Soluble sugars, organic acids and energy metabolism involved in the wound healing of muskmelons elicited by benzothiadiazole

Benzothiadiazole (BTH) is an analogue of salicylic acid, which can reduce the disease severity in many harvested horticultural products via inducing resistance. In this study, muskmelons (cv. Perfect) were used as the materials to investigate BTH dipping on the sugars, organic acids and energy metabolism during healing. Results demonstrated that BTH increased fructose, glucose and sucrose contents at wounds of muskmelons in the early stage of healing. Further, BTH enhanced the contents of pyruvic acid, malic acid, fumaric acid, α-ketoglutaric acid and succinic acid, but decreased citric acid content. BTH also increased nicotinamide adenine dinucleotide (NAD) and its reduced form (NADH) contents. Moreover, BTH up-regulated ATP synthase subunit β and CmAAC expressions, but down-regulated CmAOX1D, CmUCP and CmPM-ATPase expressions, thereby maintaining the higher levels of adenosine triphosphate (ATP) and energy charge (EC). Taken together, BTH could promote the levels of soluble sugars, organic acids and energy at muskmelon wounds, which provide carbon skeletons and energy required for synthesis, transportation and cross linking of precursors of suberin and lignin, contributing to the formation of healing tissue.