Terverticillate penicillia isolated from underground seed caches and cheek pouches of banner-tailed kangaroo rats (Dipodomys spectabilis)

Abstract

Terverticillate penicillia were important colonists of the underground seed caches and the external cheek pouches of the banner-tailed kangaroo rat (Dipodomys spectabilis) from the North American desert. Two taxa representing the dominant Penicillium populations are described as new varieties of well-known ubiquitous species. Penicillium chrysogenum var. dipodomyis var.nov. produces the antibiotic penicillin but does not produce mycotoxins (PR-toxin and roquefortine C) known from P. chrysogenum. The new variety is further distinguished by having rough-walled stipes. Penicillium aurantiogriseum var. neoechinulatum var.nov. isolates produce penicillic acid, viridicatin, and cyclopenin, metabolites with antibiotic properties, but not the potent nephrotoxins xanthomegnin and viomellein or tremorgenic mycotoxins (e.g., penitrem A). The variety is also distinguished by conspicuously rough-walled conidia. Three additional new varieties which do not produce mycotoxins normally associated with their species are also reported: P. griseofulvum var. dipodomyicola var.nov. produced the antibiotically active compounds patulin and griseofulvin but not cyclopiazonic acid and roquefortine C; P. glandicola var. mononematosa var.nov. and P. glandicola var. confertum var.nov. did not produce roquefortine C, penitrem A, or patulin. Infrequently isolated strains of the species P. viridicatum and P. griseofulvum duplicated the mycotoxin profiles of the cultures ex type. It is suggested that the evolution of seed-caching behaviour in D. spectabilis may have guided the selection of less-toxic terverticillate penicillia as colonists in rodent seed caches.