Development of a real-time PCR method for the detection of Vibrio splendidus based on gyrB gene

Abstract:

Vibrio splendidus is a deleterious pathogenic bacterium for most marine animals, and it causes great losses in aquaculture industry. To develop a quantitative detection method of V. splendidus is important because its pathogenicity is closely related to the population density. To develop a rapid SYBR Green I real-time fluorescence quantitative PCR method, a pair of specific primers were designed according to V. splendidus gyrB gene to determine the specificity and sensitivity. The real-time PCR amplification conditions were optimized. Recombinant plasmid containing gyrB gene of V. splendidus was constructed and used to establish the standard curve. The detection limit and reproducibility were calculated. A 251 bp fragment was amplified from chromosomal DNA, but no positive reaction was detected in 9 other bacteria species using conventional PCR, which indicated that the primer pair has good intra-species specificity and inter-species commonality. The standard curve was y=-3.338x+37.67; the correlation coefficient was 0.999 and the amplification efficiency was 0.99, indicating a good linear relationship between initial templates and CT values. The melting curve had only one specific peak when annealing temperature was 62℃. The detection limit of the assay was 20 copies per reaction. The results indicated that the established SYBR Green I real-time fluorescence quantitative PCR method for V. splendidus had high specificity, sensitivity and repeatability, which may help V. splendidus diagnosis and epidemiology.