UV-C irradiation accelerated the deposition of suberin and lignin at wounds by activating phenylpropanoid metabolism in potato tubers

Abstract

UV-C could directly inactivate pathogens, and reduce postharvest diseases of fruits and vegetables by inducing resistance. To date, no studies have been carried out to verify whether UV-C may accelerate the wound healing of potato tubers. The present results demonstrated that UV-C irradiation up-regulated StPAL, St4CL, and StCAD expression and activated phenylalanine ammonia-lyase (PAL), 4-coumarate: coenzyme A ligase (4CL), and cinnamyl alcohol dehydrogenase (CAD). Meanwhile, UV-C irradiation elevated the levels of four phenolic acids (p-coumaric acid, caffeic acid, sinapic acid, and ferulic acid) and three lignin monomers (coniferyl alcohol, sinapyl alcohol, and p-coumaryl alcohol), and accelerated the suberin polyphenolic (SPP) and lignin accumulation at wounds, thereby decreasing weight loss and disease index. The weight loss and disease index in the UV-C irradiated tubers were 36.48% and 56.25% lower than that of the control on the 14 d of healing, respectively. Taken together, UV-C irradiation promoted the process of wound healing in potato tubers by stimulating phenylpropanoid metabolism as well as accelerating the SPP and lignin accumulation at wounds. Therefore, UV-C irradiation could be employed as a simple, safe, and low-cost handling technology for accelerating wound healing of potato tubers.