1.2.29
DIFFERENTIATION OF PEA POWDERY MILDEW HAUSTORIA

D BAINES-PINCHEN, JA CALLOW and JR GREEN

School of Biological Sciences, University of Birmingham, Birmingham B15 2TF, UK

Background and objectives
Interaction of powdery mildew fungi with a susceptible host leads to the formation of a special infection structure known as the haustorial complex (HC). This has several important roles in the disease process. Elucidating the structure, composition and functions of the interfacial region between the host and parasite is fundamental to understanding the role of the HC in biotrophic parasitism. We are studying the molecular nature of the interface formed in the interaction between Erysiphe pisi and Pisum sativum [1]. In previous work we have identified glycoproteins that are specific to the HC and several that are common to the HC and either the host or the fungus [1].

Results and conclusions
Two new monoclonal antibodies (MAbs) have been raised to isolated HCs. MAb UB44 (IgG1) recognises a protein (63 kDa) that is localized to the HC interior and is also present in the host and fungal mycelium. The antigen appears to be highly conserved in other plant species. MAb UB46 (IgM) recognises a protein (70 and 65 kDa) that is localized to the HC periphery (extrahaustorial membrane) and is also present in the host. The antigen is also present in many other plant species. These antibodies are currently being used to immunoscreen cDNA expression libraries.

References
1. Green JR et al., 1995. Canadian Journal of Botany 73 (Suppl. 1), 408-417.