黏菌个体发育与黏菌内细菌关系的研究

Myxomycetes are a kind of eukaryote which have the characters of both protozoan and fungus. They hold a special status in organic evolution. Since their classificatory station is always in dispute, the study of myxomycetes' phylogeny are always concerned by researchers. Resently, the research in this area is specific to myxomycetes themselves, which does not involve myxomycetes in the natural link with other organisms in the ecosystem. Bacteria is not only an important food source for Myxomycetes, but also exists in plasmodium and sporophore of myxomycetes likely to provide favorable conditions for the survival of myxomycetes. However, relationships between endo-plasmodium bacteria and myxomycetes have not given reports. In our group, we already had certain study myxomycetes on the basis of ontogeny and phylogeny. The relationship between myxomycetes and bacteria is analyzed by comparing ribosomal genes based on 454 sequencing and morphological characteristics. Laboratory culture and fluorescence labeling of typical myxomycetes are used in observation of the microstructure characteristics of ontogeny. Comparison of the Myxomycetes' characteristics between endo-plasmodium bacteria and non-bacteria in the satge of Myxomycetes ontogeny. It analyses the structure of endo-plasmodium bacteria and endophytic bacteria influences on myxomycetes ontogeny. The effect of endo-plasmodium bacteria to myxomycetes' ontogeny will be expounded. It will be discussed that the phylogenic relationships between myxomycetes and endo-plasmodium bacterial. In addition, it provides theoretical basis for the study of the evolution of the Myxomycetes locations.

黏菌是一类兼具原生动物和菌物特征的真核生物，在进化中处于特殊地位，其分类归属一直存在争议，使得黏菌的系统发育被研究者所关注。目前该方面研究多是涉及黏菌本身的研究，并未涉及黏菌在自然生态系统中与其它生物的联系。细菌不仅是黏菌的重要食物来源，并且有些存在于黏菌原生质团和子实体中，可能为黏菌的生存提供有利条件。然而，黏菌个体发育及系统发育与黏菌内细菌关系的研究并无报告。本课题拟在课题组已有的黏菌个体发育和系统发育研究基础上，利用454测序，结合表观特征，比对黏菌及黏菌内细菌的核糖体基因，分析不同生境下黏菌对细菌的选择关系；对黏菌代表种进行实验室培养及荧光标记，比较黏菌个体发育主要阶段含有内细菌与无菌时的黏菌形态差异，分析黏菌内细菌种群结构及其对黏菌个体发育的影响。以期阐明黏菌内细菌在黏菌个体发育中的作用，探讨黏菌代表类群与黏菌内细菌的分子系统学关系，为黏菌的进化研究提供理论依据。

黏菌是一类兼具原生动物和菌物特征的真核生物，在进化中处于特殊地位，其分类归属一直存在争议，使得黏菌的系统发育被研究者所关注。细菌不仅是黏菌的重要食物来源，并且有些存在于黏菌原生质团和子实体中，可能为黏菌的生存提供有利条件。本项目明确黏菌内细菌的多样性：采用16S扩增子测序方法完成了6目9科33属的112份黏菌子实体与原生质团的黏菌内细菌多样性测序，共获得OTUs 7077个，其中注释到种OTUs 1127个；分析了黏菌及其内细菌在目、科、属、种级分类单元上的差异与关联。阐明黏菌内细菌对黏菌在个体发育过程中的影响：采用冷冻切片与荧光标记方法，明确了黏菌内细菌在黏菌不同发育阶段的分布位置；对黏菌个体发育不同阶段样品进行16S扩增子测序，分析了黏菌内细菌的种群多样性变化；选取不同营养条件下的原生质团进行转录组测序，初步阐释了黏菌内细菌的功能作用。揭示了黏菌与其内细菌的系统关系：对黏菌及其内细菌多样性进行聚类分析，明确了黏菌内细菌主要种群的关联；对黏菌各属内的共有细菌进行系统发育分析，对比黏菌系统发育关系，探讨部分黏菌内细菌与黏菌的潜在系统关系。综合以上研究，黏菌内细菌在黏菌个体发育与系统发育上都体现了密切关系，研究黏菌及其内细菌的关系研究，可为诠释黏菌的营养、 分布、 遗传及演化等方面提供重要科学依据 。