Researchers from North Carolina State University and collaborating institutes reported new findings on the enzyme acyltransferase genes that control anthocyanin acylation in blueberries.
The study, published in Horticulture Research, used a genome-wide association study combined with functional gene-silencing experiments in fruit tissues.
The team identified two acyltransferase genes, VcBAHD-AT1 and VcBAHD-AT4, that control the acylation of anthocyanins in blueberry.
The researchers' findings provide a molecular framework for improving the stability and health-related properties of blueberry pigments.
Blueberries are widely regarded as a functional food due to their high concentrations of anthocyanins and chlorogenic acid.
Yet, not all anthocyanins behave identically; their bioavailability, colour retention and metabolic fate depend on how the molecules are structurally decorated.
In particular, acylated anthocyanins are known to be more stable and may be more efficiently absorbed.
However, the genetic mechanisms controlling this acylation remain poorly understood, complicating targeted breeding efforts.
Based on these challenges, there is a critical need to identify the genes that regulate anthocyanin acylation and to clarify their biological roles.
The study analysed metabolic and genomic variation across 153 blueberry accessions to identify loci linked to anthocyanin composition.
A strong and stable quantitative trait locus associated with anthocyanin acylation was located on chromosome two.
Within this region, five BAHD-family acyltransferase candidates were examined through phylogenetic and transcriptomic comparison.
Two genes — VcBAHD-AT1 and VcBAHD-AT4 — were specifically expressed in fruit containing high levels of acylated anthocyanins.
To validate their function, the researchers developed an optimised virus-induced gene silencing (VIGS) system capable of suppressing these genes throughout the whole fruit tissues.
Silencing either gene did not alter total anthocyanin levels but completely abolished acylated anthocyanin accumulation, indicating that both enzymes are required for the modification process.
This result confirms their core regulatory role in pigment acylation and suggests evolutionary diversification of BAHD acyltransferases into anthocyanin-modifying functions.
“Our findings not only pinpoint the genes responsible for anthocyanin acylation, but also establish a rapid functional validation pipeline in blueberry,” the research team said.
“The ability to precisely link metabolic profiles to genetic determinants opens new doors for breeding strategies aimed at improving fruit quality, nutritional functionality and stability of natural colourants."
"This represents a significant advance in understanding how bioactive compounds are shaped at the genetic level.”
The identification of VcBAHD-AT1 and VcBAHD-AT4 enables the development of molecular markers to select for cultivars enriched in acylated anthocyanins, potentially leading to blueberries with improved health-promoting properties.
Given the enhanced stability and possible improved bioavailability of acylated anthocyanins, these genetic insights also offer opportunities for natural pigment applications in food manufacturing, where colour durability is essential.
In addition, the optimised VIGS workflow can accelerate functional genomics studies targeting other fruit quality traits, supporting faster breeding cycles and innovation in berry improvement programmes.