Effects of 5-aminolevulinic acid on Anthocyanin synthesis in Vitis Vinifera ‘Crimson Seedless’ grapes at the transcriptomics level

Abstract

In order to study the effect of exogenous 5-aminolevulinic acid (ALA) on the expression of genes associated with anthocyanin biosynthesis in the transcriptome of ‘Crimson Seedless’ grape (Vitis vinifera) peel, sequencing technology was used to compare the transcriptomes from water and ALA treated ‘Crimson Seedless’ grapes. Transcriptome sequencing was performed at two periods (d5 and d15) after peel treatment. The enrichment analysis of the Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathways indicated that the metabolic pathways induced by exposure to ALA were mainly the phenylpropanoid biosynthesis, flavonoid biosynthesis, anthocyanin biosynthesis, phenylalanine metabolism, and plant hormone signal transduction pathways. In the anthocyanin synthesis pathway, ALA treatment appeared to mainly regulate the phenylalanine ammonia-lyase, cinnamate 4-hydroxylase and chalcone synthase genes in the upstream pathway of anthocyanin synthesis, and the dihydroflavonol-4-reductase gene in the downstream pathway, with the effect being most obvious at d5.This study reveals the mechanism by which exogenous ALA promotes anthocyanin synthesis at the molecular level, and lays the foundation for further study of the physiological role of ALA.