Poster: Bioinformatics

Abs # 908: Functional prediction of a T-DNA tagged gene of Arabidopsis thaliana by in silico analysis

Presenter:	Mandal, Abul , abul.mandal@inv.his.se
Authors	Mandal, Abul  (A)   Svensson, Maria  (A)   Lundh, Dan  (C)   Bergman, Per  (B)
Affiliations:	(A): University of Skovde, Department of Natural Sciences (B): Swedish University of Agricultural Sciences, Department of Plant Biology (C): University of Skovde, Department of Computer Sciences
Web Site:	http://www.his.se

We have employed a gene knockout approach using T-DNA tagging and in vivo gene fusion in Arabidopsis thaliana for identification and isolation of specific plant genes. Screening of about 3000 T-DNA tagged lines resulted in identification of a mutant line (no. 197) that exhibits a significant delay in stem elongation and flowering time. From this line a 600 bp of plant genomic DNA fragment downstream of the left T-DNA-plant DNA junction was cloned by inverse PCR. BLAST searching in the A. thaliana genomic database indicated a putative gene, frf (flowering regulating factor), with unknown function downstream of the T-DNA insert. Bioinformatic tools were used for prediction of possible protein structure and function. The protein structure predicted by fold recognition contains a binding site for valeric acid. The chemical composition of valeric acid is very similar to that of mevalonic acid, which participates in gibberellin biosynthesis. Furthermore, when analyzed by comparing the pattern of substrate binding in the PDB files these two acids also show a high similarity in the atomic structure of their binding sites. Mevalonic acid participates in the production of isopentenyl diphosphate which, in higher plants, is involved in terpenoid biosynthesis. The terpenoid family includes, among others, the plant growth hormones like gibberellins. Thus, the results we obtained in silico suggest that the gene we identified by T-DNA tagging might be involved in regulating gibberellin biosynthesis in A. thaliana. To investigate this hypothesis, whether FRF is indeed involved in GA-response in A. thaliana we sprayed the plants of line no. 197 with gibberellic acid (GA3). This treatment resulted in an earlier onset of flowering, almost similar to that in wild type plants.