Characterization and structure of the mitochondrial small rRNA gene of the entomopathogenic fungus Beauveria bassiana.

The entire mitochondrial (mt) small ribosomal RNA (srRNA) gene from the entomopathogenic fungus Beauveria bassiana was sequenced. Alignment of the sequence to those of other filamentous fungi revealed gross length differences in their respective products. Construction of a secondary structural model showed that these differences were restricted to known variable srRNA subdomains. Several features were identified that were common only to the hyphomycetous fungi examined. Phylogenetic analysis indicated that the anamorph B. bassiana was more closely related to the pyrenomycete than to the plectomycete ascomycetous fungi. Based on our previous comparison of mt gene arrangement in filamentous fungi, this was unexpected. The possibility that the smaller mt genomes reflect the ancestral arrangement of genes is discussed.