Synthetic microbial communities rescues strawberry from soil-borne disease by enhancing soil functional microbial abundance and multifunctionality

INTRODUCTION: Synthetic microbial communities (SynCom) contribute to mitigating soil-borne crop diseases while enhancing both crop quality and yield. However, relatively little research has been done on the intricate regulatory mechanisms of SynCom on the suppression of soil-borne diseases. OBJECTIVES: We aimed to elucidate the dynamic regulatory mechanisms and legacy effects of a SynCom on the composition of soil functional microorganisms, soil multifunctionality and crucial functions, and the suppression of soil-borne diseases. METHODS: We conducted an extensive series of experiments to assess the effect of a SynCom on the changes in the rhizosphere functional microorganisms and soil functions (e.g., multifunctionality, functionality of C, N, and P cycling) across six successive generations of strawberry in consecutive monoculture soils by employing amplicon metagenomics and transcriptome sequencing. RESULTS: Our results showed that the SynCom increased the aboveground fresh biomass of strawberry by 31-70.3% and the fruit biomass by 171.39-280.71%, and decreased the Fusarium oxysporum abundance by 17.91-49.51% compared to the consecutive monoculture. The SynCom significantly enhanced the soil C cycling and P cycling function, and soil multifunctionality (SMF). SynCom treatment significantly increased the Shannon diversity index and relative abundances of potentially beneficial bacteria and consumer protistan communities, while exerted a significant inhibitory effect on the Shannon diversity index and relative abundances of fungal pathogen. SEM result showed that SynCom significantly affected SMF by influencing soil nutrients, the abundance and diversity of functional microbial community. Our result also showed that the SynCom established the positive legacy effects on the abundance of rhizosphere soil beneficial bacteria, strawberry biomass and plant disease resistance-associated pathways (phenylpropanoid biosynthesis pathway, alpha-linolenic acid metabolism pathway), and negative effect on the abundance of pathogenic F. oxysporum under the 7th generation of strawberry cropping. CONCLUSION: Collectively, our study demonstrated the effectiveness of employing SynCom in mitigating soil-borne Fusarium oxysporum diseases by enhancing soil functional microbial abundance and soil multifunctionality.