Complete plastid genome of an ecologically important brown alga Sargassum thunbergii (Fucales, Phaeophyceae)

The brown algal species Sargassum thunbergii (Fucales, Phaeophyceae) is widely distributed in coastal area of East Asia. This alga is ecologically and economically important seaweeds; however, no genome data was reported thus far. To get a better understanding of organellar genome of S. thunbergii, we sequenced and annotated its complete plastid genome. The circular plastid genome is 124,592 bp in size with 30.4% GC content, which is composed of a large single-copy (LSC) region of 73,668 bp, a small single-copy (SSC) region of 40,032 bp, and two inverted repeat (IR) of 5446 bp each. The plastid genome of S. thunbergii includes 139 protein-coding genes, six ribosomal RNA (rRNA) operons, 28 transfer RNA (tRNA) sequences, and one intron (214 bp) in tRNA-Leu (trnL) gene. Five overlapping genes were identified in the compact plastid genome. Base on the comparison with previously published five brown algae plastid genomes, we found that the gene content and gene order of S. thunbergii are identical to that of other Fucales species Fucus vesiculosus.