Abstract
Protoplasts were prepared for axenic suspension cultures of the wheat stem rust fungus Puccinia graminis f. sp. tritici, race 126 Anz-5,6,7,11. Protoplats were released in 3 hr from 3- to 7-day-old mycelia with a mixture of Novozym 234 and cellulase (5 mg each/ml) osmotically stablized by 0.8 M MgSO4. Protoplast regeneration was detected microscopically within 10 hr after incubation in a nutrient medium containing 0.5 M sorbitol, and colonies usually were visible after a further 3 days of growth. The regeneration frequency ranged from 19 to 39%.