Immunomagnetic purification of Colletotrichum lindemuthianum appressoria

We developed a method to purify appressoria of the bean anthracnose fungus Colletotrichum lindemuthianum for biochemical analysis of the cell surface and to compare appressoria with other fungal structures. We used immunomagn etic separation after incubation of infected bean leaf homogenates with a m onoclonal antibody that binds strongly to the appressoria. Preparations wit h a purity of >90% could be obtained. Examination of the purified appressor ia by transmission electron microscopy showed that most had lost their cyto plasm. However, the plasma membrane was retained, suggesting that there is some form of attachment of this membrane to the cell wall, The purified app ressoria can be used for studies of their cell surface, and we have shown t hat there are clear differences in the glycoprotein constituents of cell wa lls of appressoria compared with mycelium.