Stimulatory effect of bunch thinning on sugar accumulation and anthocyanin biosynthesis in Shenhua grape berry (Vitis vinifera×V. labrusca)

Abstract

Background and Aims Bunch thinning (BT) is a cultivation approach that strongly influences sugar and anthocyanin accumulation in grapes. Until now, little has been reported describing its underlying mechanisms. The aim was to explore the impact of BT on berry composition, enzyme activity, anthocyanin biosynthesis and gene expression from veraison to harvest in Shenhua grape berries. Methods and Results Vines cultivated in a greenhouse were selected and randomly divided into a Control group and a BT group in which half of the total bunches of each vine were removed 1 week before veraison. Bunch thinning positively influenced the sugar concentration, which could be attributed to the enhanced activity of acid invertase and sucrose synthase (cleavage direction). Bunch thinning also increased the anthocyanin concentration of berry skins significantly, which might be related to the positive upregulation of the expression of most genes involved in anthocyanin biosynthesis. Moreover, the downregulation of F3′H and upregulation of F3′5′H may be responsible for the observed shift of the anthocyanin composition under BT. Conclusion Bunch thinning increased both the sugar accumulation and anthocyanin biosynthesis and positively upregulated the activities of two enzymes, as well as the expression of most of the genes related to anthocyanin biosynthesis. Significance of the Study These findings provide insight into the effect of BT on the sugar accumulation and anthocyanin biosynthesis of grape berries.

Influence of cluster thinning and girdling on aroma composition in ‘Jumeigui’ table grape

“…In this study, and in previous studies, girdling at the beginning of véraison advances fruit ripening and increase soluble solids with no yield reduction 22,26,27 . Likewise, cluster thinning significantly increased TSS of 'Jumeigui' berries consistent with previous studies 16,[28][29][30] . Interestingly, in this study, TSS in thinned groups was significantly greater than that in girdled groups.…”

Carbon starvation reduces carbohydrate and anthocyanin accumulation in red‐fleshed fruit via trehalose 6‐phosphate and MYB27

“…The MBW complex activity can be modulated by repressors, including R2R3‐MYB repressors (subgroup 4), which actively inhibit transcription through repressive motifs (EAR and TLLLFR; Dubos et al, ), and competitive inhibitors, such as R3‐MYBs (Albert et al ) and SQUAMOSA‐PROMOTER BINDING PROTEIN‐LIKE genes ( SPL s; Gou et al, ). Carbohydrates, particularly sugars, also have a role in inducing anthocyanin accumulation by interacting with the MBW complex genes in plant species such as Arabidopsis (Solfanelli et al ), potato ( Solanum tuberosum , Payyavula et al, ), and grape ( Vitis vinifera , Dai et al, ; Xi et al, ). Expression of Arabidopsis MYB75/PAP1 (At1g56650), a gene coding for an R2R3‐MYB activator that regulates anthocyanin synthesis, has been shown to be modulated by exogenous sucrose feeding of vegetative tissues (Solfanelli et al ; Teng et al ) via a sequence/motif in the first intron of the gene (Broeckling et al ).…”

“…The MBW complex activity can be modulated by repressors, including R2R3-MYB repressors (subgroup 4), which actively inhibit transcription through repressive motifs (EAR and TLLLFR; Dubos et al, 2008), and competitive inhibitors, such as R3-MYBs (Albert et al 2014) and SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE genes (SPLs; Gou et al, 2011). Carbohydrates, particularly sugars, also have a role in inducing anthocyanin accumulation by interacting with the MBW complex genes in plant species such as Arabidopsis (Solfanelli et al 2006), potato (Solanum tuberosum, Payyavula et al, 2013), and grape (Vitis vinifera, Dai et al, 2014;Xi et al, 2018).…”

Burdock fructooligosaccharides inhibits postharvest colour development in grape skins by altering phenylpropanoid fluxes from anthocyanin to the resistance‐related phenolic substances

“…In grapes, different regulators belonging to the MYB transcription factor superfamily were reported to regulate structural genes on specific branches of the flavonoid pathway; MYBA1 (Kobayashi et al ), MYBA2 (Xi et al ) and MYB4 (de Rosas et al ) were reported to regulate the anthocyanin branch. In this study, the expression of MYBA1 and MYBA2 corresponded with DFR and UFGT during storage (Figure a–c).…”

“…Then, the anthocyanin biosynthesis pathway follows p ‐coumaroyl‐CoA, and chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3‐hydroxylase (F3H), flavonoid 3′‐hydroxylase (F3′H), flavonoid 3′, 5′‐hydroxylase (F3′5′H), dihydroflavonol 4‐reductase (DFR), leucocyanidin oxygenase (LDOX) and flavonoid‐3‐O‐glycosyltransferase (UFGT) catalyse the transformation of the intermediate product p ‐coumaroyl‐CoA into anthocyanins (Villegas et al ). Different regulators belonging to the MYB transcription factor superfamily have been reported to regulate structural genes on specific branches of the flavonoid pathway; MYBA1 (Kobayashi et al ), MYBA2 (Xi et al ) and MYB4 (de Rosas et al ) have been reported to regulate the anthocyanin branch and, thus, they are analysed in this study.…”