Molecular Characterisation of Gamma Tocopherol Methyl Transferase (γ-tmt) From Tomato CV Memory 1

The aim of this research was the cloning and sequencing of gamma tocopherol methyl transferase gene (γ-tmt) from Memory 1 cv and transferring it into an oilseed plant such as canola, in the future studies for improving its nutritional value.

Total RNA was extracted from tomato fruit and cDNA constructed. By using specific primers the γ-tmt gene was amplified by PCR reaction and a 1089 bp fragment was produced. The amplified fragment and the pBluescript (SK-) vector were digested by XbaI. The ligation reaction was carried out by T4 ligase. E. coli competent cells were transformed by the resulting vector and recombinant colonies were identified using the white-blue screening assay.

The nucleotide sequence of the gene was determined and aligned with the available sequences recorded in the NCBI data bank. This sequence showed 98% similarity with the other recorded γ-tmts from Solanaceae family. Some changes in nucleotide sequence and the deduced amino acids were observed. The secondary and tertiary structures of the protein were predicted, using PSIpred software. A phylogenetic tree was also constructed for the protein product of the gene, using ClustalW.

The cloned cDNA of γ-tmt showed 98 % similarity with the recorded sequence from tomato cv Cerasiforme. Upon transfer of this gene into an oil seed plant such as canola, one can increase both its nutritional value and resistance to environmental stresses.