Genome-Wide Analysis of the Glutathione S-Transferase (GST) Genes and Functional Identification of MdGSTU12 Reveals the Involvement in the Regulation of Anthocyanin Accumulation in Apple

Anthocyanins have essential biological functions, affecting the development of horticultural production. They are synthesized in the cytoplasm through flavonoid metabolic pathways and finally transported into vacuoles for storage. Plant glutathione S-transferases (GSTs) are multifunctional enzymes involved in anthocyanin transportation. In this study, we identified 38 GSTs from the apple (Malus domestica) genome (HFTH1 Whole Genome v1.0) based on the sequence similarity with the GST family proteins of Arabidopsis. These MdGST genes could be grouped into nine chief subclasses: U, F, L, Z, T, GHR, EF1B gamma, TCHQD, and DHAR. The structures, motifs, three-dimensional models, and chromosomal distribution of MdGST genes were further analyzed. Elements which are responsive for some hormones and stress, and others that involve genes related to flavonoid biosynthesis were forecast in the promoter of MdGST. In addition, we identified 32 orthologous gene pairs between apple and Arabidopsis. These genes indicated that numerous apple and Arabidopsis counterparts appeared to be derived from a common ancestor. Amongst the 38 MdGST genes, MdGSTU12 was considerably correlated with anthocyanin variation in terms of extracting expression profiles from reported. Finally, further functional identification in apple transgenic calli and subcellular localization confirmed that MdGSTU12 was of great significance in anthocyanin accumulation in apple.

Automated summary

Anthocyanins play vital biological roles in plant growth and development, with GSTs being essential for their transportation. The study identified 38 GST genes in the apple genome and found 32 orthologous gene pairs between apple and Arabidopsis. MdGSTU12 was significantly correlated with anthocyanin variation in apple, indicating its importance in anthocyanin accumulation.