Hidden diversity behind the Lecanicillium-like white colony-forming mycoparasites on Hemileia vastatrix (coffee leaf rust)

During surveys for fungal natural enemies of Hemileia vastatrix – the causal agent of coffee leaf rust (CLR) – in its African centre of origin (Cameroon, Ethiopia), as well as in its exotic South American range (Brazil, Paraguay), an eclectic and species-rich mycobiota was encountered. Here, we provide a comprehensive report on an assemblage of “white colony-forming fungi” (WCF), often treated in the earlier literature under the inadequate “label” Verticillium lecanii (= Lecanicillium lecanii ). A total of 265 isolates of WCF were provisionally placed in this arbitrary group. We clarified the identity of our assemblage of Lecanicillium-like fungi using a combination of morphological characteristics and sequence data for the large subunit nuclear ribosomal DNA (LSU), translation elongation factor 1-α ( TEF ) and the largest subunits of RNA polymerase II ( RPB1 and RPB2 ) regions. Fifteen WCF species belonging to eight genera across three hypocrealean families ( Bionectriaceae , Clavicipitaceae and Cordycipitaceae ) were found parasitizing pustules of CLR. Significantly, Lecanicillium lecanii was not found to be present amongst these taxa. Six species belonged to the known genera – Corniculantispora , Gamszarella , Lecanicillium, Ovicillium, Pleurodesmospora and Simplicillium . Two new genera are described, Bettiolomyces and Hemileiophthora , as well as seven new species, Bettiolomyces urediniophagus , Gamszarella uredinophila , Hemileiophthora denticulata, H. nodosa, Lecanicillium hemileiae , Pleurodesmospora hemileiae and Simplicillium hemileiae. The following known WCF species are recorded here for the first time on pustules of H . vastatrix : Corniculantispora dimorpha , Gamszarella buffelskloofina , Lecanicillium uredinophilum , Ovicillium attenuatum , Pleurodesmospora coccorum and Simplicillium subtropicum. Additionally, the new combination Bettiolomyces epiphytus is introduced for < em >Verticillium epiphytum</ em >.