摘要
The spread of tissue necrosis leads to plant death. We isolated 18 lethal necrotic mutants induced in rice (Oryza sativa L.) by gamma-irradiation. The necrotic lethality among the 18 mutants was controlled by single recessive genes designated necrotic lethality1 (nec1) to nec18. These mutants display pale-green leaves from the third-leaf stage and leaf-tip necrosis, which spreads to the whole plant, killing it. Genetic mapping and histochemical analysis of the lethal necrotic mutants were conducted. At least four independent loci on chromosomes 2 and 4 controlled necrotic lethality. Therefore, the genetic causes of lethal necrosis vary among mutant stocks. Histochemical analysis at 12 days after sowing showed that H2O2 accumulated in the necrotic parts of leaves, and that cell death occurred throughout the leaf. Mutants for early necrotic lethality (<24 days to lethality) were characterized by the rapid spread of H2O2 accumulation throughout the third leaf. Mutants for late necrotic lethality (>35 days to lethality) were characterized by the incomplete spread of H2O2 accumulation within the third leaf.
The spread of tissue necrosis leads to plant death. We isolated 18 lethal necrotic mutants induced in rice (Oryza sativa L.) by gamma-irradiation. The necrotic lethality among the 18 mutants was controlled by single recessive genes designated necrotic lethality1 (nec1) to nec18. These mutants display pale-green leaves from the third-leaf stage and leaf-tip necrosis, which spreads to the whole plant, killing it. Genetic mapping and histochemical analysis of the lethal necrotic mutants were conducted. At least four independent loci on chromosomes 2 and 4 controlled necrotic lethality. Therefore, the genetic causes of lethal necrosis vary among mutant stocks. Histochemical analysis at 12 days after sowing showed that H2O2 accumulated in the necrotic parts of leaves, and that cell death occurred throughout the leaf. Mutants for early necrotic lethality (<24 days to lethality) were characterized by the rapid spread of H2O2 accumulation throughout the third leaf. Mutants for late necrotic lethality (>35 days to lethality) were characterized by the incomplete spread of H2O2 accumulation within the third leaf.
