Differential expression of X-box binding protein 1 during ovarian development and association between its SNP and growth-related parameters of the giant tiger shrimp Penaeus monodon

The full-length cDNA of X-box binding protein 1 (PmXbp1) in the giant tiger shrimp, Penaeus monodon was identified. It was 1762 bp in length containing an ORF of 855 bp corresponding to 284 amino acids. The expression level of PmXbp1 in different ovarian stages of wild intact broodstock was comparable but greater than that of cultured juveniles (P < 0.05). Eyestalk ablation resulted in up-regulation of PmXbp1 in stages III (late vitellogenic) and IV (mature) ovaries of wild P. monodon broodstock (P < 0.05). Exogenous serotonin injection (5-HT, 50 mu g/g body weight) potentially promoted the expression of PmXbp1 in ovaries of domesticated 18-month-old broodstock at 24 hpi (P < 0.05). In addition, single nucleotide polymorphisms (SNPs) in PmXbp1 (185 bp) were examined in domesticated 3-month-old juveniles (average body weight and total length = 12.32 +/- 5.13 g and 11.30 +/- 1.58 cm, N = 162) by single-strand conformational polymorphism (SSCP) analysis. Association between SSCP patterns of PmXbp1 and growth-related parameters was found where the average body weight (15.07 +/- 5.04, N = 44) of juveniles carrying pattern A (corresponding to a T/T349 SNP) was significantly greater than that (11.37 +/- 4.80, N = 116) of juveniles carrying pattern B (corresponding to a T/C349 SNP). The relative expression levels of PmXbp1 in the hepatopancreas of juveniles carrying different SSCP/SNP genotypes were significantly different (A < B; P < 0.05). In addition, the level of PmXbp1 in shrimp exhibiting a greater growth performance (22.08 +/- 2.97 g and 13.60 +/- 0.56 cm; N = 11) was significantly lower than that with a lesser growth performance (5.00 +/- 0.89 g and 8.60 +/- 0.98 cm; N = 8) (P < 0.05). Taking the information together, PmXbp1 seems to play an important role in reproduction and growth of P. monodon. Statement of relevance: In aquaculture, the primary goal of genetic selection is the growth improvement of economically important species. Molecular markers that allow for selection of juveniles and broodstock with a high breeding value for reproductive maturation and/or growth rates are useful for the shrimp industry. Information on correlation between genotypic and phenotypic variations in penaeid shrimp is rather limited. Identification of molecular markers linked with growth/reproduction or those regulating the growth/reproduction mechanisms can be applied to improve artificial selection processes of P. monodon. To assess the possible biological roles of X-box binding protein 1 in reproduction and growth of P. monodon, the PmXbp1 cDNA sequence was characterized. Expression patterns of PmXbp1 during ovarian development in wild P. monodon broodstock were examined. Effects of eyestalk ablation (wild broodstock) and serotonin induction (domesticated broodstock) on expression levels of ovarian PmXbp1 were examined. In addition, analysis of relationships between SNP detected by SSCP and DNA sequencing and expression levels of PmXbp1, and growth traits in juvenile shrimp was examined. (C) 2015 Elsevier B.V. All rights reserved.