Cloning and regulatory analysis of starvation-stress gene, ssgA, encoding a hydrophobin-like protein from the entomopathogenic fungus, Metarhizium anisopliae

Abstract

The nucleotide (nt) sequence of a starvation-stress gene (ssgA) of the entomopathogenic fungus, Metarhizium anisopliae, and its deduced amino acid (aa) sequence were determined. The primary structure of the SSGA (96 aa; deduced M(r) = 9925; pI = 4.1) protein shares extensive similarities with fungal wall proteins of the 'hydrophobin' class, and the eight Cys residues and putative signal sequences are conserved. Secondary structure predictions suggest an additional resemblance to low-M(r) toxins and agglutinins. Northern (RNA) blot analysis and nuclear run-on assays demonstrated transcriptional control of expression of ssgA during nutrient deprivation and during formation of infection structures. Hybridizations of M. anisopliae genomic DNA indicate that there is only one form of ssgA in the genome.