Nuclear DNA content of 11 fungal species in Glomales

The nuclear DNA content of 11 species of Glomales was evaluated by flow cytometry after DAPI staining relative to Gigaspora margarita, which was used as internal standard. The nuclear DNA content of this species was calibrated by propidium iodide staining relative to chicken red blood cells. A correction was applied when the difference in AT content of the DNA was significant between a sample and the standard. A single unimodal peak of fluorescence was observed for nuclei from the quiescent spores of the 11 fungal species studied. It was considered that this peak corresponded to the amount of DNA in the genome of each species. Important interspecific variations in DNA content per nucleus (1- to 8-fold) were observed among four species of the genus Scutellospora.