Functional characterization of a glucosyltransferase gene, LcUFGT1, involved in the formation of cyanidin glucoside in the pericarp of Litchi chinensis

Abstract

Anthocyanins generate the red color in the pericarp of Litchi chinensis. UDP-glucose: flavonoid 3-O-glycosyltransferase (UFGT, EC. 2.4.1.91) stabilizes anthocyanidin by attaching sugar moieties to the anthocyanin aglycone. In this study, the function of an UFGT gene involved in the biosynthesis of anthocyanin was verified through heterologous expression and virus-induced gene silencing assays. A strong positive correlation between UFGT activity and anthocyanin accumulation capacity was observed in the pericarp of 15 cultivars. Four putative flavonoid 3-O-glycosyltransferase-like genes, designated as LcUFGT1 to LcUFGT4, were identified in the pericarp of litchi. Among the four UFGT gene members, only LcUFGT1 can use cyanidin as its substrate. The expression of LcUFGT1 was parallel with developmental anthocyanin accumulation, and the heterologously expressed protein of LcUFGT1 displayed catalytic activities in the formation of anthocyanin. The LcUFGT1 over-expression tobacco had darker petals and pigmented filaments and calyxes resulting from higher anthocyanin accumulations compared with non-transformed tobacco. In the pericarp with LcUFGT1 suppressed by virus-induced gene silencing, pigmentation was retarded, which was well correlated with the reduced-LcUFGT1 transcriptional activity. These results suggested that the glycosylation-related gene LcUFGT1 plays a critical role in red color formation in the pericarp of litchi.

Identification of MicroRNAs and Their Target Genes Related to the Accumulation of Anthocyanins in Litchi chinensis by High-Throughput Sequencing and Degradome Analysis

“…Previous studies indicated that the expression of LcUFGT , LcF3H , LcDFR , LcGST , and their regulatory gene LcMYB1 were up-regulated as the fruit developed toward full maturity (Wei et al, 2011; Lai et al, 2014; Li et al, 2015; Hu et al, 2016). In the present study, the expression of miR156a was enhanced with the accumulation of anthocyanins, while its target genes LcSPL1 / 2 were opposite ( Figures 3C,D ).…”

“…Apart from the delicious taste, attractive red skin of litchi is another important aspect of the fruit quality. Recently, the gene involved in anthocyanin biosynthesis and sequestration from litchi has been reported (Wei et al, 2011; Lai et al, 2014, 2015, 2016; Li et al, 2015; Hu et al, 2016). However, the mechanism of miRNAs regulating anthocyanin biosynthesis in litchi has not been reported.…”

Biochemical and functional characterization of AcUFGT3a, a galactosyltransferase involved in anthocyanin biosynthesis in the red‐fleshed kiwifruit (Actinidia chinensis)

“…Many regulation genes involved in anthocyanin biosynthesis have been identified in fruits such as peach (Tuan et al , Zhou et al ), grape (Kobayashi et al , Deluc et al , Hichri et al , Matus et al , Perez‐Diaz et al ), apple (An et al , Chagne et al ), pear (Wang et al , Zhai et al ), litchi (Lai et al , Lai et al ) and Myrica rubra (Liu et al , Huang et al ). However, few studies have reported on the functional characterization of the structural gene families in fruiting plants (Gonzalez et al , Cheng et al , Li et al ).…”

“…Glycosylation is known not only to stabilize anthocyanins but also to serve as a signal for their transport to the vacuole (Ono et al ); thus, it plays an important role in the accumulation of anthocyanins in plants. In addition, the expression of UFGT genes has been shown to be one of the most closely regulated steps in the anthocyanin biosynthetic pathway (Boss et al , Griesser et al , Cutanda‐Perez et al , Wang et al , Tuan et al , Li et al ). Plants with mutations in glycosyltransferases ( GTs ), such as bronze1 (Fedoroff et al ) and ANL1 (Kubo et al ), do not accumulate anthocyanins.…”

“…The genes encoding UFGTs in a range of species can be divided into two groups, based on their specificity for sugar acceptors. The first group is responsible for attaching a sugar to anthocyanin aglycones, including anthocyanidin 3‐ O ‐glycosyltransferase (Fedoroff et al , Tohge et al , Gonzalez et al , Zhao et al , Cheng et al , Li et al , Sun et al ) and anthocyanidin 5,3‐ O ‐glucosyltransferase (Ogata et al ). The second group is responsible for further glycosylation of anthocyanidin 3‐ O ‐glycosides, leading to the formation of diglycoside and these have been reported in petunia (Kroon et al ), Japanese morning glory (Morita et al ), daisy (Sawada et al ) and Arabidopsis thaliana (Yonekura‐Sakakibara et al ).…”