Sustained Inhibition of Maize Seed‐Borne Fusarium Using a Bacillus‐Dominated Rhizospheric Stable Core Microbiota with Unique Cooperative Patterns

Abstract

Seed-borne pathogens can inhabit the rhizosphere and infect the plant after germination. The rhizosphere microbiome plays critical roles in defending against seed-borne pathogens. However, the assembly of a core rhizosphere microbiome to suppress seed-borne pathogens is unknown. Here, the root-associated microbiome is infested with seed-borne Fusarium in sterile environment, while the root-associated microbiome is not infested when it interacts with the native soil microbiome across maize cultivars, suggesting that a core rhizosphere microbiome assembles to suppress seed-borne Fusarium. Two strategies of progressive dilution and rhizodepositional attraction are applied to identify the core rhizobacteria. A synthetic microbiota (SynM) is constructed using the isolates of the core rhizobacteria and optimized according to superior community stability and Fusarium-suppression capability, which surpasses the single strain and randomly formed microbiota. The optimized SynM (OptSynM) presents a distinctive cooperative pattern in which a key strain harbors the Fusarium suppression function by synthesizing the antagonistic substance fengycin, while other members intensify the functional performance by promoting the growth and the expression of the antagonistic and plant-growth-promoting related genes of the key strain. This study demonstrates innovative approaches to construct stable and minimal microbiota for sustainable agriculture and proposes a unique cooperative pattern to sustain community stability and functionality.

Biocontrol mechanisms of Bacillus: Improving the efficiency of green agriculture

“…The top‐down strategy refers to the gradual selection of key microbial agents from environmental samples based on physiological and functional screening (Lawson et al, 2019 ). Xun et al ( 2023 ) used two strategies, progressive dilution and rhizodepositional attraction, to identify the core rhizobacteria taxa responsible for the suppression of maize seed‐borne Fusarium . Consequently, a bacterial consortium was constructed using these keystone strains and optimized according to superior community stability and disease suppression capability, resulting in a simplified SynCom composed of eight strains from the genus of Bacillus , Burkholderia , Enterobacter , Lysobacter , Stenotrophomonas , Pseudoxanthomonas , Pseudomonas , and Acinetobacter .…”

A Synthetic Microbial Community of Plant Core Microbiome Can Be a Potential Biocontrol Tool

“…One or several key strains in SynComs are dominant, and the other strains help the plant produce stress resistance to pathogenic bacteria by assisting key bacterial communities. 113 The inoculants may use metabolites to defend those friendly to their functions and attack those who do not support the growth of microorganisms with similar functions to form SynComs to promote plant immunity to diseases. 114 The effect of a single strain in SynComs on plants is not apparent, but the synergistic effect of several strains forming the SynComs has a more significant impact on the resistance of plants to pathogens.…”

“…There are various ways to promote plant growth in stable SynComs. One or several key strains in SynComs are dominant, and the other strains help the plant produce stress resistance to pathogenic bacteria by assisting key bacterial communities . The inoculants may use metabolites to defend those friendly to their functions and attack those who do not support the growth of microorganisms with similar functions to form SynComs to promote plant immunity to diseases .…”

Can we control potato fungal and bacterial diseases? — microbial regulation

“…Currently, attempts have been made to introduce synthetic communities (SynCom) that include multiple microbial strains into sterile or non inhibitory soils [ 91 ]. The key to synthesizing a community is to optimize its ability to inhibit pathogens using core microorganisms, which have an inhibitory effect that exceeds that of single strains and randomly formed microbial communities [ 92 ]. Studies have found that the optimized synthetic community exhibits a unique cooperative pattern, including key strains that have inhibitory effects on pathogenic microorganisms through the synthesis of antagonistic substances, while other members enhance their function by promoting the growth of key strains and plant growth [ 93 ].…”