Epiphytic bacterial consortia drive growth regulation in potato under methyl jasmonate elicitation: A leaf surface...

Methyl jasmonate (MeJA), a lipid-derived signaling molecule widely reported as a plant growth regulator, was revealed in this study to coordinate oxidative stress adaptation and delay senescence in potato through metabolite-microbe interactions, ultimately improving yield. MeJA triggered leaf oxidative stress while integrating rapid enzymatic scavenging, sustained osmoprotectant accumulation, and membrane stabilization, effectively delaying senescence initiation. Metabolic reprogramming under MeJA suppressed endogenous jasmonic acid synthesis while promoting saturated fatty acid biosynthesis, altering leaf surface lipid composition. These lipid changes, combined with MeJA-induced alkaloids, drove functional restructuring of phyllosphere epiphytic bacteria through fatty acid-mediated niche specialization, enhancing bacterial metabolism and enriching stress-resistant Proteobacteria. Notably, the enrichment of saturated fatty acids correlated with microbial taxa exhibiting specialized lipid metabolism. Field trials demonstrated that 200 μmol/L MeJA optimized redox homeostasis and photosynthetic longevity in early-maturing cultivar 'Favorita', translating delayed senescence into significant yield increases. This study proposes a "metabolite-guided microbial niche construction" model, where host lipid metabolism and secondary metabolites jointly shape stress-adapted microbial communities, providing new strategies for precision agrochemical design targeting phyllosphere microbiome engineering.