Schutz 2015 (Conference Paper) Deuterocohnia

Chloroplast haplotypes indicate ancient and recent hybridization in the genus Deuterocohnia (Bromeliaceae)

Author(s):—Nicole Schütz & Georg Zizka in Benko-Iseppon, A.M.; Alves, M. & Louzada, R. (2015) An overview and abstracts of the First World Congress on Bromeliaceae Evolution. Rodriguésia 66(2): A1-A66.

Publication:— (2015).

Abstract:—The genus Deuterocohnia Mez (Pitcairnioideae s.str.) comprises 17 species with a distribution centre in theAndes of southern Bolivia and northern Argentina. The plants grow as terrestrials on dry, rocky slopes or barerocks. Succulent leaves and CAM photosynthesis are some of the adaptations related to their xerothermic habitat. Our ongoing project involves analyses of chloroplast haplotypes (trnS-ycf3, rps16-trnK, rpl32-trnL) fromall Deuterocohnia species. The chloroplast haplotypes are not species-specific in Deuterocohnia. Thus, onehaplotype was sometimes shared by several species, where the same species may harbour different haplotypes.The arrangement of haplotypes followed geographical patterns rather than taxonomic boundaries, which mayindicate some residual gene flow among populations from different Deuterocohnia species. Phenotypic speciescoherence in the background of ongoing gene flow may then be maintained by sets of co-adapted alleles, as wassuggested by the porous genome concept (Wu 2001, Palma-Silva et al. 2011). As variation among the sequences of Deuterocohnia was low, we could include samples of the closely related genera Dyckia and Encholirium into a haplotype network. While the two major subgroups of Deuterocohnia were separated by 32 mutational steps, one of the two subgroups was connected by only 11/18 mutational steps to Encholirium/Dyckia. If we further include Fosterella into the network, Deuterocohnia proved to be deeply paraphyletic, with five species forming a sister group to the closely related genera Encholirium/Dyckia. Considering that morphology as well as nuclear DNAdata generated in the present study and in a former AFLP analysis (Horres 2003) all corroborate the monophylyof Deuterocohnia, the apparent paraphyly displayed in cpDNA analyses is interpreted to be the consequence ofa chloroplast capture event. This involves the introgression of the chloroplast genome from the common ancestorof the Dyckia/Encholirium lineage into the ancestor of one Deuterocohnia subclade.

Keywords:—Deuterocohnia; Chloroplast Haplotypes; Hybridization.