The placement of South African strains of Beauveria in a phylogeny inferred from rDNA ITS1-5.8S-ITS2 sequences

Abstract

This study aimed to confi rm the identity of three strains of the entomopathogenic fungus Beauveria bassiana from South African soils and to investigate their phylogenetic relationship with non-indigenous strains from other geographic regions. Sequences of the rDNA ITS1-5.8S-ITS2 region of 23 strains were compared with the Genbank reference sequences of 20 other cosmopolitan strains. Fitch parsimony and neighbor-joining analyses of the ITS1-5.8S-ITS2 regions resolved the strains into two distinct clades and matched them to four species groups/lineages: Beauveria bassiana, B. cf. bassiana (pseudobassiana), B. brongniartii and B. caledonica. Two of the South African strains initially identifi ed as B. bassiana grouped with B. caledonica, whereas the third strain was confi rmed as B. bassiana. Because of the paucity of Genbank references for B. caledonica, we have designated the two South African B. caledonica strains as B. sp. aff. caledonica. Other reassignments included two strains from Norway, originally classifi ed as B. bassiana, being grouped with B. brongniartii, and three of the B. brongniartii reference taxa from Brazil which were clearly placed in the B. bassiana clade. The study provides a fi rst report of the presence of the B. caledonica lineage in Africa and confi rms current Beauveria phylogenies inferred from molecular data.