In silico identification of three putative SWEET genes in Metroxylon sagu
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Date
2020
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IAARD Press
Abstract
Recent studies have identified Sugars Will Eventually be Exported Transporters (SWEET), a novel type of sugar transporters in diverse plant species. This gene family selectively transports different kinds of sugar substrates, including sucrose, fructose and glucose. In this paper, three Metroxylon sagu SWEET genes (MsSWEET-X, MsSWEET-Y and MsSWEET-Z), predicted to be involved in starch accumulation, were identified from the NCBI EST database. A comparative analysis was carried out against Arabidopsis thaliana TAIR and
Elaeis guineensis NCBI genome databases resulting in amino acid residues similarity of three MsSWEET genes of 21.32 to 76.25 %. One full-length coding sequence (CDS) of 229 amino acids from MsSWEET-X has been annotated as opposed to the partial CDSs from the other two. Three types of putative protein domains (Calreticulin, Glycosyl hydrolases and Triosephosphate transporter) were predicted for MsSWEET-X, MsSWEET-Y and MsSWEET-Z, respectively. Multiple Alignment sing Fast Fourier Transform (MAFFT) has identified three conserved amino acid motifs (Motif-A, Motif-B and Motif-C) among three compared species.
Phylogenetic analysis using Maximum-Likelihood Estimation has revealed two genes AtCRT3 and MsSWEET-X at the upstream of initial tree branches (0.17 and 0.12 length) showing their early evolutionary orthology. By contrast, MsSWEET-Y gene was predicted to be the latest homolog of SWEET16 and SWEET17 undergoing speciation events from both Arabidopsis and oil palm. Taken together, these results showed that even though the oil palm and sago palm shared the common ancestry of monocotyledonous family, their SWEET genes were divergent. The gene MsSWEET-X was highly close to its homolog in Arabidopsis.
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in silico, MAFFT, maximum-likelihood estimation, Metroxylon sagu, phylogenetic analysis, SWEET.