Phylogeny and species delimitations in the entomopathogenic genus Beauveria (Hypocreales, Ascomycota), including the description of B. peruviensis sp. nov

Abstract

The genus Beauveria is considered a cosmopolitan anamorphic and teleomorphic genus of soilborne necrotrophic arthropod-pathogenic fungi that includes ecologically and economically important species. Species identification in Beauveria is difficult because of its structural simplicity and the lack of distinctive phenotypic variation. Therefore, the use of multi-locus sequence data is essential to establish robust species boundaries in addition to DNA-based species delimitation methods using genetic distance, coalescent, and genealogical concordance approaches (polyphasic approaches). In this regard, our study used multilocus phylogeny and five DNA-based methods to delimit species in Beauveria using three molecular makers. These polyphasic analyses allowed for the delimitation of 20-28 species in Beauveria, confirming cryptic diversity in five species (i.e. B. amorpha, B. bassiana, B. diapheromeriphila, and B. pseudobassiana) and supporting the description of B. peruviensis as a new taxon from northeastern Peru. The other five species were not evaluated as they did not have enough data (i.e. B. araneola, B. gryllotalpidicola, B. loeiensis, B. medogensis, and B. rudraprayagi). Our results demonstrate that the congruence among different methods in a polyphasic approach (e.g. genetic distance and coalescence methods) is more likely to show reliably supported species boundaries. Among the methods applied in this study, genetic distance, coalescent approaches, and multilocus phylogeny are crucial when establishing species boundaries in Beauveria.

Keywords: Beauveria; Peru; fungal diversity; multi-locus phylogeny; polyphasic approaches; species delimitation.

Figure 1.

Collections of the 55 strains of B. amazonensis sp. nov. from the Rodriguez de Mendoza Province.

Figure 2.

Phylogenetic tree based on maximum likelihood inference of combined Bloc, RPB1, Tef1 data. Value above branches = Maximum likelihood bootstrap values (BS) / Bayesian posterior probabilities. Grey bars represent species delimitation results from ABGD-, SPN-, GMYC- and BPP based algorithmic methods based on Bloc, RPB1, and Tef1 sequences. Scale bar indicates the number of nucleotide substitution per site. a: delimited as the same species. B. araneola, B. gryllotalpidicola, B. loeiensis, B. medogensis, and B. rudraprayagi were not delimited by any DNA-based algorithm due to abundant missing data in their sequences.

Figure 3.

Morphology of Beauveria amazonensis. A, B Colony growth on PDA showing the habit C–F conidiogenous cells and conidia.