Physiological and Transcriptomic Analysis Validates Previous Findings of Changes in Primary Metabolism for the Production of Phenolic Antioxidants in Wounded Carrots

Wounding induces the accumulation of phenolic compounds in carrot. This study uses physiological and transcriptomic analysis to validate previous findings relating primary metabolism and secondary metabolites in wounded carrots. Our data confirmed that increased wounding intensity strengthened the accumulation of phenolics accompanied by enhancing respiration and showed the loss of fructose and glucose and the increase of energy status in carrots. In addition, transcriptomic evaluation of shredded carrots indicated that the respiratory metabolism, sugar metabolism, energy metabolism, and phenolic biosynthesis related pathways, such as "citrate cycle (TCA cycle)", "oxidative phosphorylation" and "phenylpropanoid biosynthesis", were activated by wounding. Also, the differentially expressed genes (DEGs) involved in the conversion of sugars to phenolics were extensively up-regulated after wounding. Thus, the physiological and transcriptomic data validate previous findings that wounding accelerates the primary metabolisms of carrot including respiratory metabolism, sugar metabolism, and energy metabolism to meet the demand for the production of phenolic antioxidants.