关键词: 刺葡萄, 细胞培养, 类黄酮3′5′-羟化酶, 花青素, 过表达

Abstract:

【Objective】This study aims to clone the key gene VdF3′5′H2 involved in anthocyanin biosynthesis and analyze its regulatory role of anthocyanin biosynthesis and component content in spine grape (Vitis davidii Foëx) cells, thereby providing technical support and a theoretical foundation for constructing spine grape cells with high-yield anthocyanin production and enabling targeted regulation of anthocyanin biosynthesis.【Method】Using spine grape cells as materials, the VdF3′5′H2 was cloned and a plant expression vector was constructed. This vector was subsequently transformed into spine grape cell, with positive cell lines were screened in antibiotic media and identified through fluorescence observation and PCR analysis. The phenotypic characteristics of the transgenic spine grape cells were analyzed, along with quantification of anthocyanin, flavonoid, and proanthocyanidin. Additionally, the metabolite profile of anthocyanins was detected by UPLC-MS/MS. The expression levels of genes associated with anthocyanin biosynthesis were assessed using real-time quantitative PCR (RT-qPCR), and a comprehensive analysis of gene expression and differential metabolites was carried out by the O2PLS method.【Result】The open reading frame (ORF) of VdF3′5′H2 gene is 1 527 bp, encoding a protein comprising 508 amino acid residues. The VdF3′5′H2 protein exhibits high homology with its counterparts in related plants within the same family, containing the CYP75 conserved domain, a heme-binding site, and three characteristic conserved motifs. Phylogenetic analysis revealed that F3′H and F3′5′H cluster within the same branch, implying an evolutionary relationship from F3′H to F3′5′H, with VdF3′5′H2 positioned at a more ancestral state compared to VdF3′5′H1. Furthermore, subcellular localization indicated that the VdF3′5′H2 protein resides in the cytoplasm. The contents of anthocyanins, flavonoids and proanthocyanidins in two transgenic spine grape cells overexpression VdF3′5′H2 showed a significant increase compared to the wild type control. The content ratio of delphinidin-anthocyanins in the two transgenic cells increased to 7.82% (T6) and 14.32% (T10), respectively, Petunidin-anthocyanins increaseed to 7.30% and 10.16%, respectively, while the content ratio of malvidin- anthocyanins increased to 58.08% and 42.30%, respectively. In contrast, the content ratios of the three types of anthocyanins in the wild-type cells were 1.92%, 1.48%, and 8.49%, respectively. Additionally, the content ratios of cyanidin- and paeonidin-anthocyanins in the two transgenic cells decreased significantly. Overexpression of VdF3′5′H2 led to the downregulation of PAL, CHS, CHI and F3H expression levels, while upregulating the expression levels of VdF3′5′H1, LDOX and UFGT genes. The comprehensive analysis integrating gene expression data with differential metabolites showed that the overexpression of VdF3′5′H2 modulated the transcriptional regulation of genes involved in anthocyanin biosynthesis, thereby influencing both the synthesis pathways and accumulation patterns of various types of anthocyanins.【Conclusion】The overexpression of VdF3′5′H2 gene significantly enhanced the biosynthesis and accumulation of anthocyanins in spine grape cells, by regulating gene expression and altering the metabolic flux of the anthocyanin biosynthesis pathway, there by modulating the composition and content ratio of antocyanins in spine grape cells.

Key words: spine grape, cell culture, flavonoids 3′5′-hydroxylase (F3′5′H), anthocyanins, overexpression