Genetic structure and diversity of Nodularia douglasiae (Bivalvia: Unionida) from the middle and lower Yangtze River drainage

Abstract

The Yangtze River drainage in China is among the most species rich rivers for freshwater mussels (order Unionida) on Earth with at least 68 species known. The freshwater mussels of the Yangtze River face a variety of threats with indications that species are declining in abundance and area of occupancy. This study represents the first analyses of the genetic structure and diversity for the common and widespread freshwater mussel Nodularia douglasiae based on microsatellite DNA genotypes and mitochondrial DNA sequences. Phylogenetic analysis a fragment of the COI mitochondrial gene indicated that N. douglasiae collected from across the middle and lower Yangtze River drainage are monophyletic with N. douglasiae from Japan, Russia, and South Korea. The results of the analysis of both the mtDNA and microsatellite datasets indicated that the seven collection locations of N. douglasiae in the middle and lower Yangtze River drainage showed high genetic diversity, significant genetic differentiation and genetic structure, and stable population dynamics over time. Moreover, we found that the connections among tributaries rivers and lakes in the Yangtze River drainage were important in maintaining gene flow among locations that N. douglasiae inhabits. An understanding of the genetic structure and diversity of a widespread species like N. douglasiae could be used as a surrogate to better understand the populations of other freshwater mussel species that are more rare in the Yangtze River drainage. At the same time, these results could provide a basis for the protection of genetic diversity and management of unionid mussels diversity and other aquatic organisms in the system.

Integrative taxonomy, biogeography and conservation of freshwater mussels (Unionidae) in Russia

“…Amur and Razdolnaya basins, coastal rivers of the Japan Sea drainage west of Nakhodka (Partizanskaya and Artemovka rivers) 54 55,58 , northwestern Sakhalin 71 ; Lake Buir (Amur Basin) in Mongolia and northeastern China 118 , eastern China (Yangtze Basin), Korea, Japan, and northern Vietnam 39,53,87 www.nature.com/scientificreports www.nature.com/scientificreports/ Distribution. Cristaria plicata was recorded throughout the Amur Basin, and in the Tym' River, central Sakhalin 51 (Figs.…”

“…Several species with broad ranges such as Anodonta anatina, A. cygnea, Beringiana beringiana, Cristaria plicata, Middendorffinaia mongolica, Nodularia douglasiae, Pseudanodonta complanata, Sinanodonta schrenkii, Unio pictorum, U. tumidus, and U. crassus, appear to be appropriate models for phylogeographic studies with a supplement of molecular data from adjacent countries such as Kazakhstan, China, Mongolia, Korea, Japan, and others. A few available works on this issue have revealed putative colonization and refugial patterns for several European and Chinese species [87][88][89][90][91] that are of great importance to reconstruct the evolutionary history of freshwater fauna in the Palearctic Region. Widespread species can also be used as models for broad-scale studies of intraspecific shell variability 92,93 .…”

Declining freshwater mussel diversity in the middle and lower reaches of the Xin River Basin: Threat and conservation

“…The Yangtze River Basin is a biodiversity hotspot for freshwater mussels, with more than 80% of them in this area are considered threatened or vulnerable (Liu et al, 2017;Shu, Wang, Pan, Liu, & Wang, 2009;Zieritz et al, 2018). Poyang Lake is the largest river-connected lake in the Yangtze River Basin with approximately 75% of the endemic freshwater mussel species in China (Li et al, 2019;Sun et al, 2018;Xiong, Ouyang, & Wu, 2013).…”

“…Knowledge on biodiversity plays an important role in the conservation and management of freshwater mussels (Liu et al, 2017;Zieritz et al, 2018Zieritz et al, , 2016. For example, beta diversity is a key concept for understanding the functioning of ecosystems, the conservation of biodiversity, and the management of ecosystems (Bergamin et al, 2017;Wiersma & Urban, 2005;Xu et al, 2019).…”

The complete mitochondrial genome of a freshwater mussel Nodularia douglasiae (Bivalvia: Unionidae)

“…Although Nodularia douglasiae (synonym Unio douglasiae; Unionidae, Unionida, Bivalvia) is one of the most common and widespread freshwater mussels in the whole river systems from Republic of Korea, and also widely and abundantly distributed in China, eastern Russia, and Japan (Liu et al 2017), it has been considered as 'Least Concern' in the last IUCN Red List assessment (Allen and Bogan 2014). Recently, Wang et al (2015) has first reported the complete mitochondrial genome of N. douglasiae from China, and Liu et al (2017) has examined phylogenetic relationships and population structure of N. douglasiae from eastern Asia with partial COI genes.…”