Hydroxycinnamic acid amides emerge as multifunctional molecules involved in regeneration and volatile signalling during wound responses in tomato

Abstract

O_LIHydroxycinnamic acid amides (HCAAs) are phenylpropanoid-derived metabolites with known antimicrobial and structural roles in plant defence against pathogens. However, their contribution to mechanical wound responses remains unclear, especially in terms of tissue regeneration and signalling. C_LIO_LIHere, we used tomato transgenic plants overexpressing the tyramine hydroxycinnamoyl transferase (THT), the key biosynthetic enzyme for HCAA production, to investigate the role of HCAAs in wound-induced responses, combining targeted metabolite profiling, gene expression, confocal microscopy, antioxidant assays, and volatile analyses. C_LIO_LIWe show that THT overexpression enhances wound-induced accumulation of HCAAs, promoting vascular lignification, suberization, callose deposition, and increased regeneration capacity. Additionally, 35S::THT plants display a distinct VOC profile that modulates defence gene expression in neighbouring wild-type plants, even in the absence of injury. C_LIO_LIThese results identify THT as a key regulator of structural reinforcement and defence priming after mechanical damage. Our findings highlight a novel role for HCAAs in wound healing and interplant signalling, with potential applications for improving crop resilience to mechanical stress. C_LI