The rice-blast fungus Magnaporthe oryzae is disseminated using a three-celled spore or conidium. Upon landing on the surface of a rice leaf, the conidium germinates and forms a specialised structure for entry into the host plant - the appressorium. In this study we have followed gene expression thoughout germination of the conidium and formation of the appressorium to identify genes that may be important for appressorium function. We have also compared gene expression in the wild-type germinating conidium at four hours to a mutant strain deleted for the MAP kinase pmk1. The pmk1 mutant is unable to form appressoria. Samples were taken from five time-points in wild-type germinating conidia and one time-point in the pmk1 mutant. Two replicates were taken at each time-point.