Induction of low sporulating-UV mutant of oyster mushroom with high content of vitamin D 2

Oyster mushrooms comprise some most popular edible mushrooms due to their favorable organoleptic and medicinal properties, vigorous growth and undemanding cultivation conditions. One of the major problems in cultivating oyster mushrooms for workers is the abundant production of spores. The inhalation of these spores induces allergic responses. Furthermore, vitamin D deficiency is an ever-increasing problem in human nutrition and health. The present study was initiated to use ultra violet irradiation (UV) to obtain a new mutant of Pleurotus columbinus with improved characters and to solve the previous problems. Mycelial plugs of the actively growing parent were exposed to UV-C for different periods from ten to thirty minutes. Twenty minutes irradiation period showed the best mycelial growth (R20) and was selected for further evaluations. The fresh fruiting bodies of mutant R20 had lower gills number by 32%, lower strigmata by half and reduced spore content by 72% per each cm 3 compared to parent (R0). Moreover, the fruiting bodies of R20 posses higher ability for vitamin D 2 production after UV-C irradiation for different periods. The best vitamin D 2 production was achieved in R20 after 30 minutes exposure (121.95 µg/g fresh mushrooms) compared to parent (60.87 µg/g fresh mushrooms). These new acquired characters of the mutant R20 make it better for commercial production and more attractive for human consumption.