Exogenous Melatonin Treatment Induces Disease Resistance against Botrytis cinerea on Post-Harvest Grapes by Activating Defence Responses

Abstract

Botrytis cinerea seriously affects the value of post-harvest grapes. Melatonin can act as an exogenous regulator in the resistance of exogenous pathogens due to its antioxidant activity. An artificial inoculation trial was conducted to research the induced resistance mechanism of melatonin treatment using the table grape “Muscat Hamburg” (Vitis vinifera L. cv). Grapes were immersed with 0.02, 0.2, and 2 mmol/L melatonin, followed by B. cinerea suspension injections after 48 h. The results showed that the mycelial growth and spore germination of B. cinerea was not significantly inhibited by melatonin at different concentrations (0.02–2 mmol/L). However, post-harvest melatonin treatment inhibited the increase of disease incidence and severity of grey mould, induced the synthesis and accumulation of total phenols and flavonoids, reduced malondialdehyde generation, and inhibited an increase in cell membrane permeability. Meanwhile, defensive enzyme activities, including superoxide dismutase (SOD), peroxidize (POD), catalase (CAT), phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), chitinase (CHI), and β-1,3-glucanase, were significantly increased in fruits treated with exogenous melatonin. These results suggested that exogenous melatonin treatment could activate defence responses to combat the infection of B. cinerea in post-harvest grapes.

Evaluation of Preharvest Melatonin on Soft Rot and Quality of Kiwifruit Based on Principal Component Analysis

“…Total immersion of litchi in MT solution caused resistance by modifying phenylpropane and energy metabolism [ 15 ]. Similar findings have been confirmed for apples and grapes [ 16 , 17 ]. Previous studies discovered that the soft rot pathogen infects kiwifruit during the fruit’s growth and causes subsequent pathological changes [ 18 ]; a single postharvest treatment did not successfully prevent the occurrence of soft rot.…”

Metabolic Profiling and Molecular Mechanisms Underlying Melatonin-Induced Secondary Metabolism of Postharvest Goji Berry (Lycium barbarum L.)

“…The current study showed that exogenous MLT treatment reduced disease incidence and lesion expansion in goji fruit during postharvest storage. As a potential antifungal agent, exogenous MLT has been shown to play positive roles in combating pathogens and restricting the postharvest decay in grapes [33], blueberry fruit [25], papaya [34], cherry tomato [35], and apple fruit [36]. Exogenous MLT application to postharvest fruit enhances the content of endogenous MLT, which, in turn, regulates many physiological changes in the fruit, including quality changes, senescence deterioration, and stress tolerance [20].…”

Exogenous Melatonin Spray Enhances Salinity Tolerance in Zizyphus Germplasm: A Brief Theory

“… [ 85 ] Grape Muscat Hamburg Control of postharvest losses 0.02, 0.2 and 2 mM L −1 It can activate defense responses to combat the infection of serious diseases such as B. cinerea in postharvest grapes. [ 4 ] Pistachio Badami-Zarand Salinity 0, 25, 50, 75, 100, 125 and 150 μM L −1 Exogenous application was also linked with higher increase in nutrient uptake. It can also attenuate the salinity damage via enhancing anti-oxidation ability, osmotic activity-adjustment and polyamine biosynthesis.…”

“…The bombardment with agro-chemicals in order to obtain higher yields have adversely affected the fruit quality and disturbed food safety, and these are even threats to an eco-friendly environment. For sustainable fruit production, the application of eco-friendly treatments is effective in maintaining fruit quality and protection from environmental hazards [ 4 ]. Approximately 20% yield losses have been estimated in the biosphere because of the excessive amount of salts in the soil [ 1 ].…”