Host specificity of Eupenicillium ochrosalmoneum, E. cinnamopurpureum and two Penicillium species associated with the conidial heads of Aspergillus.

The genus Penicillium comprises species that mostly colonize plant matter. However early reports suggest that several species are capable of parasitizing Aspergillus and sporulating on the conidial heads of the host. More recently Eupenicillium ochrosalmoneum and E. cinnamopurpureum, both with Penicillium anamorphs, have been observed sporulating on the heads of Aspergillus species belonging to section Flavi during the colonization of peanut seeds. Little is known about the host specificity underlying these Aspergillus-Penicillium associations. In this study Aspergillus species representing nine taxonomic sections were paired in culture with E. ochrosalmoneum, E. cinnamopurpureum and two unnamed Penicillium species. Eupenicillium ochrosalmoneum, E. cinnamopurpureum and Penicillium sp. 1 sporulated predominantly on the heads of section Flavi species. In contrast Penicillium sp. 2 was restricted to the heads of section Nigri species. All species spread across Aspergillus colonies by means of aerial hyphae that grew from head to head. Additional studies are required to clarify whether Eupenicillium and Penicillium species are parasitic or simply epibiotic on their hosts.