Molecular phylogeny of tribe Dipterocarpeae (family Dipterocarpaceae) based on sequence data of chloroplast and nuclear DNA.

Dipterocarpaceae is the most important tree family in the flora of Southeast Asia. Southeast Asian dipterocarps belong to subfamily Dipterocarpoideae and are divided into two tribes (Shoreae and Dipterocarpeae). The tribe Dipterocarpeae has eight genera including Anisoptera, Cotylelobium, Dipterocarpus, Stemonoporus, Upuna, Vateria, Vateriopsis and Vatica. Many studies have been carried out to resolve the taxonomic relationships of subfamily Dipterocarpoideae based on chloroplast and nuclear DNA. Almost all of them focused on the resolution of intra- and interspecific relationships within tribe Shoreae and genus Shorea while information on the fine scale phylogenetic structure of tribe Dipterocarpeae is rare. The aim of our study are to (1) construct phylogenetic relationships among the genera and species of tribe Dipterocarpeae using non-coding regions of the chloroplast and nuclear genomes; (2) test the utility of these sequences for phylogenetic construction of interspecific relationships.

Dipterocarp species from Vietnam, Indonesia, Philippines and Malaysia were sampled in the field and available at Institute of Forest Genetic and Forest Tree Breeding. A total of 55 samples belonging to 48 taxa and 8 genera of family Dipterocarpaceae were investigated including of genus Dipterocarpus, Vatica, Anisoptera, Cotylelobium, Upuna, Dryobalanops, Shorea, and Monotes as outgroup taxon.

Total genomic DNA was extracted from dried leaf tissue using as DNeasy® 96 Plant Kit (Cat. No. 69181; Qiagen, Hilden) following the manufacturer’s protocol. All regions were amplified by the polymerase chain reaction (PCR) using universal primers. The primers for trnL intron and trnL-trnF intergenic spacer regions were described in Taberlet et al. (1991), the primers for the petD region in Löhne and Borsch (2005) and the primers for the ITS region in Blattner (1999). The sequence data were obtained through direct sequencing of PCR products. The sequencing reactions were performed by using ABI Prism™ Big Dye™ Terminator Cycle Sequencing Ready Reaction Kit v1.1 (Applied Biosystems). The data were collected from capillary electrophoresis on the ABI Prism 3100® Genetic Analyzer with the Sequence Analysis Software v3.1 (Applied Biosystems).

Sequencing was performed with both the forward and reverse primers. The sequences of both strands were obtained and matched together to get exact sequences by using Staden Package (Staden et al 1998). For multiple alignment, the BioEdit Sequence Alignment Editor version 7.0.5.3 (Hall 1999) was used and the phylogenetic analysis was carried out with PAUP* v4.0b10 (Swofford 1998).

Supervisor: Prof. Dr. Reiner FINKELDEY (Forest Genetics and Forest Tree Breeding, Büsgen Insitute, Göttingen University).