Blast-Resistance Inheritance of Space-Induced Rice Lines and Their Genomic Polymorphism by Microsatellite Markers

To understand the resistance inheritance basis of space-induced rice lines to blast, and to probe mutants’ genomic DNA polymorphism compared with ground control by microsatellite markers, three space-induced lines were crossed with a highly susceptible variety LTH, and their F1 and F2 populations were inoculated by two representative blast isolates with broad pathogenicity to analyze their resistance inheritance basis. Meanwhile three mutant lines and the ground control were analyzed by 225 rice SSR (simple sequence repeat) primer pairs selected throughout the 12 chromosomes of whole rice genome, to scan the mutagenesis in genome of the mutant lines. The results indicated the blast-resistant genes harbored in these mutant lines were dominant. It was demonstrated that the resistance of mutant H1 to isolate GD0193 and GD3286 was controlled by a single gene, respectively; while mutants H2 and H3 were controlled by two pairs of major genes against isolate GD3286 and H2 showed complicated genetic mechanism to isolate GD0193. H3's resistance to isolate GD0193 was verified to be controlled by a single gene. According to the results of SSR analysis, three mutant lines showed different mutant rates as compared with the ground control, and the mutant rates also varied. Resistance genes can be induced from rice by space mutation, and different genomic variations were detected in blast-resistant lines.