Exogenous Melatonin and Abscisic Acid Expedite the Flavonoids Biosynthesis in Grape Berry of Vitis vinifera cv. Kyoho

Abstract

Grape polyphenols contributing to more than half of the global polyphenol market were well studied; however, how melatonin (MLT), a potential plant hormone, and abscisic acid (ABA) affects polyphenols profile is still poorly understood. To explore whether these hormones are involved in polyphenolic biosynthesis, grape (Vitis vinifera cv. Kyoho) was exposed to MLT, ABA, and NDGA (nordihydroguaiaretic acid, an ABA biosynthesis inhibitor) treatments, and 16 polyphenols were identified from grape extracts by high performance liquid chromatography quadrupole time of flight mass spectrometry (HPLC-Q-TOF-MS). Both exogenous MLT and ABA significantly enhanced the biosynthesis of each flavonol and flavanol component, especially catechin, which was almost increased double by 200 µM of MLT treatment. Furthermore, the expression of genes involved in flavonoid biosynthesis, including 4-coumaroyl-CoA synthase, chalcone synthase, flavonoid 3′-hydroxylase, anthocyanin 3′-methyltransferase, flavonol synthase, flavonoid-3-O-glucosyltransferase, and flavonoid 3′,5′-methyltransferase were highly up-regulated as well but were down-regulated by NDGA. The present study provided new insights for improving flavonoids accumulation in agricultural production and its underlying mechanism.

Metabolite and Transcriptome Profiling Analysis Revealed That Melatonin Positively Regulates Floral Scent Production in Hedychium coronarium

“…In Vitis vinifera cv. Kyoho, melatonin and ABA application triggered flavonoid biosynthesis by influencing the expression level of structural flavonoid biosynthesis genes (Yang et al, 2020). Our findings are in line with previous reports that melatonin significantly influenced the expression level of certain genes involved in several biological processes (Arnao and Hernández-Ruiz, 2019;Cecon et al, 2019).…”

“…ABA significantly increase flavonol accumulation by upregulating the expression of flavonoid biosynthesis genes (Yang et al, 2020). These results indicate that melatonin significantly triggered the mechanism of floral aroma production.…”

Melatonin Treatment Improves Postharvest Preservation and Resistance of Guava Fruit (Psidium guajava L.)

“…Treatment with melatonin substantially enhanced the accumulation of the content of lycopene and the production of ethylene in tomatoes, resulting in accelerated fruit ripening and an improvement in the quality of appearance of the tomato fruit [18]. Exogenous melatonin treatment on young grapes also significantly promoted the growth and increased the endogenous melatonin content of the fruit, significantly increasing the content of total anthocyanins, fruit total soluble solids and promoting the ripening of grapes [36]. This study demonstrates that treatment with melatonin could effectively delay the softening of guava fruit, which is consistent with most of the studies so far.…”

Melatonin alters the secondary metabolite profile of grape berry skin by promoting VvMYB14-mediated ethylene biosynthesis

“…Grapevine is one of the most important fruit crop species worldwide, and the quality of grape berries mainly depends on their primary and secondary metabolites; moreover, the chemical composition of berries is primarily influenced by secondary metabolites, including alkaloids, terpenes, phenolics, and volatiles 1 . Grape berries are a rich source of natural antioxidant compounds (mainly polyphenols) that contribute to more than half of the global polyphenol market 2 . Grape berries are nonclimacteric fruits, and several signaling molecules, including melatonin and ethylene, participate in berry metabolism and ripening regulation 3 , although the mechanism underlying the ripening of nonclimacteric fruits, including grape berries, remains largely unclear.…”