Endophytic Fungus Reshapes Spikelet Microbiome to Reduce Mycotoxin Produced by Fusarium proliferatum through Altering Rice Metabolites

Rice spikelet rot disease (RSRD) caused by Fusarium proliferatum seriously reduces rice yield and produces mycotoxins that threaten human health. The root symbiotic endophytic fungus Phomopsis liquidambaris reduces RSRD incidence and fumonisins accumulation in grain by 21.5 and 9.3%, respectively, while the mechanism of disease resistance remains largely elusive. Here, we found that B3 significantly reduced the abundance of pathogen from 79.91 to 2.84% and considerably enriched resistant microbes Pseudomonas and Proteobacteria in the spikelet microbial community. Further study revealed that B3 altered the metabolites of spikelets, especially hordenine and l-aspartic acid, which played a key role in reshaping the microbiome and supporting the growth of the functional core microbe Pseudomonas, and inhibited the pathogen growth and mycotoxin production. This study provided a feasibility of regulating the function of aboveground microbial communities by manipulating plant subsurface tissues to control disease and mycotoxin pollutants in agricultural production.