Phylogeographic patterns of Calophyllum Braziliense Camb. (Calophyllaceae)based on the psbA-trnH cpDNA locus

Abstract

Background Past climate changes have severely influenced the current distribution of species and their genetic diversity. Phylogeography is the study of the principles and processes governing the geographic distributions of genealogical lineages [1]. South America has the world’s largest area of swamps, floodplains and wetlands in general [2]. Brazil’s major wetlands cover 2% of the country’s huge territory [3]. However, from a plant ecology standpoint, Brazilian freshwater wetlands are largely unknown and the scarce data available refer mostly to flooded forests of the Amazon [4]. Calophyllum Braziliense Camb. (Calophyllaceae), also know as guanandi, jacareuba or landim, is a canopy tree species typical of waterlogged areas from South and Central America. This species occurs in the humid tropical forests of Central America, Amazon Forests, Atlantic Forest (including restingas); and in the riverines forests of the Cerrado biome (brazilian savannah) [5,6]. However, unlike other species typical of flooded areas, C. Braziliense shows none of the morphological features common to flood-adapted plants. Calophyllum Braziliense is a hermaphroditic tree pollinated by bees. Its seeds are animal (mainly by bats) or water dispersed. The timber has excellent characteristics and is widely used. Calophyllum. Braziliense is also used in vegetation restoration programs and its leaves extract presents antiinflammatory activity [7]. This study examines the phylogeographic patterns of C. Braziliense based on the cpDNA intergenic region psbA-trnH. Methods Twenty four populations of C. Braziliense were sampled from Costa Rica (10° 12’N, 83° 47’W) to the Parana State in Brazil (25° 34’S, 48° 27’W). Samples were collected from about 5-10 adult trees in each population, totaling 192 individuals. Total DNA was extracted from leaves or cambium using the CTAB procedure described by Doyle & Doyle [8]. After a screening for cpDNA amplification and polymorphism in C. Braziliense, the psbA-trnH intergenic regions was selected [9]. Sequences were aligned using CLUSTAL-W implemented in the MEGA 4 software. The cpDNA haplotypes were defined by analyzing the sequences with DNASP 4.01. The genetic diversity indexes were estimated in ARLEQUIN 3.01. The phylogenetic relationships among the haplotypes were estimated using the median-joining algorithm implemented in NETWORK 4.1. An analysis of molecular variance (AMOVA) was performed in ARLEQUIN. A spatial analysis of molecular variance (SAMOVA) was conduced using the SAMOVA 1.0 software. To evaluate the hypothesis of population expansion, neutrality tests were computed in DNASP and ARLEQUIN.