Transcription factor VvWRKY70 inhibits both norisoprenoid and flavonol biosynthesis in grape

Abstract

Norisoprenoids and flavonols are important secondary metabolites in grape berries (Vitis vinifera L.). The former is a class of ubiquitous flavor and fragrance compounds produced by the cleavage of carotenoids, and the latter, which is derived from the flavonoid metabolic pathway, has been proposed as a general quality marker for red grapes. However, the transcriptional regulatory mechanisms underlying norisoprenoid and flavonol production are still not fully understood. In this study, we characterized a transcription factor, VvWRKY70, as a repressor of both norisoprenoid and flavonol biosynthesis in grape berries, and its expression was down-regulated by light and high-temperature treatment. Overexpressing VvWRKY70 in grape calli reduced norisoprenoid and flavonol production, particularly under light exposure or at high temperature, by repressing the expression of several related genes in the isoprenoid and flavonoid metabolic pathways. VvWRKY70 downregulated β-CAROTENE HYDROXYLASE 2 (VvBCH2) and CHALCONE SYNTHASE 3 (VvCHS3) expression based on yeast one-hybrid analysis combined with electrophoretic mobility shift assay and chromatin immunoprecipitation-quantitative PCR. We discuss the role of VvWRKY70 in the coordinated regulatory network of isoprenoid and flavonoid metabolism. These findings provide a theoretical basis to improve flavor, color and other comprehensive qualities of fruit crops and their processing products.

Ethylene-responsive VviERF003 modulates glycosylated monoterpenoid synthesis by upregulating VviGT14 in grapes

“…For the gene overexpression experiment, ‘Cabernet Sauvignon’ calli were obtained following our previous reports [ 54 , 55 ]. The calli underwent culture on B5 solid medium, equipped with 3.21 g/L B5 basic medium, 30 g/L sucrose, 2.5 g/L acid-hydrolyzed casein, 0.2 mg/L kinetin, 0.1 mg/L 1-naphthyl acetic acid, and 3.0 g/L plant gel at pH 5.8 6.0 and kept in the dark at 25°C.…”

“…Table S5 (see online supplementary material) displays the primers used in the process, while further details can be found in Wei et al. ’s previous publication [ 54 ].…”

Transcriptional regulation of flavonol biosynthesis in plants

“…Overexpression of VqWRKY31 from Vitis quinquangularis in grape increased accumulation of flavonoids and stilbenes and promoted expression of VvCHS , VvCHI , VvDFR , VvFLS , and VvSTS (stilbene synthase), which enhanced powdery mildew resistance [ 79 ]. Moreover, VvWRKY70 was identified as a transcriptional repressor of flavonol biosynthesis in grape by inhibiting the transcriptional activity of VvFLS4 and VvCHS2/3 [ 80 ]. Overexpression of VvWRKY70 caused a reduction of flavonol contents in transgenic grape calli [ 80 ].…”

“…Moreover, VvWRKY70 was identified as a transcriptional repressor of flavonol biosynthesis in grape by inhibiting the transcriptional activity of VvFLS4 and VvCHS2/3 [ 80 ]. Overexpression of VvWRKY70 caused a reduction of flavonol contents in transgenic grape calli [ 80 ]. These WRKY TFs can directly regulate expression of FLS genes to participate in regulation of flavonol biosynthesis.…”

Metabolite and transcriptome analyses reveal the effects of salinity stress on the biosynthesis of proanthocyanidins and anthocyanins in grape suspension cells

“…Confirmed by transgenic grape suspension cells, VvNAC17 is an activator of both PA and anthocyanin pathways ( Badim et al., 2022 ). Recently, Wei et al. (2023) found that VvWRKY70 is a bi-functional transcription factor that simultaneously represses norisoprenoid and flavonoid biosynthesis.…”