Differential biochemical response of rice (Oryza sativa L.) genotypes against rice blast (Magnaporthe oryzae)

The disease-free (control) and blast infected leaf samples of 11 rice genotypes were evaluated for activity profile of defense-related and antioxidative enzymes. The amplification genomic DNA with two SSR markers RM124 and RM224 were also performed for identification of blast resistance and susceptible genotypes. The activity of chitinase, PAL and beta-glucosidase of post pathogen-infected leaf samples increased significantly in all rice genotypes, thought the increase was comparable less in to blast susceptible genotypes Chimansal and EK-70. The activity of antioxidative enzymes was comparatively higher in the infected leaf of blast resistant genotypes recording highest increase in NLR-20104 and KJT-5. The activity of defense-related and antioxidative enzymes in the disease-free leaf samples differed among the genotypes and was even higher in the two blast susceptible genotypes. RM144 and RM224 SSR primers clearly amplified in blast resistant KJT-5, NLR-20104, KJT-2, Tetep genotypes whereas RM144 missing in susceptible Chimansal but prominently present in susceptible genotype EK-70. This study revealed that higher level of induction of defense-related and antioxidative enzymes and presence of specific amplified fragments with RM144 and RM224 could be useful for screening the resistant and susceptible rice genotypes against Magnaporthe oryzae.