Ophiocordyceps flavida sp. nov. (Ophiocordycipitaceae), a new species from Thailand associated with Pseudogibellula formicarum (Cordycipitaceae), and their bioactive secondary metabolites

During a diversity study of entomopathogenic fungi in an agricultural ecosystem, two fungi were collected, isolated, and identified based on molecular phylogenetic analyses of three nuclear loci (LSU, TEF1, and RPB1) combined with morphological data. In this study, one novel species is described, Ophiocordyceps flavida, and a new record of Pseudogibellula formicarum for Thailand. Ophiocordyceps flavida morphologically resembles the Hirsutella anamorph of Ophiocordyceps pruinosa by having a mononematous character of the conidiophores and the same insect host (Hemiptera: Cicadellidae). Pseudogibellula formicarum is found to occur simultaneously with O. flavida, producing white conidiophores on the host. Additionally, secondary metabolites of both fungi were investigated and the major compound in O. flavida was identified as 2-[2-(4-chlorophenyl)ethyl]-2-(1,1-dimethylethyl)-oxirane. Pseudogibellula formicarum from Ghana and Thailand produces 6-methoxy-1H-indole-3-carbonitrile as a main component. These compounds are known from chemical synthesis or as products of biotransformation, respectively. However, they were obtained in our study as genuine fungal metabolites for the first time and may even constitute chemotaxonomic markers for the respective species.

Automated summary

During a diversity study, two fungi, Ophiocordyceps flavida and Pseudogibellula formicarum, were identified in an agricultural ecosystem. Both fungi shared similar morphological characteristics and produced distinct secondary metabolites, with O. flavida containing 2-[2-(4-chlorophenyl)ethyl]-2-(1,1-dimethylethyl)-oxirane, and P. formicarum containing 6-methoxy-1H-indole-3-carbonitrile as the main compound. These compounds were identified as genuine fungal metabolites for the first time and could potentially serve as chemotaxonomic markers for each species.