Entomopathogenic fungus Beauveria: Host specificity, ecology and significance of morpho-molecular characterization in accurate taxonomic classification

Abstract

Beauveria species are the most common cosmopolitan insect-pathogenic fungi which parasitize over 700 insect species. Since the establishment of the Beauveria genus in 1912 by Vuillemin, its taxonomy status was relied particularly on classical morphological characters. Although easily distinguishable as a genus, species identification remains definitely complicated because of the lack of distinctive morphological features. Furthermore, the extensive overlap in conidia shape and dimensions among Beauveria species has limited their utility as key taxonomic structures. Species identification using only ITS region of rDNA as a DNA barcode reached its resolution limit within Beauveria. Recently, there is a tendency to move towards an integrative multi-locus delimitation system for closely related species. Up until now, a total of 17 Beauveria species have been established essentially reliant on the multi-genes barcode approach of four nuclear genes, i.e., RPB1, RPB2, TEF-1α and intergenic Bloc, adapting genealogical concordance phylogenetic species recognition criterion. This report reviews the taxonomic history of Beauveria species using both morphological and molecular data over the past century.