Impact of brassinosteroids on postharvest physiology of fruits and vegetables

Abstract The increasing demand for consumption of fresh fruits and vegetables, along with restriction on the use of synthetic chemicals on postharvest operations for alleviating postharvest chilling injury (CI) along with minimizing decay, has encouraged scientific research to develop new technologies based on natural products such as brassinosteroids (BRs). Membrane damage and reactive oxygen species production are multifarious adverse effects of chilling with oxidative facet in fruits and vegetables. Alleviating chilling in fruits and vegetables treated with BRs could be attributed to (1) enhancing membrane integrity by reducing phospholipase D and lipoxygenase enzyme activities and increasing the unsaturated fatty acid/saturated fatty acid ratio, (2) enhancing antioxidant system activity, and (3) alteration in phenylalanine ammonia-lyase (PAL) and polyphenol oxidase enzyme activities. It can be presumed that the innovative postharvest BRs treatments not only alleviate postharvest CI along with minimizing decay but also enhance the nutritional quality of fruits and vegetables. With regard to postharvest decay, BRs treatment reduced disease incidence in fruits and vegetables, which was associated with H 2 O 2 accumulation. Also, fruits and vegetables treated with BRs exhibited higher expression of PR genes such as chitinase and PAL, which led to the suggestion that BRs generate pathogen resistance by activating systemic acquired resistance. BRs as an environmentally friendly safe regulator can be used not only for minimizing postharvest losses by alleviating CI along with reducing decay but also for maintaining nutritional quality of fruits and vegetables.