High-quality genome and transcriptome resources for the East Asian freshwater mussel Nodularia douglasiae

Nodularia douglasiae is a freshwater mussel widely distributed across East and Southeast Asia. This species belongs to the order Unionida, many of which are globally threatened. Unionid mussels play significant ecological roles in freshwater ecosystems, and their life cycle includes a parasitic larval stage that depends on freshwater fishes for development and dispersal. Despite their ecological and conservation significance, genomic resources for unionids remain underrepresented. Here, we report the first genome assembly and transcriptome data for the genus Nodularia. Using PacBio reads, polished with Illumina data, and scaffolded via error-corrected long reads, we generated a 1.98 Gb unique haplotig genome assembly with 3,060 scaffolds (N50: 1.62 Mb). A total of 36,556 protein-coding genes were predicted, with 98.2% BUSCO completeness against the metazoan database. Transcriptome analysis across four different tissue types (adductor muscle, foot, gill, and mantle) revealed 5,253 differentially expressed genes (DEGs), with 3,242 assigned Gene Ontology terms. These high-quality genomic resources provide a valuable reference for comparative genomics, evolutionary and ecological studies, and conservation of threatened freshwater mussels.