白头鹤肠道微生物菌群复合体时空动态及其环境响应机制

Gut microbiota have numerous and complex relationships with their hosts, and have been found to provide many beneficial functions such as aiding in the digestion of otherwise indigestible substances, developing and stimulating the immune system, play a critical role in functions that sustain health and is so-called ‘metaorganism’. The internal and external environmental factors that affect on the structure and function of intestinal microbiota are becoming the current hot topics in the study of zoology. Migratory waterbirds are good model animals for gut microbiology which are sensitive to environmental change as a result of their use of geographically widespread habitats throughout their annual cycle and often suggested as vectors of infectious diseases due to their potential for spreading pathogens over large geographical distances. The local environment thus has the potential to alter avian gut microbiota. This research will investigate gut microbiota diversity and function including determinants of the environmental factors such as geographic differences, feeding habits and seasonal change, poultry and livestock, sympatric wintering geese and internal factors such as gender, host genetic distance and parasite infection on the gut microbiota by the hooded crane fecal with the help of 16s/ITS/SSU rRNA high-throughput sequencing technology and microbial metagenomic analysis to clarify the mechanism of gut microbiota responding to environmental factors. Through the metabolic pathway of gut microbiota metagenomic analysis, combined with the diet analysis results, to clarify the response mechanism of gut microbiota on the feeding of generalization and specialization. Though the similarity comparison of the diversity between hooded crane and animal pathogenic bacteria, to evaluate of the disease original and disease risk. This project is to further enrich the gut microbiology and ecology research of migratory waterbirds, has a positive significance to carry out the endangered species protection.

动物及其肠道微生物互交作用形成动物-微生物复合体，肠道菌群参与动物消化和免疫等重要生命活动过程，维持动物的健康，寄主内部和外界环境因素对肠道菌群结构和功能的影响成为当前动物学研究的热点。迁徙水鸟周年生活中面临复杂多样的环境选择压力，同时具有较高的病原菌传播风险，因此其肠道微生物倍受关注。本项目借助16s/IST/SSU rRNA高通量测序技术，通过粪便微生物宏基因组分析，研究白头鹤越冬和迁徙种群肠道菌群特征，探讨地理差异、食性变化、季节变化、家禽和家畜、同域越冬雁类等环境因素，以及性别和寄生虫感染等内在因素对肠道菌群结构的影响，阐明肠道菌群对寄主内外环境的响应机制；通过肠道微宏基因组代谢通路分析，结合食性分析，阐明肠道微生物对食性泛化与特化的响应机制；通过白头鹤与畜禽病原菌群相似程度的识别，评估疫原疫病风险。本项目对于进一步丰富迁徙水鸟肠道微生物学和生态学研究和开展濒危物种种群保护具有积意义。

动物肠道微生物对寄主生命活动具有重要意义，其结构和功能受寄主体外环境因素的影响。迁徙水鸟周年生活中面临复杂多样的环境选择压力，同时具有较高的病原菌传播风险。本项目借助16srRNA高变区的高通量测序技术，通过粪便微生物宏基因组分析，研究白头鹤(Grus monacha)越冬种群肠道菌群特征及其与环境因素的关系。结果表明，越冬白头鹤肠道微生物优势菌群主要由厚壁菌门（Firmicutes）、变形菌门（Proteobacteria）、拟杆菌门(Bacteroidetes) 和放线菌门(Actinobacteria) 组成。越冬白头鹤与同域家养灰雁肠道菌群共29个门、364个科、690个属，各分类阶元及其丰度在两宿主肠道中表现不同程度的差异；越冬期家养灰雁共有的肠道细菌门占82.1%；整个越冬期，二者共检测出34个潜在肠道致病菌，其中13种为共有致病菌。白头鹤和豆雁肠道细菌OTU的数量随着越冬期而增加，越冬中期和后期共有OTU以及菌群结构相似性均大于越冬前期和中期；越冬期白头鹤比豆雁具有更加丰富的肠道细菌群落多样性，寄主种内肠道菌群结构大于种间的相似度；随着白头鹤和豆雁接触时间增加，两个寄主共有细菌类型增加，生态位重叠增加了细菌在两个宿主之间传播的可能性。越冬期白头鹤和家鸭的核心菌门较为相似且稳定；白头鹤与附近不同距离的家鸭肠道菌群结构都存在显著差异；随着越冬期延伸，白头鹤与家鸭肠道细菌交叉感染程度增加；潜在致病菌的重叠度也逐步增强。保护等级相似的白头鹤栖息地，面积小的升金湖白头鹤肠道细菌和真菌群落的Alpha多样性均显著高于面积大的鄱阳湖，鄱阳湖、菜子湖和升金湖白头鹤肠道细菌和真菌群落结构上均存在显著分化，肠道菌群表现生境差异，宿主生境是塑造肠道菌群结构的重要因素，单位面积内更多的水鸟之间的交互作用也是重要因素。鸟类食物的变化对肠道菌群变化产生影响，升金湖越冬的白头鹤主要食物稻谷、蓼子草和陌上菅均与肠道细菌和潜在致病菌群落组成显著相关。本项目研究结果进一步丰富迁徙水鸟肠道微生物和生态学研究的内容，以于开展濒危物种的种群保护具有积意义。