Aira Manuel, Pérez-Losada Marcos, Crandall Keith A, Domínguez Jorge
Grupo de Ecoloxía Animal (GEA), Universidade de Vigo, 36310 Vigo, Spain.
Department of Biostatistics and Bioinformatics, Computational Biology Institute, Milken Institute School of Public Health, George Washington University, Washington, DC 20052, USA.
Microorganisms. 2022 May 13;10(5):1025. doi: 10.3390/microorganisms10051025.
Earthworms heavily modify the soil microbiome as it passes throughout their guts. However, there are no detailed studies describing changes in the composition, structure and diversity of soil microbiomes during gut transit and once they are released back to the soil as casts. To address this knowledge gap, we used 16S rRNA next-generation sequencing to characterize the microbiomes of soil, gut and casts from the earthworm . We also studied whether these three microbiomes are clearly distinct in composition or can be merged into metacommunities. A large proportion of bacteria was unique to each microbiome-soil (82%), gut (89%) and casts (75%), which indicates that the soil microbiome is greatly modified during gut transit. The three microbiomes also differed in alpha diversity, which peaked during gut transit and decreased in casts. Furthermore, gut transit also modified the structure of the soil microbiome, which clustered away from those of the earthworm gut and cast samples. However, this clustering pattern was not supported by metacommunity analysis, which indicated that soil and gut samples make up one metacommunity and cast samples another. These results have important implications for understanding the dynamics of soil microbial communities and nutrient cycles.
蚯蚓在其肠道中移动时会对土壤微生物群落产生重大影响。然而，目前尚无详细研究描述土壤微生物群落在肠道移动过程中以及作为蚓粪重新释放回土壤后其组成、结构和多样性的变化。为填补这一知识空白，我们使用16S rRNA下一代测序技术来表征蚯蚓的土壤、肠道和蚓粪的微生物群落。我们还研究了这三种微生物群落的组成是否明显不同，或者是否可以合并为一个元群落。每个微生物群落——土壤（82%）、肠道（89%）和蚓粪（75%）——都有很大一部分细菌是独特的，这表明土壤微生物群落在肠道移动过程中发生了很大变化。这三种微生物群落在α多样性上也存在差异，α多样性在肠道移动过程中达到峰值，在蚓粪中则下降。此外，肠道移动还改变了土壤微生物群落的结构，使其与蚯蚓肠道和蚓粪样本的结构聚类分离。然而，这种聚类模式并未得到元群落分析的支持，元群落分析表明土壤和肠道样本构成一个元群落，蚓粪样本构成另一个元群落。这些结果对于理解土壤微生物群落的动态和养分循环具有重要意义。
