Abstract
The Chlorella sp. Dachan belongs to the genus Chlorella. Chlorella sp is widely distributed in the fresh water area with the largest number of species. It is easy to cultivate and propagate and it can use photosynthesis with high application value. In this study, the complete nucleotide sequence of the circular mitochondrial (mt) DNA of the chlorophyte alga C. sp. Dachan has been determined (55,450 base-pairs, A + T content 71.69%). The genes identified encode three subunits of the cytochome oxidase, apocytochrome b, seven subunits of the NADH dehydrogenase complex (nad1 3 4 5 7 9 and 4 L), three ATPase subunits (atp1, atp6, atp9), two ribosomal RNAs small subunit (srn) and large subunit (lrn) RNA), 27 tRNAs, 2 ribosome proteins. The complete mitochondrial genome sequence will provide new molecular biology information to further understand the genetic diversity of the Chlorella sp. Dachan and to protect this population.
The Chlorella sp. Dachan belongs to the genus Chlorella within the family Chlorellaceae. Researchers had reported three newly sequenced and assembled genomes of Chlorella, including Chlorella sorokiniana BD09, Chlorella sorokiniana BD08, and Chlorlella sp. Dachan, all of which are widely used in piggery industry for nutrient removal from the wastewater (Ahn et al. Citation2012) However, mitochondrial molecular studies about C. sp. Dachan that are limited. Here, we assembled and characterized the complete mitochondrial genome of C. sp. Dachan.
The total genomic DNA was extracted from China: Taiwan (E119°18′03, S20°45′25) and the whole-genome library of genomic DNA was sequenced using the Illumina Hiseq2500 platform. The information of sample of C. sp. Dachan was stored in NCBI (Accession No. SRR8163070). The sequencing reads were trimmed using Trimmomatic v0.36 (Bolger et al. Citation2014) and assembled with Mira v4.0.2 and MITObim v1.8 software (Hahn et al. Citation2013), then the 43 genes present in the genome were annotated using Mitofy (https://vcru.wisc.edu/cgi-bin/mitofy/mitofy.cgi) (Alverson et al. Citation2010).
The complete mitochondrial genome of C. sp. Dachan is a double-stranded, circular DNA 55,450 bp in total length (GenBank Accession No. MT084797). The complete mitochondrial genome of C. sp. Dachan has a length of 55,450 bp with a typical circle structure that contains 27 tRNA genes, 16 protein-coding genes, and 2 rRNA genes, GC content is 28.31%.
The phylogenetic analysis of 9 mitochondrial genomes using MEGA 7(Kumar et al. Citation2016), C. sp. Dachan and Chlorella sorokiniana 1230 are the most closely related species (). The mitogenome of C. sp. Dachan would contribute to the understanding of the phylogeny and evolution of Chlorellaceae.
Figure 1. Neighbor-joining molecular phylogenetic tree of 9 species of Chlorellaceae based on complete mitogenome sequences, the pentagram is the species of this study. GenBank accession numbers are indicated in brackets.
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No potential conflict of interest was reported by the author(s).
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References
- Ahn J-W, Hwangbo K, Lee SY, Choi H-G, Park Y-I, Liu JR, Jeong W-J. 2012. A new arctic chlorella species for biodiesel production. Bioresour Technol. 125:340–343.
- Alverson AJ, Wei X, Rice DW, Stern DB, Barry K, Palmer JD. 2010. Insights into the evolution of mitochondrial genome size from complete sequences of Citrullus lanatus and Cucurbita pepo (Cucurbitaceae). Mol Biol Evol. 27(6):1436.
- Bolger AM, Lohse M, Usadel B. 2014. Trimmomatic: a flexible trimmer for Illumina sequence data. Bioinformatics (Oxford, England). 30(15):2114–2120.
- Hahn C, Bachmann L, Chevreux B. 2013. Reconstructing mitochondrial genomes directly from genomic next-generation sequencing reads–a baiting and iterative mapping approach. Nucleic Acids Research. 41(13):e129–e129.
- Kumar S, Stecher G, Tamura K. 2016. Mega7: molecular evolutionary genetics analysis version 7.0 for bigger datasets. Mol Biol Evol. 33(7):1870–1874.