Characterizing of Rice Blast Lesion Mimic

When plants are infected by plant pathogens, typical disease symptom termed lesion, appears in compatible interaction. Whereas, in incompatible interactions, only small speck of lesions are visible on the leaf surfaces. Hypersensitive response (HR) of plant which is the result of infection by incompatible pathogens, is a well known defense response inducing rapid cell death resulting in complete resistance. However, some rice mutants show spontaneous disease symptoms during the growth stages without interaction with pathogens. We investigated the spontaneous cell death mutant called Blast Lesion Mimic(BLM) generated by EMS mutation, on the relationship with the hypersensitive response as well as resistant characteristics. Accumulation of phenolic compounds were detected around the lesions as lesions develop on leaf surface. Activation of PR gene was detected before the lesion appeared, and that result indicates the defense-related response are started earlier than lesion formation. The BLM mutant showed resistant response to inoculation of Magnaporthe grisea KJ201 with which the wild type Hwacheong is totally susceptible. Informations on the formation of spontaneous lesions and detail analysis of lesion mimic mutants and related genes are very limited to date. It is really important to understand the phenomenon of the defense-related lesion formation for developing resistant cultivar for rice blast pathogens