Identification of Anthocyanins-Related Glutathione S-Transferase (GST) Genes in the Genome of Cultivated Strawberry (Fragaria × ananassa).

Yuanxiu Lin,Yong Zhang,Mengyao Li,Jiahao Zhang,Lianxi Zhang,Ya Luo,Yunting Zhang,Yan Wang,Haoru Tang,Qing Chen,Xiaorong Wang

doi:10.3390/ijms21228708

Abstract

Anthocyanins are responsible for the red color of strawberry, they are a subclass of flavonoids synthesized in cytosol and transferred to vacuole to form the visible color. Previous studies in model and ornamental plants indicated members of the glutathione S-transferase (GST) gene family were involved in vacuolar accumulation of anthocyanins. In the present study, a total of 130 FaGST genes were identified in the genome of cultivated strawberry (Fragaria × ananassa), which were unevenly distributed across the 28 chromosomes from the four subgenomes. Evolutionary analysis revealed the expansion of FaGST family was under stable selection and mainly drove by WGD/segmental duplication event. Classification and phylogenetic analysis indicated that all the FaGST genes were clarified into seven subclasses, among which FaGST1, FaGST37, and FaGST97 belonging to Phi class were closely related to FvRAP, an anthocyanin-related GST of wildwood strawberry, and this clade was clustered with other known anthocyanin-related GSTs. RNAseq-based expression analysis at different developmental stages of strawberry revealed that the expression of FaGST1, FaGST37, FaGST39, FaGST73, and FaGST97 was gradually increased during the fruit ripening, consistent with the anthocyanins accumulation. These expression patterns of those five FaGST genes were also significantly correlated with those of other anthocyanin biosynthetic genes such as FaCHI, FaCHS, and FaANS, as well as anthocyanin regulatory gene FaMYB10. These results indicated FaGST1, FaGST37, FaGST39, FaGST73, and FaGST97 may function in vacuolar anthocyanin accumulation in cultivated strawberry.

Highlights

Strawberry (Fragaria × ananassa) has been cultivated worldwide as one of the major fruit crops, it is highly regarded in the fresh fruit market mainly because of its attractive color, good flavor, and enrichment of nutrients
The results showed us that besides the three FaGST genes (FaGST1, FaGST39, and FaGST97) clustered into the anthocyanin-related clade, the expression of FaGST37 and FaGST73 largely increased at the initial red (IR) stage, when the anthocyanin started accumulating (Figure 7), indicating the expression of these five genes might contribute to the strawberry coloring
The results showed that all of the five putative anthocyanin-related FaGST genes showed the similar expression pattern with RNAse profiles, and the other six FaGST genes comprised continuous low expression levels at different developmental stages, except FaGST111, which showed a large increase at full red (FR) stage, indicating it might be involved in strawberry anthocyanin accumulation

Summary

Introduction

Strawberry (Fragaria × ananassa) has been cultivated worldwide as one of the major fruit crops, it is highly regarded in the fresh fruit market mainly because of its attractive color, good flavor, and enrichment of nutrients. Overexpression of MaF3 H from apple in Arabidopsis and tobacco resulted in red seedlings and flowers, respectively [5], while silencing of FaDFR [6] or FaF3H [7] in strawberry has resulted in complete loss of red color in fruits. Besides these enzymatic biosynthesis reactions, the transcriptional regulators of anthocyanin accumulation have been well studied, especially the ‘MBW’ complex consisting of MYB, basic helix-loop-helix (bHLH), and WD40-repeat proteins (WD) [8,9]. Evidence has shown that glutathione S-reductases (GSTs) are involved in anthocyanins transportation

Methods

Results

Conclusion