Mitochondrial genome of Sargassum thunbergii: conservation and variability of mitogenomes within the subgenus Bactrophycus

Abstract

Sargassum thunbergii (Mertens ex Roth) Kuntze is a common brown seaweed in rocky intertidal zones along the northwestern Pacific coast. In the present study, we sequenced and annotated the complete mitochondrial genome of S. thunbergii. The circular S. thunbergii mitogenome is 34,748 bp in size and contains the same set of 65 genes as other mtDNAs in four Sargassum species. The genome organization including the gene order, overlapping regions between genes and the total length of inter-genic regions is highly similar to the other Bactrophycus species. The comparison by genome scale alignment displays only minor differences in gene lengths, but higher divergence in inter-genic spacer regions, especially the cox3-atp6 inter-genic spacer. Mitochondrial phylogenomics suggests that S. thunbergii is tightly combined with Sargassum muticum and Sargassum hemiphyllum forming the sect. Teretia clade with strong support values (NJ/ML, 100%). The present data illustrate that the complete mtDNAs could provide a more complete assessment of their phylogenetic relationships.

• Bactrophycus
• brown seaweed
• mitochondrial genome
• mitogenome
• Sargassum thunbergii

Declaration of interest

Completion of this piece of work is based on the seaweed culture collection center, Chinese Academy of Sciences (www.caslivealgae.com). Financial support was received from the 863 Hi-Tech Research and Development Program of China (No. 2012AA10A413), the National Natural Science Foundation of China (No. 41206146), the Scientific Research Foundation for Outstanding Young Scientists of Shandong Province (No. BS2013HZ004), the Special Fund of the membership of Youth Innovation Promotion Association, Chinese Academy of Sciences (CAS), the Open-end Funds of Jiangsu Key Laboratory of Marine Biotechnology, Huaihai Institute of Technology (No. 2014HS002), and the Open Research Fund of Key Laboratory of East China Sea and Oceanic Fishery Resources Exploitation and Utilization, Ministry of Agriculture (No. K201311). The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

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