Extracellular proteins of fungal pathogens are candidate effector mole-cules. We have cloned a large number (∼300) of putative secreted proteins from Magnaporthe oryzae. The proteins were fused to a His(× 6) tag to allow for affinity purification of the proteins. The genes were transformed into M. oryzae to test for expression. Approximately one-third of the genes could be expressed and secreted to sufficient levels to allow detection by western blot analysis of culture filtrates. In most cases, constitutive expression of the proteins in the transformed strains did not markedly alter their interaction with rice. However, a number of transformed lines may have reduced aggressiveness as a result of protein expression. Proteins were purified from culture filtrates of M. oryzae and symptoms were observed on rice leaves in only very few cases. The results to date are summarized and the resources developed in the project are being used for functional analysis of secreted protein. The resources generated are being distributed to facilitate functional characterization of the secretome of M. oryzae