Mitochondrial mutation impairs cytoplasmic male sterility rice in response to H2O2 stress

Cytoplasmic male sterility (CMS) is a phenomenon widely observed in various plant species characterized with disrupted anther development caused by mitochondrial mutation. CMS is becoming a model system for the investigations of nucleus–cytoplasmic interaction. To reveal the possible effects of CMS genes on plant growth in adverse environment, plant development and biochemical characters of mitochondria from Honglian (HL)-CMS line Yuetai A and maintainer Yuetai B treated with H2O2 were analyzed. Results showed that 40–60 mM H2O2 significantly inhibits rice seedling development and growth. When treated with H2O2, ATP content and mitochondrial membrane potential in Yuetai A decreased significantly faster than those of Yuetai B. These biochemical changes were accompanied by the severe nuclear DNA fragmentation and the release of mitochondrial cytochrome c in the leaf cells of Yuetai A. In addition, the antioxidative enzyme activities and mitochondrial electron transfer chain complexes were significantly down-regulated. Disturbance of the biochemical indexes indicate that HL-CMS line is more susceptible to H2O2 stress than the maintainer line, the deleterious effects caused by the CMS-related ORFH79 peptide compromises the adaptability of HL-CMS line to the adverse environment.

► 40–60 mM H2O2 lead to different response of CMS and maintainer lines.
► More susceptibility of CMS rice relative to maintainer line to H2O2.
► PCD biochemical indexes can be used as indicator for rice stress response.