Contribution to the knowledge of genome size evolution in edible blueberries (genus Vaccinium)

Abstract

BACKGROUND: Vaccinium is one of the largest genera (ca. 500 species) of Ericaceae, well known for its edible and ornamental uses. Although there is certain karyological knowledge, information about genome size (GS) is scarce in the genus. OBJECTIVE: The main goal is providing GS data for several Vaccinium species with prevalence in Europe and Western Asia and analysing global GS variation in the genus, considering available data and phylogenetic context. METHODS: New GS assessments were obtained by flow cytometry and chromosome counts were verified. Phylogenetic analyses (using nuclear ITS, and chloroplastic matK and ndhF) were performed by Bayesian inference and reconstruction of ancestral GS by maximum parsimony. RESULTS: We obtained GS data for five Vaccinium species (13 populations). Three species are reported for the first time. Values (2C) ranged between 1.16-1.47 pg at the diploid (2n = 24) and between 3.13-3.16 pg at the tetraploid (2n = 48) levels. The five species here investigated have been placed and analysed in a reconstructed phylogenetic background (including 68 taxa). CONCLUSIONS: GS values of Vaccinium can be considered "very small". The preliminary reconstruction of ancestral GS would point to a reduction in Vaccinium, although more data is needed to establish global GS evolutionary trend in the genus.