Blue LED light treatment inhibits virulence and patulin biosynthesis in Penicillium expansum

Abstract

Blue light-emitting diode (LED) light has been considered to influence the growth, quality, and preservation of certain fruit and vegetable. However, the blue LED light impact on apple postharvest blue mold remains elusive. In this study, the influence of blue LED light on Penicillium expansum virulence and patulin secretion was investigated in vitro and in vivo, as well as on the apple quality. The growth of P. expansum was inhibited by blue LED light via changes in mycelium morphology changes, cell membrane integrity, and potential mitochondrial membrane destruction, thereby causing reactive oxygen species accumulation, oxidative stress, and mitochondrial dysfunction. Furthermore, the expression level of LaeA relevant to the pathogenicity of P. expansum, was down-regulated. Specifically, the patulin production of P. expansum was inhibited via expression down-regulation of the patulin biosynthesis-related genes PatA, PatE, and PatN rather than direct degradation by the blue LED light treatment. Additionally, no significant effects on the fruit quality were observed when the light intensity was lower than 120 μmol m-2 s-1. In summary, blue LED light treatment has the potential for a low-cost, safe, and non-chemical approach to control apple postharvest decay.