The interaction between Magnaporthe oryzae S3 and rice was elucidated at the cellular and molecular level. The interactions at the cellular level was observed under SEM where the level of inter and intracellular proliferation of the microbe in three rice varieties was tested yielding Pongsu Seribu as the most resistant. Through DAB assays we detected reactive oxygen species (ROIs) being expressed at the location of pathogen proliferation. In Pongsu Seribu the location of proliferation and the neighboring cells showed elicitation of ROIs. As ROIs are known to trigger defense response, the expression of a defense gene, Pathogenesis related gene(PR-1b), was quantified in rice varieties in response to infection. Pongsu Seribu showed the highest level of PR-1b gene expression that is in line with the variety being the most resistant.