Phylogeny and evolution of flower color polymorphism in the subfamily Linoideae (Linaceae)

ID: 613 / 230

Category: Abstract

Track: Pending

Proposed Symposium Title: Phylogeny and evolution of flower color polymorphism in the subfamily Linoideae (Linaceae)

Authors:

Mireya Burgos-Hernández, Alejandra Villalvazo-Hernández

Affiliations: Department of Botany, Colegio de Postgraduados, Texcoco, Mexico.

Abstract:

Linoideae is one of the two known subfamilies in Linaceae and the larger of the two. The taxonomy of the subfamily at the intergeneric and sectional levels has been questioned over the years. Furthermore, knowledge of the evolution of floral characters is still incipient. In particular, the evolution of flower color is still uncertain, despite its ecological importance and being a conspicuous and variable trait in angiosperms. We evaluated the phylogenetic relationships of genera and sections using a Parsimony Analysis and Bayesian Inference, and the ancestral states of flower colors were reconstructed based on S-DIVA model on a phylogenetic tree with branch lengths proportional to time. Four of the five currently accepted sections were monophyletic (Cathartolinum, Dasylinum, Linum, and Syllinum). The results suggest reassessing the taxonomic status of the segregated genera and re-incorporating them into Linum. We propose to accept the Stellerolinon section and re-evaluate Linopsis, whose representatives were recovered in three separate clades. Our results show a close relationship between Linum bienne and L. villarianum with the cultivated flax, L. usitatissimum, with strong support. Knowing the phylogenetic relationships of this species is essential to explore the potential use of available resources from its sister species. The ancestral flower color of Linoideae was yellow-white. Purple and yellow-white colors were recovered in the deep nodes. Meanwhile, the colors pink, blue, and red were the most recent to appear. These results seem to be related to diversification events, biogeographic history, and ecological aspects of the subfamily. Our reconstruction constitutes the first scenario to explore the evolution of flower color, leading to new hypotheses for future research on flax.

: 181, 198, 91

Key words: evolution, flax lineages, molecular clock, taxonomy