Gibellulopsis, a suitable genus for Verticillium nigrescens, and Musicillium, a new genus for V. theobromae
Zare, R. Gams
Verticillium nigrescens is not congeneric with Verticillium s. str., as shown in cladograms based on LSU and ITS sequences. Both genera and a few other taxa form a separate, new family, the Plectosphaerellaceae, in which Plectosphaerella cucumerina is the only known teleomorph taxon. The species is conspecific with Gibellulopsis piscis, which provides a suitable generic name. The available isolates are not completely homogeneous as shown in tef1 analysis. This frequent saprotrophic species is neotypified with an isolate from a Dutch soil. It has hyaline, rather short conidiophores arising from vegetative hyphae generally in terminal position, with one or two scant whorls of aculeate phialides. Brown, intercalary or terminal chlamydospores give the colony a more or less dark grey aspect. In the same family, the causal agent of cigar-end rot of bananas, Verticillium theobromae, is also generically distinct and described in the new genus Musicillium. The species is also neotypified with an Egyptian isolate. It has long, brown conidiophores, bearing several nodes, each with whorls of 3-6 aculeate phialides, no chlamydospores, but chains of monilioid cells that gradually darken.