The DNA content of the mycelial nuclei of rust fungi grown on artificial media

Abstract

The nuclear condition of vegetative mycelia of several races of Puccinia recondita f. sp. tritici, P. graminis f. sp. tritici, P. coronata f. sp. avenae, and Gymnosporangium asiaticum was determined by propidium iodide staining. Cultures originating from the uredinial stage of P. recondita f. sp. tritici, from the uredinial stage of P. coronata f. sp. avenae, and from the spermogonial stage of Gymnosporangium asiaticum were all predominantly monokaryotic. The dikaryotic condition was observed in two cultures from the uredinial stage of P. graminis f. sp. tritici and P. recondita f. sp. tritici, in one culture from the aecial stage of Gy. asiaticum, and in germ tubes from uredospores of Puccinia spp. Measurements of the DNA content indicated monokaryotic diploid cultures and dikaryotic haploid cultures in the Puccinia species. In Gy. asiaticum, all nuclei were haploid, but the nuclei had twice as much DNA as haploid nuclei in the Puccinia spp.