土壤细菌网络互作调控线虫肠道细菌群落

Nematode gut bacterial communities are regulated by soil bacterial network interactions

摘要:

动物肠道细菌群落在联系宿主与生态系统功能中发挥着至关重要的作用。【目的】本研究旨在评估绿肥翻压和水稻生长不同时期对土壤细菌和线虫肠道细菌群落组成和结构的影响，并探究土壤细菌和线虫肠道细菌群落间的潜在关联关系。【方法】基于盆栽试验，结合16S rRNA基因高通量测序技术，分析黑麦草翻压和对照处理下水稻生长的前期(返青期)和后期(收获期)土壤细菌和线虫肠道细菌群落，结合网络分析研究土壤细菌网络互作对线虫肠道细菌群落的潜在影响。【结果】黑麦草翻压对土壤细菌和线虫肠道细菌群落组成和结构没有显著影响(P>0.05)；水稻生长后期样品比前期样品具有更高的α多样性。基于随机森林机器学习法获得的土壤细菌和线虫肠道细菌生物标志物之间存在广泛的显著相关关系，为土壤细菌群落变化调控线虫肠道细菌群落组成提供了有力的证据。共现网络分析表明土壤细菌之间的正相互作用显著促进了土壤细菌和线虫肠道细菌之间的正相互作用(P<0.01)，进而影响了线虫肠道细菌之间的网络互作。结构方程模型进一步表明土壤养分含量的降低主要通过降低土壤细菌之间正相互作用，从而间接影响线虫肠道细菌之间的互作。【结论】土壤细菌互作可能在调控线虫肠道细菌互作和群落组成方面有重要作用。

Abstract:

The gut microbiota of animals plays a crucial role in bridging host and ecosystem functions. [Objective] We aimed at assessing the effects of ryegrass application and different sampling periods of rice growth stages on the composition and structure of soil bacterial and nematode gut bacterial communities and exploring their potential linkages. [Methods] Based on a pot experiment, soil bacterial and nematode gut bacterial communities in the early (green returning period) and later (harvest period) stages of rice growth under ryegrass application and control treatments were analyzed by using 16S rRNA gene high-throughput sequencing technology. The potential impact of soil bacterial interactions on nematode gut bacterial communities was further studied with the network analysis. [Results] Ryegrass application did not significantly affect the composition and structure of soil and nematode gut bacterial communities (P>0.05). The later samples had higher alpha diversity than earlier ones. Extensive and significant correlations between soil bacterial and nematode gut bacterial biomarkers were obtained based on random forest machine learning, providing strong evidence that soil bacterial community changes regulate intestinal bacterial community composition of nematodes. Co-occurrence network-based analysis showed that positive interactions among soil bacteria were significantly (P<0.01) positively correlated with positive interactions between soil and nematode gut bacteria, thereby influencing network interactions among nematode gut bacteria. Structural equation modeling (SEM) further showed that the reduction of soil nutrients indirectly affected the network interactions among nematode gut bacteria mainly by reducing the positive network interactions among soil bacteria. [Conclusion] Soil bacterial interactions may play important roles in regulating network interactions and community composition of nematode gut bacteria.