Structure of gene coding for the fruit body-specific hydrophobin Fbh1 of the edible basidiomycete Pleurotus ostreatus.

Two fruit body-specific hydrophobins (Fbh1 and POH1) have been identified in two different strains of the edible basidiomycete Pleurotus ostreatus. Comparison of their nucleotide and amino acid sequences yielded similarity values (59% and 66%, respectively) smaller than those found for alleles of the same hydrophobin gene but higher than those found for different hydrophobin genes in P. ostreatus var. florida (Peñas et al 2002). In this paper, we have addressed the question of Fbh1 and POH1 allelism by studying the structure of the gene fbh1 and by a classical genetic analysis to compare it with that of POH1. The structure of both genes is similar, as revealed by the similarity of their promoters and leader peptide sequences and by the conserved position of their introns. Furthermore, the allelism analysis revealed that both genes segregated as alleles when present in the same hybrid. These results suggest an allelic condition for POH1 and fbh1 and stress the importance of the similarity of fbh1/POH1 promoter and leader sequences. Furthermore, we have identified various microsatellite-like regions in this gene that can be used for strain and species typing in the future.