Roots secrete many photosynthates into the rhizosphere and these exudates are important interfaces for host–microbiome interactions. The aerial roots of many wild plants and cereal crops, such as maize and sorghum, can secrete large amounts of mucilage which is a specific type of root exudates, but has been a neglected biological phenomenon.

A group of researchers from Xishuangbanna Tropical Botanical Garden (XTBG) recently investigated the interactions between root-zone microorganisms and plant root exudates. They proposed the aerial root mucilage probiotics system as a novel model for identifying the crucial interactions between functional metabolites and the probiotic microbiome.

Results of their study were published in The ISME Journal.

one Melastomataceae dicotyledon vine plant to identify the similarities and differences in metabolites and microbiome in the aerial root mucilage and underground rhizosphere.

They explored how root exudates affected the composition and function of root-zone microorganisms, and how these microorganisms in turn influenced plant health and growth. They also proposed how probiotics, including diazotrophic and functional microbiomes, were selected for use in the system.

They found that the root exudates significantly affected the growth and function of rhizosphere microorganisms, especially for strains in the probiotic model. Probiotics played an important role in maintaining the micro-ecological balance of the rhizosphere, providing a scientific basis for the development of new agricultural biotechnology strategies in the future.

The mucilage may contain functional attractor compounds and antimicrobials defence metabolites. Plants synthesized those functional compounds and secreted into the rhizosphere by root transporters. At the same time, the host used other element transporters to assimilate and absorb nutrients provided by rhizosphere functional microbiome.

“Multi-omics approaches (genomics, transcriptomics, metabolomics, and microbiomics) combined with molecular biology experiments can be used to analyze and verify the interactions between host mucus metabolites and the microbiome,” said PANG Zhiqiang, first author of the study.

They regarded that the aerial root mucilage–functional microbiome study system will provide new insights into the mechanisms by which root exudates maintain microbial function and stability in the rhizosphere microenvironment. Managing and optimizing the rhizosphere microbial community will possibly improve plant health and productivity.

The study was supported by the National Natural Science Foundation of China and the China Postdoctoral Science Foundation.

Contact

XU Peng Ph.D Principal Investigator

Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun 666303, Yunnan, China    

E-mail: xupeng@xtbg.ac.cn     

First published: 04 November 2024