Cloning and expression of cDNA encoding a mitogen-activated protein kinase from a phytopathogenic filamentous fungus.

We have cloned a mitogen-activated protein kinase (MAPK) designated Fusarium solani f. sp. pisi mitogen-activated protein kinase (FsMAPK) from the phytopathogenic filamentous fungus F. solani f. sp. pisi T8 strain. A single open reading frame (ORF) of 1068 bp encoding a polypeptide of 355 amino acids (aa) with a predicted molecular mass of 41,194 Da was found in the cloned 1583-bp cDNA insert. FsMAPK is highly homologous to SPK1 of fission yeast, FUS3 of budding yeast, MsERK1 of alfalfa, Sur-1 of nematode, and hERK1 of human. That this gene is expressed in F. solani f. sp. pisi was shown by the finding that immunoblot of the fungal extracts with anti-FsMAPK antibodies (Ab) raised in a rabbit against the FsMAPK, expressed in Escherichia coli (E. coli), detected the corresponding protein. DNA blot analysis indicated that Fsmapk is present as a single copy in the fungal genome.