Bered et al. 2015 (Conference Paper) Aechmea

Genetic structure in Aechmea calyculata explained by different type of vegetations in southern Atlantic Forest

Author(s):—Fernanda Bered, Clarisse Palma-Silva, Camila Zanella, Felipe Pinheiro, Miriam Büttow & Márcia Goetze 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 calyculata occurs in the southern region of the Atlantic Rainforest and presents a geographical distribution different from the remaining species of Aechmea subgenus Ortgiesia. While most species of Ortgiesia are found in the coastal line and nearby mountains in the eastern region of Brazil, A. calyculatadistribution extends from the mountain regions in eastern Brazil to northeastern Argentina, characterizing an east-to-west pattern of occurrence. The objectives of the present study were to investigate if there is an east-west genetic structure among A. calyculata populations, and to evaluate how the genetic diversity is distributed along the geographical range of the species. For this purpose, we sampled six populations of A. calyculata, totaling 144 individuals, which were genotyped using12 nuclear microsatellite markers (SSR). Added to this, two chloroplast regions (rpl32-trnL and rps16-trnK - cpDNA), and the nuclear gene phyC were sequenced for 43 and 40 individuals, respectively. Our results showed high levels of genetic structure across A. calyculata populations with a FST of 0.231 for SSR, a GST = 0.866 for cpDNA and of 0.486 for phyC. Structure analysis with SSR revealed a K = 2 genetic groups, with populations from the western region of distribution strongly differentiated from those of the east, with few individuals identified as migrants. The same pattern was recovered in BAPS analyses using cpDNA and phyC data. High levels of genetic diversity were found in A. calyculata for SSR, with the number of alleles ranging from 42 to 80, and the allelicrichness from 3.25 to 4.23 per population. Observed heterozygosity ranged from 0.389 to 0.638, while HE varied from 0.504 to 0.623. For cpDNA only five haplotypes were found for A. calyculata, varying from one to two per population. On the other hand, more variation was observed with phyC, which displayed nine haplotypes, varying from one to five per population. The present study revealed high genetic structure across the A. calyculata distribution, especially between populations of western and eastern regions of occurrence. These two regions are separated by Araucaria forest, and in higher altitudes by grassland (?Campos?), which could be acting as a barrier to gene flow between populations from the east and west. Nowadays grassland is restricted to higher altitudes but during the Pleistocene this was the predominant type of vegetation covering the southern region of Brazil, and could have promoted isolation. The genetic diversity indices found for A. calyculata were very similar among populations with SSR and cpDNA data. However, higher diversity was found for the eastern populations with phyC, which could indicate a long-term persistence of A. calyculata
in this region.

Keywords:—Phylogeography; Bromelioideae; Genetic Diversity.