Characterization of a type III polyketide synthase (sjPKS1) gene and its expression in response to light in the economic brown alga Saccharina japonica
Phlorotannins are among the most important defensive molecules in kelp. They have been majorly identified in brown algae so far. Type III polyketide synthase (PKS) is regarded as one of the enzymes catalyzing a major step in the biosynthetic pathway of phlorotannins. In this study, a type III PKS gene ( sjPKS1 ) is characterized from the economic brown alga Saccharina japonica sporophyte. It contains 7 exons and 6 introns. The sjPKS1 open reading frame consists of 1245 nucleotides encoding a protein of 414 amino acids. The sjPKS1 are 87%, 83%, and 82% identical to that of Ectocarpus siliculosus , Sargassum binderi , and Sargassum fusiforme at the nucleotide level, respectively. While the amino acid sequences of sjPKS1 share more than 90% identity to that of the three brown algae species. The sjPKS1 expression at 200 µmol photons m −2 s −1 was significantly higher than at 20 and 50 µmol photons m −2 s −1 in sporophytic seedlings, so did the content of soluble phlorotannins inside the plants. Seven motifs in response to light are identified in the 5′ flanking region of sjPKS1 and two potential transcription factors are predicted by screening yeast one-hybrid library.
危险品化学品经营许可证（带存储）