Investigating the Effect of Pipecolic Acid on Specialized Metabolites Involved in Tomato Plant Defense Mechanisms Against Ralstonia solanacearum Wilt Pathogens

The role of pipecolic acid (Pip) in plant immune responses, particularly against bacterial wilt pathogens, is significant. This research aimed to understand the interaction between plant defense-responsive enzymes and Pip by analyzing methanolic extracts from different treatments of tolerant (GAT5) and susceptible (GT2) tomato cultivars. LC-MS analysis demonstrated that the foliar application of Pip significantly influenced tomato metabolites, especially in bacterial wilt-infected plants, with a more pronounced effect in tolerant varieties. Principal component analysis (PCA) revealed that Pip-treated plants of tolerant varieties exhibited better coordinated metabolome profiles than those of susceptible varieties. Notable variations were observed in the levels of specialized metabolites, such as salicylic acid (SA), N-hydroxy pipecolic acid (NHP), and Pip, which are essential for producing defense compounds. Molecular docking studies further explored Pip’s interactions with key plant enzymes involved in defense mechanisms and showed that Pip acts as an effective organic inducer of systemic acquired resistance (SAR). These findings highlight Pip’s potential as a natural agent for enhancing plant tolerance to pathogens, offering promising implications for agricultural practices and improving crop resilience against diseases. This study enhances our understanding of Pip’s role in plant defense and provides a foundation for developing Pip-based strategies for sustainable agriculture.