Exploitation of Zoospore Taxis in the Development of a Novel Dipstick Immunoassay for the Specific Detection of<i>Phytophthora cinnamomi</i>

Abstract

Species-specific monoclonal antibodies (MAbs) were used to develop a dipstick immunoassay for the detection of Phytophthora cinnamomi. The assay is based on the phenomena of chemotaxis and electrotaxis to attract zoospores in suspension to a membrane where they encyst and are detected by immunoassay. A chemotaxis assay was used to identify compounds that could be incorporated into the dipstick. The most attractive compounds included several amino acids, alcohols, phenolics, and isovaleraldehyde. Some compounds, such as pectin, aspartic acid, and the phytohormone abscisic acid, caused encystment in addition to attraction. Zoospores also exhibited strong electrotaxis to a positively charged nylon membrane [...]