treatment. Under red light, the formation of blast lesions with
white, collapsed tissues (which signifies a susceptible response
from rice) was significantly inhibited, and the formation of necrotic
lesions was increased, as compared to white and natural light
treatment (Fig. 1b). In our study, there was no difference in mycelial
growth on PDA medium or in infection behaviors (such as spore
germination, appressorium formation, or infection hypha formation) in onion cells in response toM. oryzae depending on the type
of light treatment (data not shown). These results indicate that red
light stimulates the rice defense system by converting a compatible
interaction into an incompatible one, as demonstrated by the
decrease in blast lesions and increase in necrotic spots. In similar
findings,Guo et al. (1993)reported that race-specific resistance of
rice against Xanthomonas campestrispv.