LOCALIZATION OF CALMODULIN IN FLAGELLA OF ZOOSPORES OF PHYTOPHTHORA-CINNAMOMI

Calmodulin distribution in the tinsel and whiplash flagella of zoospores of Phytophthora cinnamomi has been studied by immunofluorescence microscopy and immunogold labelling. In whole zoospores labelled with a monoclonal antibody raised against pea calmodulin, followed by a second antibody-FITC, both flagella appear to be weakly stained except for a region at the base of the tinsel flagellum which was stained intensely. A similar staining pattern was also detected in isolated flagella labelled with anti-calmodulin. To identify the calmodulin rich region of the tinsel flagellum, we labelled sections of zoospores embedded in Lowicryl K4M with anti-calmodulin followed by a second antibody gold probe. In the tinsel flagellum, the gold labelling was restricted to a paraxonemal swelling close to the base. Very little gold labelling was detected elsewhere. The swelling extends for 1.5-2.0 μn from the base of the tinsel flagellum and is hook shaped in cross section. Immunoblot analysis confirmed that the staining was specific for calmodulin. © 1990 Springer-Verlag.