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.

Texture is a critical quality attribute of strawberry fruit, and phytohormones play a pivotal role in fruit softening, which mainly results from cell wall metabolism, which is governed by genes and enzymes. To gain further insights into strawberry (Fragaria × ananassa, Duch. cv. Akihime ) softening, our study investigated changes across five stages in fruits in their firmness, soluble solids content (SSC), cell microstructure, cell wall materials, activities of cell wall-modifying enzymes, gene expression, endogenous phytohormone levels, and their correlation. During strawberry ripening, firmness decreased, while SSC, intercellular space, and separation of the cell wall from the plasma membrane increased. Meanwhile, the contents of ionic pectin (ISP) and cellulose (CE), pectin methylesterase (PME) activity, FaPME expression, and the levels of zeatin (Z) and strigolactone (SL) decreased, showing a positive correlation with firmness. In contrast, the activities of pectate lyase (PL) and cellulase (Cx), the expression of FaPL and FaCx, and the contents of gibberellin A₄ (GA₄), GA₉, and abscisic acid (ABA) increased during ripening, and these were negatively correlated with firmness. These results suggest that Z and SL are associated with the maintenance of cell wall integrity and firmness, whereas increases in GA₄, GA_9, and ABA are linked to enhanced cell wall disassembly and fruit softening.

Metabolic syndrome (MetS) is a global health problem, and EPA/DHA-enriched phospholipids (EPA/DHA-PLs) have been found to have positive effects on MetS improvement. Currently, research on EPA/DHA-PL mainly focuses on special and rare seafood, such as phospholipids derived from krill, sea cucumber, squid, and fish roe. However, it has been recently demonstrated that abundant EPA/DHA-PL can also be found in bulk fish and its by-products. Nonetheless, there is still limited research on the biological activities of EPA/DHA-PL derived from these sources. The aim of this study was to investigate the effect of phospholipid extracts from the heads of salmon and silver carp (S-PLE and SC-PLE) on the high-fat-diet-induced MetS in C57/BL mice. After an 8-week intervention, both SC-PLE and S-PLE had a significant ameliorating effect on MetS. Moreover, SC-PLE was more effective than S-PLE in reducing liver inflammation and fasting glucose. Both of the PL extracts were able to regulate the expression of key genes in lipid synthesis, fatty acid β-oxidation, and insulin signaling pathways. Compared with S-PLE, dietary SC-PLE had a greater influence on liver metabolomics. Pathway enrichment analysis showed that the differential metabolites of SC-PLE were mainly involved in arachidonic acid metabolism and glutathione metabolism. The results indicated that the different metabolic regulation methods of S-PLE and SC-PLE could be related to their variant molecular composition in EPA/DHA-PL.