Synthetic Metabolites Derived From Host-Exudates Modulate the Bacterial Wilt Occurrence

Root exudate-mediated microbial community assembly is critical for host health and growth. However, disease-induced variations in plant-microbe interactions remain ambiguous. Here, we explored the intrinsic distinctions and interactions between the secretion patterns and microbial community composition of diseased and healthy tomatoes. Our results showed that rhizosphere microbial communities in healthy and diseased tomatoes were dominated by potentially beneficial genera ( Bacillus , Rhodanobacter , Pseudolabrys , Gemmatimonas , Dongia , and Bradyrhizobium ) and putative pathogens ( Ralstonia and Neocosmospora ), respectively, which were correlated with differential metabolites. Further metabolite addition experiments demonstrated the differential regulation mechanism of specific metabolites on host health. Drawing inspiration from synthetic communities, we displayed a way to construct the synthetic metabolites (SynMets), and we found that the SynMets (cortisol, quercetin, pyridoxal, and levodopa), which were enriched in healthy tomatoes could resist diseases by inhibiting pathogen growth and constructing beneficial microbial communities. Conversely, the SynMets (pyridoxine, N-benzylformamide, isoquinoline, and xanthine) enriched in diseased tomatoes could result in microbial imbalances by facilitating pathogen growth, thereby causing disease occurrence and growth limitation. In total, our research indicated the importance of SynMets-mediated pathogen reproduction and microbial community assembly for plant health and lays a foundation for targeted regulation of rhizosphere microecology through synthetic metabolites.