Abstract
Anthocyanins are natural health promoting pigments that can be produced in large quantities in some purple carrot cultivars. Decoration patterns of anthocyanins, such as acylation, can greatly influence their stability and biological properties and use in the food industry as nutraceuticals and natural colorants. Despite recent advances made toward understanding the genetic control of anthocyanin accumulation in purple carrot, the genetic mechanism controlling acylation of anthocyanin in carrot root have not been studied yet. In the present study, we performed fine mapping combined with gene expression analyses (RNA-Seq and RT-qPCR) to identify the genetic factor conditioning the accumulation of non-acylated (Cy3XGG) versus acylated (Cy3XFGG and Cy3XSGG) cyanidin derivatives, in three carrot populations. Segregation and mapping analysis pointed to a single gene with dominant effect controlling anthocyanin acylation in the root, located in a 576kb region containing 29 predicted genes. Orthologous and phylogenetic analyses enabled the identification of a cluster of three SCPL-acyltransferases coding genes within this region. Comparative transcriptome analysis indicated that only one of these three genes, DcSCPL1, was always expressed in association with anthocyanin pigmentation in the root and was co-expressed with DcMYB7, a gene known to activate anthocyanin biosynthetic genes in carrot. DcSCPL1 sequence analysis, in root tissue containing a low level of acylated anthocyanins, demonstrated the presence of an insertion causing an abnormal splicing of the 3rd exon during mRNA editing, likely resulting in the production of a non-functional acyltransferase and explaining the reduced acylation phenotype. This study provides strong linkage-mapping and functional evidences for the candidacy of DcSCPL1 as a primary regulator of anthocyanin acylation in carrot storage root.
Highlights
Anthocyanins are water-soluble pigments responsible for the vibrant red-to-blue color commonly found in many organs of higher plant species, including flowers and fruits, which contribute to attract animals and insects for seed dispersal and pollination (Koes et al, 2005)
The populations used by Bannoud et al (2019) did not segregate for the Root Anthocyanin Acylation 1 (Raa1) locus and accumulated large amount of acylated anthocyanin which resembles the high acylated anthocyanins (HAA) phenotype described in the present study
Allele-phenotype interaction analysis indicated that the gene controlling the Raa1 locus has a dominant effect, with HAA being dominant over low acylated anthocyanin” (LAA)
Summary
Anthocyanins are water-soluble pigments responsible for the vibrant red-to-blue color commonly found in many organs of higher plant species, including flowers and fruits, which contribute to attract animals and insects for seed dispersal and pollination (Koes et al, 2005). Anthocyanins are used as natural colorants in the food industry, and the potential health benefits associated with their antioxidant and anti-inflammatory properties has brought them additional attention (Giusti and Wrolstad, 2003; Akhtar et al, 2017). Anthocyanins are produced through the flavonoid pathway and stored in the vacuole (Koes et al, 2005). Their core structure is composed of an aglycone backbone (C6-C3-C6) known as anthocyanidins, with cyanidin, delphinidin, pelargonidin, peonidin, petunidin, and malvidin being the anthocyanidins most commonly found in nature (Ramos et al, 2014). Various patterns of glycosylation and acylation of the aglycone backbone can affect the chemical properties of anthocyanins, including cellular transport, stability, and bioavailability (Prior and Wu, 2006). The relative content of acylated and non-acylated anthocyanin forms directs their utilization in the food industry as nutraceuticals and natural colorants
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
