Khairul Azmi Rahman
Research Abstract / Synopsis
Title: Phylogenetic Relationships and DNA Sequence-Based Identification of Shorea species (Dipterocarpaceae) using Floral Organ Identity and Chloroplast Genes
Dipterocarpaceae is a dominant plant family and serves as an ecologically and economically important group of tree species in tropical rainforests. They occupy the canopy layer and, together with other organisms, form a diverse and complex ecosystem. Economically, the species of this family were marketed as hardwood for building materials and furniture. They were also used for their resins, nuts, and tannins.
Research into species relationships between Shorea species and their closely related species has been a topic of interest for several years. Understanding their interrelationships is not only important for plant systematics, but also for sustainable forest management. However, this topic requires further investigation in order to provide sound information on the ongoing discussion about the systematic classification of the genus Shorea. We will use DNA barcoding and phylogenetic approaches in the species identification process. In this phylogenetic study, floral organ identity and chloroplast genes are used. The knowledge of flower evolution, for example the conversion of the apical meristem of the shoot from leaf production to flower production in plants, were not fully exploited in the phylogenetic studies. LEAFY (abbreviated LFY) is the specific gene responsible for the conversion. This approach could be useful to further elucidate the phylogenetic position of this genus and to resolve species relationships. Genetic diversity is examined using sequences of single-copy genes of floral organ identity and chloroplast barcoding sequences to obtain additional information on the evolutionary history of the species.
The resolution of the chloroplast DNA (cpDNA) regions was too low to identify all samples at the species level. Therefore, in addition to cpDNA markers, we will also use new nuclear DNA (nDNA) regions from floral organ identity genes for phylogenetic analyses. The use of these floral organ identity genes will be useful in constructing the evolutionary patterns of flower traits in dipterocarps. These genes play an important role in the flowering period and timing of each Shorea species.
The main aim of this research work is to provide a comprehensive assessment of the phylogenetic relationships and biogeographical information between Shorea species from Indonesia and Malaysia based on floral organ identity and chloroplast genes. A secondary goal of this work is the development of an identification tool for Shorea species through a molecular genetic approach. This study would facilitate comparisons between traditional and molecular taxonomical identification.