Background: The Pacific white shrimp (Litopenaeus vannamei) is one of the most economically important shrimp species in aquaculture due to its rapid growth, favorable feed conversion ratio, and relative resistance to certain diseases. However, the emergence of Acute Hepatopancreatic Necrosis Disease (AHPND) has become a major threat to the shrimp farming industry. Antimicrobial peptides, particularly members of the penaeidin family, constitute key components of the shrimp innate immune system, and genetic variation in the genes encoding these peptides may influence susceptibility or resistance to pathogenic infections.
Aim: This study aimed to identify the single nucleotide polymorphism (SNP) at the g.664T/G locus of the PEN2-1 gene and to investigate its association with resistance to AHPND in Pacific white shrimp (Litopenaeus vannamei).
Methodology: A total of 142 shrimp samples, including 69 AHPND-resistant and 73 AHPND-susceptible individuals, were collected from infected shrimp farms in Bushehr, Iran. Genomic DNA was extracted, and the fragment containing the g.664T/G locus of the PEN2-1 gene was amplified using the tetra-primer amplification refractory mutation system polymerase chain reaction (Tetra-ARMS-PCR). Genotypes were subsequently determined, population genetic parameters were estimated, and the association between genotypes and resistance to AHPND was evaluated using statistical analyses performed in SAS software (version 9.4).
Results: The results confirmed the presence of a single nucleotide polymorphism at the g.664T/G locus. The G allele was significantly associated with resistance to AHPND, with a significantly higher frequency in resistant shrimp than in susceptible individuals (P < 0.05).
Conclusions: The findings of this study suggest that the g.664T/G locus of the PEN2-1 gene may serve as a promising molecular marker for marker-assisted selection (MAS) programs aimed at improving resistance to AHPND in Pacific white shrimp.
