Study Of Epigenetic Mechanisms Of JMJ706 Involving In Rice Oxidative Stress Response

As a sessile organism, it is very important for plants to sense environment changes and rapidly adapt to it for its optimal growth. Epigenetic modifications, which are independent of DNA sequence changes, are involved in gene expression regulation. Epigenetic modifications often include DNA methylation, histone modifications, chromatin remodelings, s RNA and histone variants. More and more reports indicate that epigenetic modifications were involved in stress reponsive gene regulation such as drought, salt, cold, ABA, heat, and pathogens. We characterized the function of histone demethylase gene JMJ706, which has been cloned by our research group, responding to stress in this study. It was found that JMJ706 was responsive to drought salt ABA and oxidative stresses through analyzing rice abiotic responses profiles from public database and our results. Then the physiological and biochemical, genetic and molecular biology experiments were further conducted to verify that the molecule mechanism of JMJ706 involving in rice oxidative stress, and main results were as follows,1. JMJ706 responded to salt, drought, ABA, paraquat and H2O2 stress and it was responsive to paraquat significantly. Compared to wild type, jmj706 mutant plants showed more resistant to paraquat at the young seedling stage, but there was no difference in germination process and four-leaf stage.2. Compared with wild type, total chlorophyll content in aboveground parts was higher and chloroplast structure remained relatively intact in 5-d jmj706 seedlings after 0.5 μM paraquat treatment.3. After the paraquat stress, enzyme activity of SOD and total ascorbic acid content increased significantly in jmj706 plants. And our results also showed that JMJ706 cannot inhibit paraquat transport regulated by Os PAR1.4. Two-week-old jmj706 seedling showed more resistance to H2O2 through reducing accumulation of H2O2 in the first complete leaf, while there was no clear phenotypes difference between 5-d jmj706 and wild type seedling when treated with H2O2.5. ROS scavenging enzyme relative genes were induced rapidly by paraquat and H2O2 stress.6. JMJ706 increased sensitivity to oxidative stress at rice seedling stage by regulating Os CSD1 and Os CSD5 expression indrectly.