Microbiome of the terrestrial brachyuran crab Chiromantes haematocheir

The transition to terrestrial environments has occurred repeatedly and at different geological times in arthropods, but almost no information is available about the role of symbiotic microbiota in such process. Here we investigated the associated microbiota of a terrestrial brachyuran crab, Chiromantes haematocheir, using a targeted metagenomic approach. Bacterial 16S rRNA gene and fungal ITS sequences were obtained from selected crab organs and environmental matrices to profile microbial communities. We found stable and organ-specific communities of microorganisms associated to the gut and the gills of the crabs, the former involved in the digestion of vascular plant tissues. These communities were mainly composed by prokaryotic organisms and significantly differed from the fungi-dominated ones present in the environment. Our results suggest that the establishment of a specific, stable -microbiota may be crucial to drive evolutionary transitions, as colonization of terrestrial environments.

节肢动物向陆地生境的演化跃迁在地质历史中多次独立发生，且发生于不同的地质时期，但目前几乎尚无关于共生微生物群在该类演化过程中发挥作用的相关研究资料。本研究针对陆生短尾类蟹类厚纹蟹（Chiromantes haematocheir）的共生微生物群展开探究，采用靶向宏基因组学分析方法。我们从选定的蟹类器官及环境基质中获取细菌16S rRNA基因与真菌ITS序列，以此解析微生物群落的组成特征。研究发现，蟹类肠道与鳃部存在稳定且具有器官特异性的微生物群落，其中肠道微生物群参与维管植物组织的消化过程。这些群落主要由原核生物构成，且与环境中以真菌为主导的微生物群落存在显著差异。本研究结果表明，建立特定且稳定的微生物群，或许如同陆地生境定植过程一样，是驱动演化跃迁的关键因素。