Molecular cloning and sequence analysis of methionine adenosyltransferase from the economic seaweed Undaria pinnatifida

The methionine adenosyltransferase gene (MAT) had been isolated from an economic seaweed Undaria pinnatifida by PCR using degenerate primers. The cDNA was 1,491 bp in length with an open reading frame of 1,194 nucleotides, encoding a deduced protein of 397 amino acids. The protein had a predicted molecular weight of 43.2 kDa, and the isoelectric point was 5.244. The sequence contains a 92 bp 5′-untranslated region (UTR) and a 205 bp 3′-UTR. The methionine adenosyltransferase (MAT) sequence of U. pinnatifida (UpMAT) shared 68–92 % identities with the previous published MAT sequences of other species. Phylogenetic analysis indicated that the phylogenetic relationship of UpMAT with some other seaweeds was closer than with those of higher plants. Under different stress conditions, the relative mRNA expression levels of the MAT of U. pinnatifida (UpMAT) were measured by real-time quantitative PCR, and the results demonstrated that the UpMAT might help to protect the alga against various abiotic stresses.