Blue light inhibits gray mold infection by inducing disease resistance in cherry tomato

Induced resistance is considered as a sustainable strategy to control postharvest decay of fruits, while light emitting diodes (LEDs) as a green physical technology are of more and more interest in postharvest fruit preservation field. In this study, we evaluated for the first time the resistance inducing ability of LED irradiation with different light wavelengths and photoperiods for cherry tomatoes (Solanum lycopersicum L. 'Qianxi'). Results indicated the exposure to 40 W m-2 of four light wavelengths for 3 d decreased B. cinerea lesion diameter on harvested cherry tomatoes, notably the best effect in blue light (470 nm). Meanwhile, the mechanism of blue light-induced disease resistance is the enhancement of defense-enzyme activity and the expression of defense-related genes. Moreover, results revealed that blue light enhanced vitamin C content and the firmness of the fruit exocarp, suggesting the potential usage of blue light in the postharvest preservation of cherry tomatoes.