Mechanism of synthetic communities in improving acidic soil and promoting crop growth

This is the authors' abstract. We don't add key points for this paper.

Native core microbiomes represent a unique opportunity to support soil health and enhance plant quality. However, these microbiomes are often neglected in the development of synthetic communities (SynComs) aimed at improving agricultural ecology. Herein, by low-carbon enrichment, combination, and functional analysis, two strains of Paracoccus communis capable of improving soil acidity and promoting crop growth were identified and utilized to construct a SynCom. A microbial agent was prepared using filter mud as a carrier, and its ameliorative effect on acidic soil was investigated. The SynComs exhibited significant in vitro secretion of alkali and indole-3-acetic acid (IAA), with pH and indole acid production values recorded at 8.3 and 35.53 mg/L, respectively. Pot experiments demonstrated that SynComs effectively colonized the rhizosphere, resulting in a rhizosphere soil pH increase from 4.73 to 5.50. Application of the microbial agent led to a substantial enrichment of C-related genes, with the cbbL gene increasing by 25-fold, alongside enhanced dehydrogenase activity. Genes associated with ammonium N production and P solubilization were activated. Furthermore, key microbial species that drive C, N, and P dynamics were significantly enriched. Genes involved in rhizosphere-regulated production of indole-3-acetic acid were notably upregulated. The fixation of carbon and nitrogen, solubilization of P, and production of IAA collectively promoted plant growth, alleviating the stress of acidic soil on plants. These findings underscore the potential of microbial tools for advancing sustainable agriculture in acidic and infertile soils.