Flavonoids, abundant in the fruits, are pivotal to their growth, development, and storage. In addition, they have significant beneficial effects on human health. Consequently, research is increasingly concentrating on the regulatory mechanisms governing flavonoid biosynthesis in fruits. Phytohormones are involved in the regulation of flavonoid biosynthesis. The abscisic acid, ethylene, jasmonic acid, cytokinins, and brassinosteroids promote flavonoid biosynthesis, while auxin negatively regulates flavonoid biosynthesis. Subsequently, transcription factors from the MYB, bHLH, WRKY, NAC, and bZIP families are pivotal in regulating flavonoid biosynthesis. In addition, non-coding RNAs (microRNA and lncRNA) also participate in the regulation of flavonoids biosynthesis. MicroRNAs are generally believed to negatively regulate flavonoid metabolism in fruits, while lncRNAs have the opposite effect. Furthermore, the interactions between plant hormones, transcription factors, and non-coding RNAs in fruit flavonoid biosynthesis were analyzed. Ultimately, a foundational regulatory network for fruit flavonoid biosynthesis was hereby established.

In order to investigate the food nutrition and safety of potato, the objective of the present study is to quantify glycoalkaloids (α-chaconine and α-solanine) and phenolic compounds in three potato cultivars, namely, Russet Burbank, Atlantic, and Shepody, grown in Hebei, China, and these two classes of biologically active compounds in commercial dehydrated potato flakes were also investigated. The total glycoalkaloid levels in whole potatoes ranged from 4.72 mg/kg for Shepody potatoes to 34.45 mg/kg for Russet Burbank potatoes. The ratio of α-chaconine to α-solanine in whole potatoes ranged from 0.41 for Russet Burbank potatoes to 3.61 for Atlantic potatoes. The removal rate of total glycoalkaloids in Russet Burbank potatoes during dehydrated potato flake processing is 90.0%. Chlorogenic acid is the dominant phenolic compound in Russet Burbank potatoes. By contrast, Atlantic and Shepody potatoes contain considerable caffeic acid. The loss rate of phenolic compounds in Russet Burbank during dehydrated potato flake processing is 50.47%.