Molecular identification and phylogenetic analysis of the mitogenome of Solenaia oleivora MG

Abstract Solenaia oleivora, belongs to Bivalvia, Unionidae, and Gonideinae, is a burrowing bivalve uniquely distributed in China. In this study, the complete mitochondrial genome of S. oleivora MG was sequenced and determined. The complete mitogenome of S. oleivora MG is 16,392 bp in total length, consist of 22 tRNA genes, 13 protein-coding genes (PCGs), and 2 rRNA genes. The overall base composition of the S. oleivora MG mitogenome is 36.90% A, 23.85% T, 27.09% C, and 12.16% G, respectively, exhibits a similar AT bias (60.75%) feature to other invertebrate bivalve mitogenomes. The phylogenetic analysis that S. oleivora MG clustered in genus Solenaia. This result provides useful data to the conservation and sustainable utilization of S. oleivora MG and other invertebrate mussels.

Solenaia oleivora MG; mitogenome; molecular identification; phylogenetic analysis Solenaia oleivora, belongs to Bivalvia, Unionidae, Gonideinae, is a burrowing bivalve uniquely distributed in Hunan, Hubei, Jiangxi, Zhejiang, Jiangsu, Anhui, and Henan province of China (Xu et al. 2005(Xu et al. , 2006(Xu et al. , 2013Li et al. 2012;Wang et al. 2015;Wu et al. 2018;Bolotov et al. 2019). It is an economically important freshwater mollusk with fast growth, large individuals, and high nutritional value (Xu et al. 2003(Xu et al. , 2005(Xu et al. , 2008Yang et al. 2011). However, in recent years, its wild population declines rapidly because of water pollution and increasing capture pressure (Xu et al. 2005;Huang et al. 2015;Zhang et al. 2020). Identification of the complete mitochondrial genome, and make clear its phylogenetic relationships with other closely related species is necessary for the conservation and sustainable utilization of S. oleivora and other aquatic species (Tzeng et al. 1992;Liu and Cui 2009;Min and Park 2009;Chen et al. 2013;Huang et al. 2013;He et al. 2014;Wu et al. 2019).
The complete mitochondrial genome of S. oleivora MG is 16,392bp in length, deposited in GenBank database with an accession number MT477834. It consists of 22 tRNA genes, 13 protein-coding genes (PCGs), and two rRNA genes. It is gene structure and arrangements are similar to the typical bivalve mitogenomes (Huang et al. 2013;Huang et al. 2015).
The total length of the protein-coding gene sequences is 11,118 bp. Except for the ND6 is encoded on the L-strand; all the other PCD genes (ND1-5 and ND4L, COXI-III, ATP6, ATP8, and CytB) are encoded on the H-strand. The total length of all tRNA genes is 1433 bp, varying from 61 bp (tRNA Gly ) to 71 bp (tRNA Ala ). The 12S rRNA gene (843 bp) and 16S rRNA (1287 bp) gene are located between two tRNA genes (tRNA Arg and tRNA Leu ), and are separated by tRNA Lys , tRNA Thr , and tRNA Tyr genes. The gene structure and arrangement of S. oleivora MG are very similar to other mollusks (Huang et al. 2013). The overall base composition of the S. oleivora MG mitogenome is 36.90% A, 23.85% T, 27.09% C, and 12.16% G, respectively, exhibits an obvious and similar AT bias (60.75%) feature to other invertebrate bivalve mitogenomes (Huang et al. 2013;Yang et al. 2015).
The phylogenetic tree was constructed using the neighbor-joining method. The results showed that S. oleivora MG is clustered with other Solenaia mussels including S. oleivora (Huang et al. 2015), S. carinatus (Huang et al. 2013), and S. carinatus (GenBank accession number: NC_039839) (Figure 1).
While it showed distant kinship with other shellfishes like Lamprotula caveata (GenBank accession number: NC_030336) and Alasmidonta varicosa (GenBank accession number: NC_038155). This study provides useful data to the conservation and sustainable utilization of S. oleivora MG and other invertebrate bivalves.

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 openly available at NCBI (https://www.ncbi.nlm.nih.gov), GenBank accession no. MT477834. And the data that support the findings of this study are also available from the corresponding author, Dr. Yang, upon reasonable request.