An investigate on the effects of photoperiod, aging and culture media onvegetative growth and sporulation of rice blast pathogen pyricularia oryzae

Pyricularia oryzae (Tel. Magnaporthegrisea) is currently used as a fungal model for plantmicrobe interaction studies as well as an indicative model for anticancer drug discovery. The present study introduces the optimal condition in which P. oryzae grows and sporulates best on common culture media. We have considered three fungal culture media, i.e. PDA, PCA and WA, based on which P. oryzae sporulation inducers like rice polish, rice extract or rice leaf segments could be added, and evaluated both for vegetative growth and sporulation. Three light regimens, i.e. continuous light, 16.8 hr light/darkness, and continuous darkness were applied in combination with nine synthetic culture media. Mycelial growth was measured after 11 days, but sporulation was tracked on the 10th, 20th, and 30th day after incubation at 26ºC. The findings indicate that PDA culture medium could provide the best medium for P. oryzae vegetative growth, regardless of light condition. However, P. oryzae could sporulate when light was provided either continuously or at intervals. A combination of 16.8 hr light/darkness intervals and adding rice materials to culture media could induce P. oryzae for a better sporulation. RPCA can be used as the best culture medium for P. oryzae in order to obtain a high number of conidia under light alterations. Moreover, aging increases the total number of conidia.