Metabolomics and physiological analyses validates previous findings on the mechanism of response to wounding stress of different intensities in broccoli.

• Metabolomics was used to explore the wounding-responsive mechanisms in broccoli. • Reveals the global metabolites levels in broccoli with different wounding intensities. • This investigation found that the purine metabolism induced by wounding in broccoli. • This study validated the plant hormone signaling induced by wounding in broccoli. • Validated that biosynthesis of secondary metabolites induced by wounding in broccoli. The mechanism of response of plant to wounding stress is a complex process that physiologically modifies the wounded tissue for protection. In this study, untargeted metabolomics and physiological analyses were performed to validate the molecular mechanism of response to wounding stress of two intensities (0.04 and 1.85 m2 kg−1) in broccoli florets and shreds, respectively. The results showed that 97 and 1220 differentially expressed metabolites could be identified in broccoli subjected to the Florets vs. Control and Shreds vs. Control experiments, respectively. The Kyoto Encyclopedia Genes and Genomes pathway analyses revealed that these metabolites were mainly involved in aminoacyl-tRNA, amino acid, and secondary metabolite biosynthesis; purine metabolism; and plant signal molecule production. This study validated that wounding stress induced plant signal molecule production. Activation of jasmonic acid biosynthesis and H 2 O 2 production were more susceptible to wounding stress of higher intensities, whereas induction of salicylic acid biosynthesis and O 2 − production were more susceptible to wounding stress of lower intensities. Furthermore, wounding stress also activated glucosinolate and phenylpropanoid biosynthesis by regulating the levels of the precursors, including L-leucine, phenylalanine, tyrosine, valine, isoleucine, tryptophan, methionine, and phenylalanine. Wounding stress induced phenylpropanoid biosynthesis and the antioxidant system by upregulating the corresponding critical enzyme activity and gene expression, contributing greatly to the enhancement of phenolic compound levels, free radical scavenging ability, and resistance to wounding in broccoli. [ABSTRACT FROM AUTHOR]