The gill transcriptome of threatened European freshwater mussels

Abstract

Genomic tools applied to non-model organisms are critical to design successful conservation strategies of particularly threatened groups. Freshwater mussels of the Unionida order are among the most vulnerable taxa and yet almost no genetic resources are available. Here, we present the gill transcriptomes of five European freshwater mussels with high conservation concern: Margaritifera margaritifera, Unio crassus, Unio pictorum, Unio mancus and Unio delphinus. The final assemblies, with N50 values ranging from 1069-1895 bp and total BUSCO scores above 90% (Eukaryote and Metazoan databases), were structurally and functionally annotated, and made available. The transcriptomes here produced represent a valuable resource for future studies on these species' biology and ultimately guide their conservation.

Fig. 1

Maps of the five species’ potential distributions produced by overlapping points of recent presence records (obtained from Lopes-Lima et al.) with the Hydrobasin level 5 polygons. Overlapping distribution polygons between Unio mancus and Unio crassus are represented by a light purple shade, in the left panel. Overlapping distribution polygons between Unio pictorum and Margaritifera margaritifera are represented by an orange shade, in the right panel.

Fig. 2

Bioinformatics pipeline applied for the transcriptome assembly and annotation. Auxiliary representative figures were created with BioRender.com.

Fig. 3

FastQC quality report of the trimmed and decontaminated RNA-seq reads (after Centrifuge for each species. (a) Margaritifera margaritifera; (b) Unio crassus; (c) Unio pictorum; (d) Unio mancus; and (e) Unio delphinus.