CsGATA5-CsTRYS/CsTDC2 module coordinates tryptophan-mediated wound healing in postharvest citrus fruit

The wound healing process in postharvest citrus fruit represents a crucial physiological mechanism that effectively resists external stress and minimizes quality deterioration. Nevertheless, the molecular mechanisms involved in wound healing by GATA transcription factors in citrus remain largely unexplored. In this research, CsGATA5 was characterized as a newly identified transcriptional activator promoting wound healing in citrus fruit. Transient overexpression of CsGATA5 in tobacco also confirmed its role in promoting suberin accumulation. Gene expression and metabolite profiling analyses following CsGATA5 overexpression revealed that CsGATA5 activated pathways associated with amino acid metabolism during wound healing. DLR, EMSA, ChIP-qPCR, and Y1H assays demonstrated that CsGATA5 bound to the promoter regions of target genes in tryptophan metabolism (CsTRYS and CsTDC2), thereby activating their expression. Notably, the activation of CsTRYS and CsTDC2 genes during citrus wound healing contributed to the subsequent induction of downstream suberin biosynthesis. Moreover, the exogenous treatment of key metabolites of the amino acid pathway, including tryptophan, 5-hydroxytryptamine, and phenylalanine, significantly promoted wound healing and further supported a potential regulatory cascade of tryptophan metabolism- tricarboxylic acid cycle- suberin biosynthesis. This study sheds light on the molecular regulatory network by which GATA transcription factors modulate wound healing in fruit.