Nuclear import of proteins relies on nuclear import receptors called 
importins/karyopherins (Kaps), whose functions were reported in yeasts, fungi, 
plants, and animal cells, including cell cycle control, morphogenesis, stress 
sensing/response, and also fungal pathogenecity. However, limited is known about 
the physiological function and regulatory mechanism of protein import in the 
rice-blast fungus Magnaporthe oryzae. Here, we identified an ortholog of 
β-importin in M. oryzae encoded by an ortholog of KAP119 gene. Functional 
characterisation of this gene via reverse genetics revealed that it is required 
for vegetative growth, conidiation, melanin pigmentation, and pathogenicity of 
M. oryzae. The mokap119Δ mutant was also defective in formation of 
appressorium-like structure from hyphal tips. By affinity assay and liquid 
chromatography-tandem mass spectrometry, we identified potential 
MoKap119-interacting proteins and further verified that MoKap119 interacts with 
the cyclin-dependent kinase subunit MoCks1 and mediates its nuclear import. 
Transcriptional profiling indicated that MoKap119 may regulate transcription of 
infection-related genes via MoCks1 regulation of MoSom1. Overall, our findings 
provide a novel insight into the regulatory mechanism of M. oryzae pathogenesis 
likely by MoKap119-mediated nuclear import of the cyclin-dependent kinase 
subunit MoCks1.