Serological detection of red rot disease initiation stages of microbial pathogen, Pythium porphyrae (Oomycota) on Porphyra yezoensis

Pythium porphyrae (Oomycota), a pathogen causing red rot disease in Porphyra spp., can at present only be detected when colonization of the host thallus has already occurred and so it is often too late to take appropriate disease control measures. The paper presents an account of an effective methdology for early detection of the disease. Since Py. porphyrae zoospores are the primary means of pathogen dispersal, polyclonal antibodies (Pabs) were raised against the surface components of zoospores and encysted zoospores. Using these Pabs the disease initiation stages of the Pythium porphyrae were detected on the surface of Porphyra thalli by immunofluorescence assay. The specificity of these antibodies and the efficacy of immunofluorescence assay in the detection of red rot disease are discussed.