Hordenine and L-aspartic acid stimulated by Endophytic fungi reshaped rice spikelet microbiota to support plant against Fusarium spikelet rot disease

Rice spikelet rot disease (RSRD) is the main late disease caused by Fusarium proliferatum that seriously reduces the yield and quality of rice in China. Plant-related microorganisms have been shown to be relevant to plant health. Endophytic fungus Phomopsis liquidambaris reduces RSRD incidence and toxin accumulation, however, whether endophytic fungi drive healthy spikelet community assembly to enhance plant disease resistance remain large elusive. In this study, the incidence of RSRD and the content of fumonisin treated with endophytic fungus B3 was reduced by 21.5%, and 38.01%. Microbiome features suggested the endophytic fungal B3 significantly reduced the abundance of pathogen fungi, and remarkably enriched Pseudomonas and Proteobacteria in the spikelet microbial community after infection. Non-targeted metabolomics and culture-dependent methods revealed that endophytic fungus B3 altered the level of rice spikelet metabolites to drive resistance microbial community assembly. Here, we found that hordenine and L-aspartic acid played key roles in reshaping the microbiome, and supporting the growth of the functional core microbe Pseudomonas with superimposed effects on disease control. In addition, the increased of multiple active resistant metabolites also enhance rice resistance to against pathogen. Overall, our study reveals the key role by beneficial plant microbes stimulating the change of plant metabolites and mediating the assembly of resistant microbial communities in rice spikelet. This study helps us to better understand the interrelationship between beneficial microorganisms-plants-pathogens.