Background and aims

Root-associated microbiome, especially the core taxa, profoundly affect host fitness. Previous studies have shown that the fungal probiotic Phomopsis liquidambaris caused the reassembly of the peanut root core microbiome, promoting plant growth and disease resistance. However, the assembly mechanism of the root core microbiome remains largely unknown.

Methods

The rhizosphere bacterial communities and the dynamic changes of core microbes were analyzed throughout the growing season with high-throughput sequencing. High-Performance Liquid Chromatography was carried out to determine the influence of Ph. liquidambaris colonization on the metabolic profiles of peanut root exudates. Based on correlation analysis, bacterial growth, biofilm formation, and chemotaxis experiments were carried out to verify the effect of Ph. liquidambaris-induced root exudates on colonization behavior of core microbes. The nested plate assay was used to analyze the interaction between fungal networks and core microbes.

Results

Here, we demonstrated that the process from bulk soil to rhizosphere is a key step in the peanut root microbiome reassembly. In vitro and in vivo experiments revealed that Ph. liquidambaris-induced changes in root exudates mediated the reassembly process by promoting the colonization of Bacillus sp. HB1, Streptomyces sp. MB6, and Bradyrhizobium sp. MB15. Further, we found that the Ph. liquidambaris hyphal network selectively promotes bacterial dispersal and collaborates with root exudates to encourage the enrichment of core microbes.

Conclusion

Our results revealed that the additive effect of plant chemistry and physical network supports the fungal probiotics caused peanut root microbiome reassembly, mediating plant fitness to monocropping obstacles.

中文翻译：

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真菌网络和植物代谢物驱动花生根微生物组的组装

 背景和目标

根相关微生物组，尤其是核心类群，会深刻影响宿主的适应性。既往研究表明，真菌益生菌 Phomopsis liquidambaris 引起花生根核心微生物组的重组，促进植物生长和抗病性。然而，根核心微生物组的组装机制在很大程度上仍然未知。

 方法

通过高通量测序分析整个生长季的根际细菌群落和核心微生物的动态变化。进行高效液相色谱法以确定液苯疟定植对花生根系分泌物代谢谱的影响。基于相关性分析，进行细菌生长、生物被膜形成和趋化性实验，以验证 Ph. liquidambaris 诱导的根系分泌物对核心微生物定植行为的影响。巢板测定法用于分析真菌网络与核心微生物之间的相互作用。

 结果

在这里，我们证明了从大块土壤到根际的过程是花生根微生物组重组的关键步骤。体外和体内实验表明，液态霉菌诱导的根系分泌物变化通过促进芽孢杆菌 HB1、链霉菌 MB6 和缓根瘤菌 MB15 的定植来介导重组过程。此外，我们发现液态乳杆菌菌丝网络选择性地促进细菌扩散并与根系分泌物合作以促进核心微生物的富集。

 结论

我们的结果表明，植物化学和物理网络的加性效应支持真菌益生菌导致花生根微生物组重组，介导植物对单一作物障碍的适应性。