Full Length Research Paper

Analysis of expressed sequence tags derived from inflorescence shoot of Tectona grandis (teak)

H. Mohd Rosli¹*, N. M. Saleh², M. I. Mohd Noor³, M. Norwati¹, B. Norlia¹ and A. Norwati¹

¹Genetic Unit, Forest Research Institute Malaysia (FRIM), 52109 Kepong, Selangor, Malaysia.

²Cell and Molecular Biology Department, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.

³Malaysia Genome Institute, Helix Emas Block, UKM-MTDC Technology Centre, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.

*Corresponding author. E-mail: mrosli@frim.gov.my.

Abbreviations: ESTs, Expressed sequence tags; GO, gene ontology; TIS4, teak inflorescence shoot stage 4.

Accepted 21 September, 2009

   Abstract

Teak Inflorescence Shoot Stage 4 (TIS4) shoots bearing the floral meristems were used to construct a cDNA librariy with insert size range of 1500 - 5000 bp. The titer of the library was 7.5 x 10⁵ pfu/ml (primary) and 4.5 x 10⁹ pfu/ml (amplified). EST generation and analysis were performed using the cDNA library where a total of 1384 plaques were randomly picked and their inserts PCR-amplified using T3 and T7 universal primers. Only 1125 plaques generated single amplified fragments, each which were purified and sequenced using the SK universal primer. The generated raw 5’ ESTs were filtered and clustered. A total of 674 nonredundants (69 consensus sequences and 605 singletons) were generated and their identities searched through BLASTX. Of the 674 nonredundants, 107 of them (15.9%) showed no hits or no identity. All the 567 nonredundants identified through BLASTX were categorized into their functional categories and were further analysed using InterProScan to detect their protein signatures and to assign their GO numbers. From all the sequences analysed, only 186 (32.8%) sequences were given the GO numbers and grouped into the three GO main categories namely biological process, cellular component and molecular function. Several important ESTs were highlighted based on their functional categories.  There were five sequences found to be related to flowering and light induction.

Key words: ESTs, flowering, Tectona grandis.