Cloning and characterization of a Hog1 MAPK homologous gene BbHog1 from Beauveria bassiana
球孢白僵菌Hog1 MAPK同源基因BbHog1的克隆及特征分析

Degenerate PCR primers were designed according to the conserved amino acid sequence of several filamentous fungus MAPKs which were homologous to yeast Hog1 MAPK, and partial DNA fragment encoding a MAPK was amplified from entomopathogenic fungus Beauveria bassiana using PCR. Thereafter, a whole DNA sequence encoding the MAPK, designated as BbHog1, was obtained from B. bassiana by extending upstream and downstream sequence of the amplified fragment using YADE method. Sequence analysis suggested that BbHog1 encoded a protein of 358 amino acids with Mr of 40.99KDa and PI of5.49.The BbHog1 contained the conserved TGY activation loop found in the stress-activated protein kinase subgroup of MAPKs and its amino acid sequence showed 94%,89%,83% and 80% identity to os-2(AF297032) from Neurospora crassa,OSM1 (XM_747571)from Aspergillus fumigatus,HOG1 (AF243531) from Cryptococcus neoformans var.neoformans and Hog1 (Z73285) from Saccharomyces cerevisiae,respectively.Phylogenetic clustering suggested that BbHog1 is homologous to yeast Hog1 MAPK.Southern analysis indicated that BbHog1 was present as a single copy in B.bassiana.Northern blot analysis showed that BbHog1 gene expression was obviously increased when the fungus was cultured under the condition of hyperosmotic stress,sub-high temperature and nutrition starvation,which suggested that BbHog1 gene was involved in the stress adaptation reguloation of Beauveria bassiana.