Development of a PCR‐RFLP method for differential identification of Microcotyle sebastis and Microcotyle caudata isolated from cultured rockfish in Korea

• Published in: Journal of fish diseases Vol. 45; no. 3; pp. 411 - 419
• Main Authors: Nam, U‐Hwa, Kim, Jeong‐Ho
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.03.2022
• Subjects: Animals; Aquaculture; Aquatic reptiles; Bass; Cages; Cultured organisms; Epidemiology; Fish; Fish culture; Fish Diseases - epidemiology; Health problems; Identification; Infections; Marine fishes; Microcotyle; Microcotyle caudata; Microcotyle sebastis; Mitochondria; Nucleotide sequence; Parasites; Pattern analysis; PCR; PCR‐RFLP; Perciformes; Polymerase Chain Reaction - veterinary; Polymorphism, Restriction Fragment Length; Republic of Korea - epidemiology; Sebastes inermis; Sebastes schlegelii; Species; Urodela; Republic of Korea; Sebastes inermis; PCR-RFLP; Sebastes schlegelii; Microcotyle caudata; Microcotyle sebastis
• ISSN: 0140-7775; 1365-2761
• DOI: 10.1111/jfd.13569

Microcotylid monogeneans can cause considerable health problems in cultured fish, and several Microcotyle species are reported from scorpaenid fish, an economically important aquaculture target species in Korea. We developed a PCR‐RFLP assay targeting the mitochondrial cox1 gene, for discriminating Microcotyle sebastis and M. caudata from cultured Korean rockfish Sebastes schlegelii and dark‐banded rockfish S. inermis. AseI enzyme treatment of the PCR products showed that M. sebastis sequence was cleaved while M. caudata was not. A total of 95.2% (118/124) of monogeneans from S. schlegelii were identified as M. sebastis, and 96.2% (126/131) of monogeneans from S. inermis were identified as M. caudata by PCR‐RFLP. However, the remaining parasites from each host showed the opposite digestion pattern. Additional analyses of these specimens by targeting the ITS region by PCR‐RFLP showed the same results, suggesting that cross‐species infection by the parasites may have occurred. In Korea, S. inermis net cages are commonly located nearby S. schlegelii net cages, and this encaged proximity might have provided the opportunity for cross‐infection to occur. Further examination of wild host populations and experimental cross‐infection will be necessary to explain this phenomenon. The PCR‐RFLP method in this study will help investigate the epidemiology and infection dynamics of Microcotyle species in S. inermis.