The rice blast, caused by fungus Magnaporthe oryzae, is a major constraint to the world food security. Hyphal growth is the foundation of fungal development and proliferation of fungi. To investigate genes involved in hyphal growth of this fungus, digital gene expression tag profiling was used to compare a previously generated temperature-sensitive mutant which defect at hyphae growth and reduction on pathogenicity, with its related wildtype strain. 416 genes were detected as differential expression, 178 of which were specifically expressed in Guy-11 but down-regulated expression in the mutant. Functional classification analysis revealed the phenotype mutation may be mainly caused by a defection in translational and vacuolerelated processes. The results and the protocol used will improve our knowledge on morphogenesis and promote the further study on M. oryzae pathogenesis.

Magnaporthe oryzae, a filamentous ascomycete fungus, is well known as the causal agent of rice blast. With thetechnology of suppression subtractive hybridization (SSH), it was previously found that MGG_06001 (or named MoNEM1),a gene of M. oryzae homologous to the NEM1 (nuclear envelope morphology protein 1) gene of baker’s yeast(Saccharomyces cerevisiae), is differentially expressed between the mature appressium and the conidium and mycelium.This study aimed to characterize the function of MoNEM1 gene by knocking it out using the method of target genereplacement. The ΔMonem1 mutants exhibited reduced mycelial growth and conidiation. However, disruption of MoNEM1gene does not affect the pathogenicity of M. oryzae on barley and rice.