Diversity, molecular dating and ancestral characters state reconstruction of entomopathogenic fungi in Hypocreales

Abstract

Hypocreales (Sordariomycetes, Ascomycota) is a highly diversified order, with more than 1000 entomopathogenic species being reported in Clavicipitaceae, Cordycipitaceae, Ophiocordycipitaceae and Polycephalomycetaceae.Taxa in these families form intimate associations with members of up to 13 orders of Insecta and other arthropods.Their variable morphological characteristics along with the host affiliations have played important roles in the classification of entomopathogenic species.However, it is still unclear whether these morphological characteristics are informative at the family, genus or species level in a phylogenetic context.This study focuses on entomopathogenic taxa collected from Thailand and Southwest China.Thirty-six species belonging to the above four families were identified using morphology and phylogeny inferred from combined data of LSU-SSU-5.8S-tef1-rpb1-rpb2sequences.Among them, Pleurocordyceps ophiocordycipiticola is a new species.Divergence time estimates indicated the crown age of Hypocreales at 200 Mya, while that of Clavicipitaceae was at 107 Mya, Cordycipitaceae at 129 Mya, Ophiocordycipitacae at 121 Mya and Polycephalomycetaceae at 74 Mya.Based on ancestral character state reconstruction, the ancestral ecologies of Clavicipitaceae, Ophiocordycipitaceae and Polycephalomycetaceae were animal-based, while that of Cordycipitacae was fungi-based.Multiple interkingdom jumps occurred in all entomopathogenic families.Mapping of morphological characters on the phylogeny identified cases of association of perithecial arrangement and stromal texture.Ascospore and secondary ascospores morphologies were not informative at genus and family level classifications.Expanding collections to additional hosts and environments will assist towards further understanding the diversity and ecology of hypocrealean entomopathogens.

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