Abstract
The narrow-clawed crayfish Pontastacus
leptodactylus (Eschscholtz , 1823) is an important cultured crayfish species in Iran. For further genetic improvement, however, our current knowledge of genetic resources in this species remains very limited. We conducted comparative analysis of the gills transcriptomes of P. leptodactylus from two different environments (Caspian Sea and Aras reservoir) based on Illumina RNA-seq technology. The transcriptome sequencing of cDNA libraries generated 419.2 million clean reads, the N50 and mean length of the identified 78895 unigenes were 1648 and 864 bp, respectively. A total of 3,759 differentially expressed genes (DEGs) were obtained between the two environments, of which 1,443 predicted to be up-regulated in Aras reservoir and 2,316 in Caspian Sea samples. A total of six differential genes related to the osmoregulation were selected. The qPCR analysis showed that the expression changes of these six differential genes were consistent with the results of transcriptome sequencing. Total number of filtered SNPs for Caspian Sea and Aras reservoir samples were 259 and 193, respectively. In addition, total number of identified single sequence repeats (SSRs)
were 14,235. The putative DEGs between the gills provide an important source of information for further study of the osmoregulation related genes in P. leptodactylus as well as development of molecular markers.
Keywords: Pontastacus
leptodactylus, Gene annotation, De novo assembly, Osmoregulation