DEDIKARYOTIZATION OF THE SHIITAKE MUSHROOM, LENTINULA EDODES BY THE PROTOPLAST REGENERATION METHOD

The present study was carried out to investigate the applicability and usefulness of the protoplast isolation and regeneration method as a n ew technique for artificially dedikaryotizing Lentinula edodes dikaryo ns. When protoplasts derived from dikaryans were incubated in a regene ration agar medium at 25 degrees C, about 11% of them individually sta rted regeneration into hyphae within 3 days and formed visible colonie s, varying in size, after 7 days of incubation. By isolating preferent ially smaller colonies out of these visible colonies, it was found tha t neohaplonts could be obtained at the high frequencies of 40-92% in e very dikaryon sampled and that the two-component nuclear types appeare d. These neohaplonts showed considerable variation of mycelial growth rates. However, robust neohaplonts exhibited no apparent change in bio logical properties such as colony morphology, and electophoretic zymog rams of esterase and malate dehydrogenase, suggesting that they might retain the original genetic traits. From these results, it is conclude d that the protoplast regeneration method for dedikaryotizing L. edode s dikaryons is more useful than previous methods such as the physical procedure and chemical treatment.