Effects of Melatonin Treatment of Postharvest Pear Fruit on Aromatic Volatile Biosynthesis.

Jianlong Liu,Chengquan Yang,Zhigang Wang,Rui Zhai,Lingfei Xu,Fengwang Ma,Ting Wu,Hanting Liu

doi:10.3390/molecules24234233

Jianlong Liu, Chengquan Yang + Show 6 more

Open Access

https://doi.org/10.3390/molecules24234233

Copy DOI

Abstract

Aroma affects the sensory quality of fruit and, consequently, consumer satisfaction. Melatonin (MT) is a plant growth regulator used to delay senescence in postharvest fruit during storage; however, its effect on aroma of pear fruit remains unclear. In this study, we assessed the effects of 0.1 mmol L−1 MT on volatiles and associated gene expression in the fruit of pear cultivars ‘Korla’ (Pyrus brestschneideri Rehd) and ‘Abbé Fetel’ (Pyrus communis L.). MT mainly affected the production of C6 aromatic substances in the two varieties. In ‘Korla’, MT inhibited expression of PbHPL, and reduced hydroperoxide lyase (HPL) activity and content of hexanal and (E)-hex-2-enal. In contrast, MT inhibited activity of lipoxygenase (LOX), reduced expression of PbLOX1 and PbLOX2, promoted PbAAT gene expression, increased alcohol acyltransferase (AAT) activity, and increased propyl acetate, and hexyl acetate content in ‘Abbé Fetel’ that similarly led to the reduction in content of hexanal and (E)-hex-2-enal. Content of esters in ‘Abbé Fetel’ pear increased with increasing postharvest storage period. Although mechanisms differed between the two varieties, effects on aroma volatiles mediated by MT were driven by expression of genes encoding LOX, HPL, and AAT enzymes.

Highlights

Melatonin (MT) (N-acetyl-5-methoxytryptamine) is a nontoxic biological molecule produced by the pineal gland in animals and in different tissues in plants
There was no difference in the aroma maps of ‘Korla’ immediately after treatment (IAT) and at PRC (Figure S1a); substances were much richer at PRC than IAT for ‘Abbé Fetel’ (Figure S1b)
MT inhibited ethylene substances were much richer at PRC than IAT for ‘Abbé Fetel’ (Figure S1b)

Summary

Introduction

Melatonin (MT) (N-acetyl-5-methoxytryptamine) is a nontoxic biological molecule produced by the pineal gland in animals and in different tissues in plants. A range of treatments to maintain the quality and shelf life of postharvest fruit has been developed, including the application of MT that reduces. ROS activity, increases production of antioxidant enzymes during postharvest storage, and inhibits ethylene synthesis to delay ripening and softening [7].Exogenous application of MT to grapes on the vine changes their polyphenol metabolism, carbohydrate biosynthesis, and, importantly, ethylene signaling [8] that, when reduced, has been shown to improve antioxidant activity in cassava fruit [9]. Climacteric fruit, ripening is characterized an increase the climacteric pear fruit, and many studies have shown that aroma biosynthesis is dependent onis respiration rate, and a greater production of volatiles and ethylene.[11] Ripening of apple fruit the ethylene biosynthetic pathway

Methods

Results

Conclusion