Identification and characterization of HCT genes in blackberry: Overexpression of RuHCT1 enhances anthocyanin contents

Abstract

Emerging as a new generation of economic fruit, blackberries are rich in flavonoids and anthocyanins. Acylation can change the pharmacological activity and structural stability of anthocyanins and is of great significance to plant growth and secondary metabolism. In this study, based on the transcriptome data of the blackberry fruit, five blackberry hydroxycinnamoyl transferase (HCT) genes were screened and identified, all of which belong to the BAHD superfamily. Among them, RuHCT1, RuHCT2 and RuHCT3 have similar tertiary structures and functions. RuHCT1, the gene with the largest difference in expression between immature and mature blackberry fruits, was selected for overexpression research. The results showed that the content of anthocyanin in the leaves of transgenic plants was significantly increased, while the content of secondary metabolites such as lignan and chlorogenic acid was decreased. Moreover, the expression levels of the NtCCOMT, NtCHS and NtCYP98A genes in transgenic tobacco were lower than those in nontransgenic plants. In conclusion, RuHCT1 may be an important structural gene regulating anthocyanin synthesis in blackberry. RuHCT1 may also inhibit lignan synthesis and affect the expression of other key structural genes. This study provides a theoretical reference regarding the biosynthesis and regulatory mechanisms of anthocyanins in blackberry, contributing to the breeding of new blackberry cultivars with high anthocyanin content.