Potential Mechanism of Paenibacillus Kribbensis in Boosting Sesame Productivity and Pathogen Defense Through Metabolic Reprogramming of Flavonoid and Carbon Fixation Pathways

ABSTRACT Sesame (Sesamum indicum) is a key oilseed crop in China that benefits from eco‐friendly microbial agents for growth promotion and disease control; however, the precise molecular interactions between sesame and these agents remain elusive. This study investigated the microbial agent “Hangtianbao”(HTB), formulated with Paenibacillus kribbensis ΔPS04‐17, in a field‐grown sesame system over a single growing season. The experiment included three field plot replicates per group, with consistent field management except for HTB application, which was conducted four times at intervals, alternating between root drenching and foliar spraying. HTB significantly improved key agronomic traits, including single root fresh weight and seed number per pod, while increasing plot yield (0.14 ± 0.01 kg/m2) and total fat yield per plant (3.84 ± 0.50 g/plant), which were significantly higher than those of the CK group (0.09 ± 0.01 kg/m2 and 1.55 ± 0.26 g/plant). It also reduced incidence of Ralstonia solanacearum (4.79% ± 0.90%) and Macrophomina phaseolina (2.62% ± 0.40%) compared with the CK group (8.74% ± 0.52% and 5.08% ± 0.38%). Integrated transcriptomic and metabolomic analyses suggested potential associations between HTB application and changes in three core metabolic pathways: flavonoid biosynthesis, putatively associated with upregulation of the Chalcone Isomerase gene and accumulation of defensive metabolites; photosynthetic carbon fixation, putatively related to elevated expression of key genes such as rbcL and rbcS; and fatty acid synthesis, putatively correlated with upregulation of the FabG gene. These preliminary correlative findings provide important insights into microbial‐mediated crop improvement and support the development of sustainable agricultural practices.