Diverse biological effects of glycosyltransferase genes from Tartary buckwheat

Panfeng Yao,Yunji Huang,Guanlan Shi,Qi Li,Simon Stael,Qi Wu,Hui Chen,Qixin Dong,Haixia Zhao,Renyu Deng,Bingbing Lv,Jiaqi Shi,Chenglei Li

doi:10.1186/s12870-019-1955-z

Abstract

BackgroundTartary buckwheat (Fagopyrum tataricum) is an edible cereal crop whose sprouts have been marketed and commercialized for their higher levels of anti-oxidants, including rutin and anthocyanin. UDP-glucose flavonoid glycosyltransferases (UFGTs) play an important role in the biosynthesis of flavonoids in plants. So far, few studies are available on UFGT genes that may play a role in tartary buckwheat flavonoids biosynthesis. Here, we report on the identification and functional characterization of seven UFGTs from tartary buckwheat that are potentially involved in flavonoid biosynthesis (and have varying effects on plant growth and development when overexpressed in Arabidopsis thaliana.)ResultsPhylogenetic analysis indicated that the potential function of the seven FtUFGT proteins, FtUFGT6, FtUFGT7, FtUFGT8, FtUFGT9, FtUFGT15, FtUFGT40, and FtUFGT41, could be divided into three Arabidopsis thaliana functional subgroups that are involved in flavonoid biosynthesis of and anthocyanin accumulation. A significant positive correlation between FtUFGT8 and FtUFGT15 expression and anthocyanin accumulation capacity was observed in the tartary buckwheat seedlings after cold stress. Overexpression in Arabidopsis thaliana showed that FtUFGT8, FtUFGT15, and FtUFGT41 significantly increased the anthocyanin content in transgenic plants. Unexpectedly, overexpression of FtUFGT6, while not leading to enhanced anthocyanin accumulation, significantly enhanced the growth yield of transgenic plants. When wild-type plants have only cotyledons, most of the transgenic plants of FtUFGT6 had grown true leaves. Moreover, the growth speed of the oxFtUFGT6 transgenic plant root was also significantly faster than that of the wild type. At later growth, FtUFGT6 transgenic plants showed larger leaves, earlier twitching times and more tillers than wild type, whereas FtUFGT15 showed opposite results.ConclusionsSeven FtUFGTs were isolated from tartary buckwheat. FtUFGT8, FtUFGT15, and FtUFGT41 can significantly increase the accumulation of total anthocyanins in transgenic plants. Furthermore, overexpression of FtUFGT6 increased the overall yield of Arabidopsis transgenic plants at all growth stages. However, FtUFGT15 shows the opposite trend at later growth stage and delays the growth speed of plants. These results suggested that the biological function of FtUFGT genes in tartary buckwheat is diverse.

Highlights

Tartary buckwheat (Fagopyrum tataricum) is an edible cereal crop whose sprouts have been marketed and commercialized for their higher levels of anti-oxidants, including rutin and anthocyanin
Screening of FtUFGT genes in tartary buckwheat To further study the UDP-glucose flavonoid glycosyltransferase (UFGT) involved in flavonoid synthesis in tartary buckwheat, we used uridine diphosphate (UDP)-glucose: flavonoid 3-O-glucosyltransferase as a probe to screen the transcriptome of tartary buckwheat [19]
The ORF of seven FtUFGTs was transferred into Arabidopsis thaliana, and the results indicated that FtUFGT8, FtUFGT15, and FtUFGT41 significantly increased total anthocyanin accumulation in transgenic plants (Fig. 4)

Summary

Introduction

Tartary buckwheat (Fagopyrum tataricum) is an edible cereal crop whose sprouts have been marketed and commercialized for their higher levels of anti-oxidants, including rutin and anthocyanin. Colorless co-pigments, affect the brightness and brilliance of colors and play vital roles in pollen germination [2] Because of these properties, the potential applications of flavonoids have drawn much research and commercial attention in recent years [3]. Phylogenetic analyses of the UFGTs showed that these enzymes can be classified into three different groups-UF3GT, UF5GT, and UF7GT-based on the regioselectivity of flavonoid glycosylation [14, 15] Such incongruence between the phylogenetic position and substrate specificities has been found in other UGTs, including grape VLOGT2, onion UGT73G1 and UGT73J1 [16]. The biological functions of UFGTs in plants are complex and diverse, and the coupling of phylogenetic analyses with experimental analyses is normally regarded as the most efficient and accurate method to identify UGT proteins

Methods

Results

Discussion

Conclusion