Submitted to: Horticulture Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Blueberry is known as a super food with several health properties derived from chlorogenic acid and anthocyanin. Previous studies indicated that modifications of anthocyanin chemical structure and the amount of the chlorogenic acid could affect their level of adsorption and biological activity, respectively. Previous studies identified chromosomal regions and candidate genes controlling chlorogenic acid content, anthocyanin modification, promising opportunities to develop molecular breeding capacity for these compounds. To advance work toward this goal in this study a three-year experiment was performed to validate these chromosomal regions across the blueberry germplasm and a Virus-induced gene silencing approach was used to validate the function of the candidate genes controlling anthocyanin acylation. Notably, two major regions for the anthocyanin acylation and glucose specific glycosylation types of modifications were confirmed on chromosomes 2 and 4, respectively. Two candidate genes were identified as likely genes controlling anthocyanin acylation. Silencing these two genes resulted in a near zero detection of acylated anthocyanin as compared to 30% acylated anthocyanin accumulated in the non-silenced control. Overall, this study establishes the foundation to develop a molecular marker for higher acylated anthocyanin and functional characterization of genes associated with anthocyanin or other fruit related traits in blueberry.

Technical Abstract: Blueberry is known as a super food with several health properties derived from chlorogenic acid and anthocyanin. Previous studies indicated that modifications of anthocyanin chemical structure like acylation and the content of the chlorogenic acid could affect their level of adsorption and biological activity, respectively. Genetic studies identified major loci and candidate genes controlling chlorogenic acid content, anthocyanin acylation and glycosylation, promising opportunities to develop molecular breeding capacity for these bioactive. To advance work toward this goal in this study a three-year GWAS experiment was performed to validate anthocyanin and chlorogenic acid QTLs across the blueberry germplasm and a Virus-induced gene silencing approach was used to validate the function of the candidate genes controlling anthocyanin acylation. Notably, two major regions with overlapping QTLs for anthocyanin acylation and glucose specific glycosylation were confirmed on chromosomes 2 and 4, respectively, while no stable QTLs were identified for chlorogenic acid. RNASeq analysis identified two BADH acyltransferases named VcBAHD-AT1 and VcBAHD-AT4, as best candidate genes controlling anthocyanin acylation. Silencing these two genes resulted in a near zero detection of acylated anthocyanin as compared to 30% acylated anthocyanin accumulated in the non-silenced control. Overall, theis study establishes the foundation to develop a molecular marker for higher acylated anthocyanin and functional characterization of genes associated with anthocyanin or other fruit related traits in blueberry. Selecting new blueberry cultivars with higher acylated anthocyanin could potentially increase absorption of this health related bioactive. These outcomes represent a critical step to advance genetic studies and molecular breeding for anthocyanins in this crop.