Comparison of transcriptional profiles of flavonoid genes and anthocyanin contents during fruit development of two botanical forms of Fragaria chiloensis ssp. chiloensis

Abstract

Difference in fruit pigmentation observed between two botanical forms of Fragaria chiloensis ssp. chiloensis (form chiloensis and form patagonica) was studied through transcriptional and chemical approaches. The proportion of different anthocyanins was demonstrated to be characteristic of each botanical form, with pelargonidin 3-glucoside being the most abundant in f. patagonica fruit and cyaniding 3-glucoside as the major one in f. chiloensis fruit. Partial gene sequences of the phenylpropanoid and flavonoid biosynthesis pathways were isolated from the native Chilean strawberry fruits, and used to design gene-specific primers in order to perform transcriptional analyses by qRT-PCR. These genes showed spatial, developmental, and genotypic associated patterns. The red fruit of f. patagonica exhibited higher transcript levels of anthocyanin-related genes and higher levels of anthocyanins compared to the barely pigmented fruit of f. chiloensis. The anthocyanin accumulation in F. chiloensis ssp. chiloensis fruits was concomitant with the particular progress of the transcriptional activity of genes involved in the biosynthesis of flavonoid pigments. The differences in anthocyanin contents, both in terms of type and quantity, between the two botanical forms of F. chiloensis ssp. chiloensis were coincident with the differential transcriptional patterns found in the anthocyanin-related genes.