Alternatively spliced SMN orthologue in Magnaporthe oryzae is required for stress resistance and disease development

Abstract

Survival motor neuron protein (SMN) plays essential roles in cell viability and stress responses in higher eukaryotes. However, little is known about the orthologs in fungi except for the only studied yeast SMN. Here, we identified an S MN-like gene in M agnaporthe o ryzae (MOS). Bioinformatics and Southern blot confirmed that MOS is a single copy located on M. oryzae chromosome. But it was detected to contain three transcript isoforms according to RT-PCR identification. Expression patterns of these transcripts revealed that MOS is associated with stress response and conidiogenesis process in M. oryzae. Disruption mutant and its complemented strain (ΔMOS, ΔMOS/MOS) were genetically created in this study. Through biological comparison, we found that ΔMOS, with no more phenotypic defects except for reduced pigmentation and conidiation, was sensitive to oxidative, osmotic, and nitrogen or carbon-starved stresses, suggesting MOS is required for environmental adaption and basic metabolism. Infection assay further indicated MOS contributed to the development of rice blast. Therefore, we suggest that MOS as a pathogenic gene may be a potential target for reducing disease and implications in crop protection.