A CSDE1/Unr gene from Penaeus monodon: Molecular characterization, expression and association with tolerance to low salt stress

Abstract

The RNA-containing cold shock domain binding protein E1 (CSDE1) has been found to have a key function in immunological stress regulation. In this work, a novel CSDE1 homologue, PmCSDE1, was identified in Penaeus monodon. The full length is 4251 bp, containing a 5’-UTR of 925 bp, a 3’-UTR of 323 bp, and a 31-base poly A tail. The ORF (Open reading frame) is 3003 bp and encodes 1000 amino acids. Its relative molecular mass is 110.91 kD, and its pI is 6.77. The PmCSDE1 polypeptide sequence has five CSP structural domains and one SUZ-C motif, which may have synergistic or retrograde functions in mRNA transcriptional regulation. The results of homology analysis and phylogenetic tree analysis showed that PmCSDE1 was most closely related to P. vannamei and clustered into one group (similarity up to 95.8%), and CSDE1 was highly conserved evolutionarily among different species. Quantitative analysis showed PmCSDE1 was widely expressed in all tissues examined. After low salt stress, PmCSDE1 was significantly downregulated in hepatopancreas and gill tissues. The knockdown of PmCSDE1 resulted in a significant increase in shrimp mortality. In addition, we screened two SNPs in the genome of PmCSDE1, PmCSDE1-In3-476 and PmCSDE1-E7-166, that may be significantly associated with low-salt tolerance by chi-square tests (χ2 (P) < 0.05). The findings are expected to provide a foundation for P. monodon resistance breeding research as well as preliminary data for the investigation of low-salt tolerant strains.