中国林蛙蝌蚪肠道及皮肤微生物多样性分析

Analysis of Skin and Gut Microbiota in the Rana chensinensis Tadpoles

肠道及皮肤微生物群落对宿主的健康有着至关重要的影响。本研究使用16S rRNA基因测序技术研究中国林蛙(Rana chensinensis)Gosner38期蝌蚪肠道和皮肤共生微生物群落组成之间的差异。在门水平上,林蛙蝌蚪肠道中的优势门为变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidetes),皮肤中的优势门为拟杆菌门、变形菌门和疣微菌门(Verrucomicrobia)。此外,显著性检验结果显示,肠道中厚壁菌门和放线菌门(Actinobacteria)的丰度显著偏高,皮肤中拟杆菌门的丰度显著偏高。肠道微生物群落多样性高于皮肤,而肠道和皮肤的物种丰富度之间无显著差异。在对KEGG通路的丰度进行比较时,结果显示肠道"环境信息处理"功能的丰度显著高于皮肤,而皮肤中"遗传信息处理"及"新陈代谢"功能显著偏高。本研究提示林蛙蝌蚪肠道及皮肤微生物群落组成之间存在显著差异。

The gut and skin play important roles in the body’s immune system and are often exposed to the external environment. The difference in microbial communities can reflect the changes of the host in response to different environmental conditions. Whilenumerous gut and skin microbia have been characterized, there is no comparative analysis of the gut and skin microbial communities in the amphibian. In our study, we examined the difference of gut and skin tissues of Rana chensinensis tadpoles by hematoxylin-eosin(H.E) and Masson staining. Furthermore, we investigated the difference of gut and skin microbial communities in R. chensinensis tadpoles at Gosner stage 38 by using high-throughput 16 S rRNA sequencing technology. The statistical significance of difference was determined by the Student’s T-test. Our results revealed that:(1) There were histological structure difference of gut and ventral skin in tadpoles(Fig. 1).(2) The alpha diversity analysis showed that the microbial community biodiversity in the gut was significantly higher than that in the skin(P ≤ 0.001), while there was no difference in community richness between gut and skin samples(P > 0.05;Fig. 3). In addition, the hierarchical cluster and PCoA analysis showed that the distance of microbial communities between these two tissues was clearly separated from one another(Fig. 4).(3) Venn diagram showed that 175 OTUs were shared bythe gut and skin, while 70 OTUs were independently presented in the gut, and 87 in the skin(Fig. 5).(4) A taxonomic analysis revealed that the most prevalent phyla in the gut were Bacteroidetes, Proteobacteria and Verrucomicrobia, whereas the predominant phyla found in skin were Proteobacteria, Firmicutes and Bacteroidetes(Fig. 6 a). Moreover, the Student’s T-test results revealed that the abundance of Firmicutes and Actinobacteria in the gut was significantly higher than in the skin, while the abundance of Bacteroidetes was just significantly higher in the skin(P ≤ 0.05;Fig. 6 b).(5) The functional prediction results indicated that the abundance of "environmental information processing" function was significantly higher in the gut, whereas the "genetic information processing" and "metabolism" functions were significantly higher in the skin(P ≤ 0.01;Fig. 9). The results of this study revealed that there were significant differences in the composition of microbial communities in the gut and skin of R. chensinensis tadpoles. These differences will promote the growth and development of tadpoles to adapt to environmental changes.