Cryptic diversity of the genus Beauveria with a new species from Thailand

Thailand has rich natural resources and diverse ecosystems. From our surveys of entomopathogenic fungi in Thailand over the last decade, 66 Beauveria strains in BIOTEC Culture Collection (BCC) were studied to account for the diversity of this genus in Thailand. Examination of morphological characteristics from various media and phylogenetic analyses based on partial sequence of ITS, TEF, RBP1, RPB2, and the nuclear intergenic region Bloc, were realized. Among the strains from Thailand, we described here a new species, namely B. mimosiformis sp. nov., isolated from Coleoptera larva in the North of Thailand. This new species has a unique characteristic of phialides and conidia forming an ensemble similar to plant leaves of the genus Mimosa; it has pale yellow to light yellow stromata, cylindrical with rounded apices or oblong conidia, cylindrical part-ascospores. We also found a teleomorph linked to B. asiatica and documented new hosts (Lepidoptera larva and adult beetle) of B. gryllotalpidicola, as well as reported B. malawiensis for the first time in Thailand. Beside those species, B. bassiana and B. loeiensis were also identified, adding up to six species from Thailand. Through molecular phylogenetic analyses, we revealed (1) diverging lineages within B. asiatica and B. bassiana which, despite lack of support to be erected as any higher taxonomical unit, demonstrated complex intra-specific molecular diversity undergoing differentiation and (2) ambiguous relations between certain known species, particularly for B. majiangensis that we synonymized as B. asiatica.