菌类群。通过酶活性筛选和代谢产物含量测定，获得具优良性状的酵母菌新菌种。本项目将揭示酵母菌在甲虫肠道中的分布状况及多样性，丰富对昆虫肠道酵母菌与宿主之间相互关系的科学认识，获得具有各种应用价值和稀有特征的酵母菌资源。项目研究成果将为酵母菌分子系统学研究和物种演化机制的阐明及高效利用酵母菌资源提供科学依据。

昆虫肠道是酵母菌新种高度多样性的新来源，然而目前对昆虫肠道酵母菌多样性认识仍十分有限。本项目选择宝天曼国家自然保护区昆虫类群中种类最丰富的甲虫为研究对象, 采用新的分离培养策略研究宝天曼甲虫肠道酵母菌的多样性，研究成果体现在以下几个方面：（1）从甲虫肠道及相关环境中分离酵母菌735株，分属42个属142个不同的分类单元，其中Candida、Hyphopichia、Kluyveromyces、Lachancea、Pichia、Saccharomyces、Scheffersomyces和Torulaspora为优势类群，昆虫肠道酵母菌种类较多、丰度较高、多样性丰富。（2）发现10属30个新种，其中已发表新种23个，包括Starmerella anomalae、Scheffersomyces titanus、Wickerhamiella brachini、Nematodospora anomalae、Candida funiuensi、Candida baotianmanensis、Candida pseudoviswanathii、Pichia dushanensis 、Hyphopichia paragotoi、Spathaspora allomyrinae等，并对Spathaspora属的特征进行了修订，另有Blastobotrys 、Metschnikowia和Scheffersomyces等属新种7个，正在描述与准备过程中，以后将陆续发表。（3）研究中发现Starmerella、Scheffersomyces、Wickerhamiella 、Spathaspora 及Lodderomyces 分支等的一些种能从甲虫肠道持续分离，暗示这些酵母菌与昆虫有密切的关系，其生物学功能有待于进一步研究。在本项目的资助下，项目组成员已发表SCI论文13篇，申请国家发明专利3项，参加了7次国内学术会议，其中1次为大会特邀报告，培养研究生4名。