MOLECULAR DIAGNOSIS OF MARTEILIA-SYDNEYI (PARAMYXEA) IN SYDNEY ROCK OYSTERS, SACCOSTREA-COMMERCIALIS (ANGAS)

To prepare a diagnostic test, the polymerase chain reaction (PCR) with universal primers was used to amplify the internal transcribed spacer 1 (ITS1) of Marteilia sydneyi rDNA: A radiolabelled probe for M. sydn eyi comprising putative ITS1 rDNA gave a strong signal for genomic DNA from M. sydneyi and no signal for host genomic DNA in Southern blots. A PCR to detect M. sydneyi used a forward primer designed from an int ernal site within the sequenced region and a reverse universal primer. It amplified a 650-bp fragment of M. sydneyi DNA when a combination o f host and parasite DNA, extracted from an infected oyster, was used a s the template.