Goetze et al. 2015 (Conference Paper) Aechmea, Ortgiesia

Diversification of Bromelioideae in the Atlantic rainforest: a case study of Aechmea subgenus Ortgiesia

Author(s):—M. Goetze, K. Schulte, C. Palma-Silva, C.M. Zanella, M.V. Büttow, F. Capra & F. Bered 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:—Aechmea subgenus Ortgiesia comprises ca. 17 species which occur in Brazil, Argentina, Paraguay, and Uruguay. In Brazil the species are found in the south and southeastern regions, with most of them endemic to the Brazilian Atlantic rainforest. Interspecific relationships in Aechmea subgenus Ortgiesia are so far unclear and the lack of a phylogenetic framework has hampered the evaluation of morphological characters and their taxonomic value. Therefore, the objectives of the study were to reconstruct interspecific relationships in Ortgiesia based on AFLP (Amplified Fragment Length Polymorphism) data; to examine the evolution of key morphological characters and discuss their taxonomic value; and to explore biogeographic patterns in Ortgiesia. A total of 96 accessions belonging to 14 species of Ortgiesia were sampled and genotyped with 11 AFLP primer combinations. Our results confirmed previous studies based on a smaller sampling that Aechmea subgenus Ortgiesia is a natural group. Two main groups were recovered in the neighbor joining (NJ) tree, one formed by all accessions of A. blumenavii and A. calyculata and the second encompassing the remaining 12 species. In the second group four main subgroups were recovered: 1) formed by A. gamosepala, A. gracilis,and A. recurvata; 2) united A. coelestis, A. organensis, and A. sp; 3) clustered A. comata, A. kertesziae, and A. kleinii; 4) mainly formed by A. caudata and A. winkleri. Mapping the petal color (yellow, blue, pink, orwhite), inflorescence type (simple or compound), and shape (ellipsoid, subcylindric, cylindric, or pyramidal) onto the NJ tree, revealed that yellow petals and simple inflorescences are the ancestral state in Ortgiesia. Compound inflorescences evolved at least three times independently, while high levels of homoplasy were observed for inflorescence shape. So, only petal color was confirmed as a valuable diagnostic character for Aechmea subgenus Ortgiesia. Biogeographic characterization indicated ombrophilous forest as the ancestral area for Ortgiesia. Most Ortgiesia occur between latitudes 25° and 27° S, in the southern region of the Brazilian Atlantic rainforest, which indicates this area as the center of diversity for the subgenus. In this study we presented the first insights into interspecific relationships in Aechmea subgenus Ortgiesia, revealingthe main groups and subgroups of species, which thus now could be the focus of population genetics and phylogeographic studies to further shed light on their relationships. Ancestral state reconstruction analysis revealed different levels of homoplasy of inflorescence branching pattern, a character that is normally used as diagnostic in Aechmea subgenus Ortgiesia. Petal color, another character used in species identification of Ortgiesia, was confirmed as valuable by our analysis. The biogeographic pattern of Ortgiesia indicates that the subgenus diversified at the southern portion of the Brazilian Atlantic rainforest and this process may have been affected by Pleistocene climatic oscillations, leading to geographical isolation and thus promoting allopatric speciation.

Keywords:—Interspecific Relationships; Aflp; Character Evolution.