Analysis of a genomic clone of hydrophobin (ssgA) from the entomopathogenic fungus Metarhizium anisopliae

A 909 bp region containing a genomic clone encoding for hydrophobin (ssgA) from the entomopathogenic fungus Metarhizium anisopliae has been sequenced and the regulatory motifs analysed against those recognized in other fungi. The genomic clone was also compared with the open reading frame of the hyd rophobin ssgA (starvation stress gene) cDNA sequence. The genomic clone con tained a 291 bp coding sequence with one intron of 64 nucleotides. From thi s sequence primers were established that could be used to amplify the hydro phobin. Restriction fragment polymorphism analysis of hydrophobin amplified by the polymerase chain reaction from 80 isolates of M. anisopliae showed no variability. Analysis of the potential regulatory elements 313 bp upstre am from the transcriptional start site revealed typical TATAA and CCAAT box es. CT or GC motifs were not found. Upstream regulatory elements were also found with sequence homologies to the AREA, CREA, CRE (cAMP response elemen t) and BRLA regions of Aspergillus nidulans as well as the CYS3 and AmyB re gions of Aspergillus oryzae. The promoter regions of other fungal hydrophob ins were also assessed for the presence of regulatory elements. Upstream re gulatory elements are also present for the gene encoding a cuticle-degradin g protease (Prl) from M. anisopliae. We suggest that nutrient levels and cA MP mediation of thigmotropic signals in the entomopathogenic fungus, M. ani sopliae, co-ordinate the regulation of the gene products required for morph ological development and secretion of 'penetration' enzymes.