Skip to main content
NCBI home page
Mitochondrial DNA. Part B, Resources logoLink to Mitochondrial DNA. Part B, Resources
. 2022 Feb 24;7(2):409–411. doi: 10.1080/23802359.2021.1875899

Mussel Unio douglasiae MG from the Chihe River: mitogenome description and phylogenetic analysis

Danni Li a,*, Pengjie Yang a,b,*, Yunjie Zhang a, Yueer Shen a, Yalin Zhang a, Qianxue Shao a, Pengyu Chen a, Shoubao Yang a,✉
PMCID: PMC8890566  PMID: 35252570

Abstract

The genus Unio is one of the widespread freshwater bivalves. To date, its intra-generic phylogeny remains controversial and therefore the mitochondrial genome data is needed. Here, we report the complete mitogenome of Unio douglasiae MG that is distributed in the Chihe River, a branch of Huaihe River, East China. This mitochondrial genome is 15,764 base pair in total length. It consists of 37 genes: 13 protein-coding genes, 22 tRNA genes, and 2 rRNA genes (12S and 16S). The base composition was 38.38% for A, 26.48% for T, 23.17% for C, and 11.98% for G, showing an obvious bias of higher A + T content (64.86%) than the G + C content (35.14%). Phylogenetic analysis showed that U. douglasiae MG is clustered with other Unio and Nodularia mollusks in the family Unionidae. These results showed that combine with morphological techniques, the mitogenome can provide useful information to further understanding of the genetics, systematics, and conservation of this endangered species.

Keywords: Unio douglasiae MG, mitochondrial genome, phylogenetic analysis

Unio douglasiae (Gray) belongs to the Eulamellibranchia, Unionodae, Unio. It distributed widely in China, Korean, Eastern Russia, and Japan (Cho et al. 1983; Takaki 1992; Graf and Cummings 2007; Li et al. 2013; Nam et al. 2015; Nishio et al. 2016). In China, U. douglasiae is a widespread freshwater mussel distributed from the Zhujiang River, Dongting Lake, Yangtze River to Songhua River (Liu et al. 2009; Xu et al. 2009; Chen et al. 2010; Xiong et al. 2010; Xue et al. 2019). In addition, as a benthic bivalve and filter-feeder (Chen et al. 2011; Kim et al. 2011; Xiao et al. 2012; Ouyang et al. 2013; Wang et al. 2013), it plays an important role in maintaining water ecosystem balance, and serving as a biological indicator for water quality (Yokoyama and Park 2003; Watanabe et al. 2006; Maoka et al. 2012; Kim et al. 2017; Wang 2017; Jiang et al. 2020). However, its wild population declines rapidly due to overfishing, water pollution, and destruction of habitats.

In this study, the U. douglasiae MG specimen was collected from the Chihe River, a branch of Huaihe River in Mingguang city, Anhui province of China (Latitude 32.789726 and longitude 117.969780), and has been deposited at the Aquatic Service Platform of Shaoxing city (Voucher no. SXAF20200710).

The complete mitogenome sequence of U. douglasiae MG is obtained by PCR amplification and Sanger sequencing using an ABI3730 sequencer (Applied Biosystems, USA). It’s 15,764 bp in total length (GenBank accession no. MT764726), including 37 genes: 13 protein-coding genes, 22 tRNA genes, and 2 rRNA genes (12S and 16S). The base composition was 38.38% for A, 26.48% for T, 23.17% for C, and 11.98% for G, showing an obvious bias of higher A + T content (64.86%) than the G + C content (35.14%).

Similar to other mollusks, two tRNA genes (tRNAAsp, and tRNAHis) and nine protein-coding genes (COXI, COXII, COXIII, ND3, ND4, ND4L, ND5, ATP6, and ATP8) are encoded on the light strand (L-strand). Typical ‘ATG’ is used as the initiator codon in eight protein-coding genes (COXII, COXIII, ND2, ND3, ND4, ND4L, ND6, and ATP6). ‘TAA’ is used as the terminator codon in eight protein-coding genes (COXII, COXIII, ND2, ND3, ND5, ND6, ATP6, and Cytb), and ‘TAG’ is used in five protein-coding genes (COXI, ND1, ND4, ND4L, and ATP8).

The total length of two rRNA genes (12S and 16S) is 2152 bp, and they are separated by three tRNA genes including tRNALys, tRNAThr, and tRNATyr, which is identical to the rRNA gene arrangement of other mussels (Breton et al. 2011; Wang et al. 2016a, 2016b).

Twenty-six complete mitogenome sequences were used for phylogenetic tree construction by the neighbor-joining method (Figure 1). The results showed that U. douglasiae MG is clustered with other Unio and Nodularia mollusks in the family Unionidae. The present study shows that, combine with morphological techniques (Wei et al. 1994; Wu et al. 1999), the mitogenome can provide useful information to further understanding of the genetics, systematics, and conservation of this endangered species.

Figure 1.

Figure 1.

Open in a new tab

The phylogenetic analysis of Unio douglasiae MG and other mollusks based on the mitogenome sequences.

Funding Statement

This work was supported by the Public Welfare Project of Shaoxing City [2018C20012], the Young & Middle-aged Academic Backbone Project of Shaoxing University [2014], the National University Student Innovation and Entrepreneurship Project [202010349001], and the Key Cultivation Project of 2021 Challenge Cup of Shaoxing University [2020].

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are freely available at NCBI GenBank database (https://www.ncbi.nlm.nih.gov) with a accession no. MT764726. And the data that support the findings of this study are also available from the corresponding author, Dr. Yang, upon reasonable request.

References

  1. Breton S, Stewart DT, Shepardson S, Trdan RJ, Bogan AE, Chapman EG, Ruminas AJ, Piontkivska H, Hoeh WR.. 2011. Novel protein genes in animal mtDNA: a new sex determination system in freshwater mussels (Bivalvia: Unionoida)? Mol Biol Evol. 28(5):1645–1659. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Chen TH, Ouyang S, Xiong LF, Qi T, Wu XP.. 2010. Study on the population structure and reproductive traits of Unio douglasiae in Qinglan Lake, Jiangxi province. Acta Hydrobiol Sin. 36(3):473–480. [Google Scholar]
  3. Chen B, Yin DG, Yuan Q, Luo J, Fan JH.. 2011. Mechanisms of high rigidity and high strength of Unio Douglasiae shell. Rare Metal Mater Eng. 40(S1):69–72. [Google Scholar]
  4. Cho HC, Chung PR, Lee KT.. 1983. Distribution of medically important freshwater snails And larval trematodes from Parafossarulus manchouricus and Semisulcospira libertina around the Jinyang Lake in Kyongsang-Nam-Do, Korea . Kisaengchunghak Chapchi. 21(2):193–204. [DOI] [PubMed] [Google Scholar]
  5. Graf DL, Cummings KS.. 2007. Review of the systematics and global diversity of freshwater mussel species (bivalvia: Unionoida). J Molluscan Stud. 73(4):291–314. [Google Scholar]
  6. Jiang WQ, Liu SL, Jian MF, Hu QW.. 2020. Deposition characteristics of microplastics in benthic animals from the main estuaries of Poyang Lake. Chin J Ecol. 39(04):1273–1280. [Google Scholar]
  7. Kim MS, Lee YJ, Ha SY, Kim BH, Hwang SJ, Kwon JT, Choi JW, Shin KH.. 2017. Accumulation of microcystin (LR, RR and YR) in three freshwater bivalves in Microcystis aeruginosa bloom using dual isotope tracer. Mar Drugs. 15(7):226–241. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Kim BH, Lee JH, Hwang SJ.. 2011. Inter- and intra-specific differences in filtering activities between two unionids, Anodonta woodiana and Unio douglasiae, in ambient eutrophic lake waters. Ecol Eng. 37(12):1957–1967. [Google Scholar]
  9. Li FJ, Wu NQ, Lu HY, Zhang JP, Wang WL, Ma MZ, Zhang XH, Yang XY.. 2013. Mid-Neolithic exploitation of mollusks in the Guanzhong basin of northwestern China: preliminary results. PLOS One. 8(3):e58999. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Liu Y, Xie P, Wu XP.. 2009. Grazing on toxic and non-toxic Microcystis aeruginosa PCC7820 by Unio douglasiae and Corbicula fluminea. Limnology. 10(1):1–5. [Google Scholar]
  11. Maoka T, Ochi J, Mori M, Sakagami Y.. 2012. Identification of carotenoids in the freshwater shellfish Unio douglasiae nipponensis, Anodonta lauta, Cipangopaludina chinensis laeta, and Semisulcospira libertina. J Oleo Sci. 61(2):69–74. [DOI] [PubMed] [Google Scholar]
  12. Nam KW, Lee JR, Park KI.. 2015. Utilizing the grazing effect of fresh water clams (Unio douglasiae) for the remediation of algal bloom during summer. Korean J Malacol. 31(1):61–67. [Google Scholar]
  13. Nishio M, Tanaka H, Tanaka D, Kawakami R, Edo K, Yamazaki Y.. 2016. Managing water levels in rice paddies to conserve the itasenpara host mussel Unio douglasiae nipponensis. J Shellfish Res. 35(4):857–863. [Google Scholar]
  14. Ouyang JX, Wu XP, Ouyang S, Li SB, Xu ZG.. 2013. Applicability of microsatellite markers in freshwater unionids. Biotechnology. 23(03):53–56. [Google Scholar]
  15. Takaki K. 1992. Population density and growth of Unio douglasiae and Lanceolaria grayana (bivalvia: Unionidae) in a small creek at Kyoto. Jpn J Malacol. 51:219–224. [Google Scholar]
  16. Wang HT. 2017. Analysis and comparison of the metal elements in Unio douglasiae muscle tissue. Chin J Anal Lab. 36(05):403–405. [Google Scholar]
  17. Wang H, He LP, Yang XX, Yang SB, Li C, Wang XR.. 2016a. Determination of the complete mitochondrial genome sequence of mussel Cristaria plicata (Leach). Mitochondrial DNA Part A. 27(2):1478–1479. [DOI] [PubMed] [Google Scholar]
  18. Wang Y, Liu LS, Shu JM, Zhu YZ, Li L, Zhou J.. 2013. In situ enclosure experiment on influence of different biological combination on water quality in Baiyangdian Lake. Wetland Sci. 11(03):359–365. [Google Scholar]
  19. Wang GL, Xue T, Chen ML, Guo LP, Li JL.. 2016b. Complete F-type mitochondrial genome of freshwater mussels Unio douglasiae. Mitochondrial DNA Part A. 27(6):4021–4022. [DOI] [PubMed] [Google Scholar]
  20. Watanabe MF, Park HD, Kondo F, Harada K, Hayashi H, Okino T.. 2006. Identification and estimation of microcystins in freshwater mussels. Nat Toxins. 5(1):31–35. [DOI] [PubMed] [Google Scholar]
  21. Wei QS, Fu CH, Wang YF, Fu XF.. 1994. Comparative studies on morphology of the glochidia of six mussl species (mollusca: Unionidae). Acta Hydrobiol Sin. 18(4):303–308. [Google Scholar]
  22. Wu XP, Liang YL, Wang HT.. 1999. A comparative study on glochidial morphology of unionidae (bivalvia)–I.Unio douglasiae, Cuneopsis pisciulus, Acuticosta chinensis and Acuticosta ovata. Acta Hydrobiol Sin. 23(2):3–5. [Google Scholar]
  23. Xiao JZ, Liu XM, Liu YB, Xu L, Ouyang S, Chen JK, Lei GC, Wu XP.. 2012. Distribution and abundance of freshwater mussels along the middle and lower reaches of the Ganjiang River, Jiangxi. Resour Environ Yangtze Basin. 21(11):1330–1335. [Google Scholar]
  24. Xiong LF, Ouyang S, Chen TH, Qi T, Wu XP.. 2010. The resource status and spatio-temporal variation of freshwater mussel in Qinglan Lake of Jiangxi province. J Zhejiang A&F Univers. 32(06):1257–1264. [Google Scholar]
  25. Xu BH, Xiao TY, Su JM, Jiang H, Ge XK.. 2009. Genetic diversity based on RAPD of the fifteen wild freshwater mussel species in South Dongting Lake. J Hunan Agric Univ. 35(01):88-91 + 103. [Google Scholar]
  26. Xue TT, Liu XJ, Wu RW, Ouyang S, Wu XP.. 2019. Standing stock and spatial distribution pattern of unionids in Lake Taihu, China. J Lake Sci. 31(1):202–210. [Google Scholar]
  27. Yokoyama A, Park HD.. 2003. Depuration kinetics and persistence of the cyanobacterial toxin microcystin-LR in the freshwater bivalve Unio douglasiae. Environ Toxicol. 18(1):61–67. [DOI] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Data Availability Statement

The data that support the findings of this study are freely available at NCBI GenBank database (https://www.ncbi.nlm.nih.gov) with a accession no. MT764726. And the data that support the findings of this study are also available from the corresponding author, Dr. Yang, upon reasonable request.

Articles from Mitochondrial DNA. Part B, Resources are provided here courtesy of Taylor & Francis

RESOURCES