Physiological response and proteomic profiling of biochar-induced tomato resistance to bacterial wilt

Biochar has been shown to enhance plant resistance against biotic stress, yet the underlying mechanisms remain unclear. In this study, influence of wheat straw biochar on disease development, plant physiology, and proteomic expression in tomato plants infected with Ralstonia solanacearum were evaluated. The results indicated that biochar application significantly improved plant growth, reduced the severity of disease, and decreased the colonization of R. solanacearum in tomato stems. Physiological analysis revealed that biochar treatment signif-icantly increased peroxidase and lipoxygenase activities, as well as the content of total soluble phenolics and lignin-like phenolic polymers in tomato leaves under pathogen infection. Moreover, proteomic analysis revealed that biochar treatment upregulated the expression of genes involved in lignin synthesis, anion channel and sulfur metabolism, and downregulated the expression of genes involved in microtubule and cytoskeleton organization, as well as UDP-glucose metabolism.In conclusion, our study demonstrates that biochar improves the resistance of tomato plants to bacterial wilt through enhancing lignin deposition, limiting pathogen movement, scavenging reactive oxygen species (ROS), and reducing the stress response that triggers early-stage plant defense.