Revision of taxonomic status of several Isaria-like strains

Abstract:

[Background] Isaria farinosa with global distribution and wide host range is one of common entomopathogenic fungi in natural environment. However, the morphological characteristics of many species of Isaria are similar, which are easy to be confused only according to the classical morphological identifications. For a long time, more and more controversies and confusions have emerged on the accurate classification status of the strains identified as I. farinosa according to their morphological characteristics. Recently, its phylogeny has proved multigenus. [Objective] To clarify the taxonomic position of I. farinosa and explore the natural taxonomic status of the strains which were previously identified as I. farinosa. [Methods] Six strains previously identified as I. farinosa were selected for phylogenetic analysis of five gene loci (nrSSU, nrLSU, TEF, RPB1 and RPB2) and morphological methods to reconfirmed their taxonomic status. [Results] Through checking on the literature and experimental research, the phylogeny of I. farinosa was clarified. The results showed that all the tested strains from different sources were far related to the model strain of I. farinosa, but they are identical to a new combination species Samsoniella hepiali. [Conclusion] In this study, the correct taxonomic status of 6 Isaria-like strains was revised as S. hepiali by using the classical morphological characteristics and constructing the five genes phylogenetic tree. To provides a reasonable method for the correct identification of Isaria-like fungi and scientific guidance for further utilization of these strains.