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


1 Phytopathology Department, Bu-Ali Sina University, Hamedan, Iran

2 Assistant Professor of Microbial GeneticsPhytopathology Department, Bu-Ali Sina University, Hamedan, Iran


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.