Characterization of transforming growth factor beta regulator 1-like and association between its expression levels and growth of the giant tiger shrimp Penaeus monodon

Molecular markers that allow selection of juveniles and broodstock with improved growth performances are useful for the shrimp industry. Here, the full-length cDNA of transforming growth factor beta regulator 1-like (PmTbrg1-l) in the giant tiger shrimp Penaeus monodon was determined. It was 1184 bp in length and contained an open reading frame (ORF) of 975 bp corresponding to a deduced polypeptide of 324 amino acids. Successful RNA interference (RNAi) carried out using juveniles injected with PmTbrg1-l dsRNA revealed reduced levels of PmTbrg1-l and myostatin (PmMstm) in hemocytes when compared to shrimp injected with saline solution and GFP dsRNA (P<.05). Associations between single-strand conformational polymorphism (SSCP) patterns or single nucleotide polymorphism (SNP) patterns and growth-related parameters (average body weight and total length) were examined. Juveniles with pattern III (corresponding to A/A(918); N = 37) showed a trend for greater average body weight and total length than those with patterns II (G/G(918); N = 42) and IV (A/G(918); N = 75). The expression level of PmTbrg1-l in the hepatopancreas of females was significantly higher than that in males (P<.05) in two sample sets of three-month-old domesticated juveniles (N = 59 and 50; P<.05). Moreover, its expression level in large-size juveniles was significantly higher than that in medium-size and small-size juveniles in both groups of samples (P<.05). Results indicated that PrnTbrg1-l is functionally related with growth of P. monodon.