A Comarative phylogenic analysis of selected species of exacum of Sri Lanka with Osbeckia Octandra
Loading...
Date
2013
Authors
Maheswaran, S.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya
Abstract
The Exacums are members of the family Gentianaceae. These annual species are grown as flowering pot plants in the Western hemisphere for its beautiful and profuse blue or white flowers . There are eight Exacum species found wild in Sri Lanka: Exacum axillare, Exacum macranthum , Exacum pallidum, Exacum trinervium, Exacum walkerii, Exacum pedunculatum, Exacum petiolare and Exacum sessile of which four .are designated as threatened species. This study was conducted to determine the phylogenetic relationships of four of the endemic Sri Lankan Exacum species, E. trinervium; E. macranthum, E. walkerii and E. pedunculatum which show the potential for application in the floricultural industry with the non-endemic, commercial species E. affine, to compare their sequences of the Internal Transcribed Spacer (ITS) region of l8S-26S rDNA for use as a possible DNA typing target and to compare the Exacums of Sri Lanka with the morphologically similar species Osbeckia octandra.
DNA was isolated from younger leaves of the plants ; the ITS region was amplified by Polymerase Chain Reaction (PCR), and the nucleotide sequences of the PCR products were determined. The amplified products of the ITS region of different species were estimated to be 554-720 bp. Multiple sequence alignment of the ITS sequences were carried out using ClustalW program and phylogenetic relationship of the species was determined by using Mega 4.0.2 package . The two endemic species E. macranthum and E. trinervium clustered together in the phylogenetic tree while E. walkerii and E. pedunculatum formed a separate cluster ..The exotic species E. affine diverged from the cluster and branched separately. Osbeckia octandra did separate from all Exacum species.
Description
Keywords
Exacums , Gentianaceae , Osbeckia octandra , Phylogenic analysis