NO和H2O2互作在水稻根系响应镉胁迫中的作用及机制

Nitric oxide (NO) and hydrogen peroxide (H2O2) are two kinds of unique signaling molecules in plant. The crosstalk between NO and H2O2 play key roles to modulate plant growth and development and mediate the reception, signal transduction and responses to biotic and many abiotic stresses. However, the signal transduction pathway and relationship between NO and H2O2 in plants under Cd stress are still unclear. we have investigated the resouce of NO, metabolism rule, and its relationship with Cd-tolerance for rice seedling under Cd stress. In this project, using pharmacology, plant physiology and biochemistry, cytochemistry technique, etc, the effects of crosstalk between nitric oxide and hydrogen peroxide on root tip growth, the contents of nitric oxide and hydrogen peroxide, the component of cell wall, oxidation protection, the activity of mitogen-activated protein kinases, cadmium accumulation and tolerance will be inverstigated to ellucidate the relationship, roles and mechanisms of crosstalk between nitric oxide and hydrogen peroxide in rice under cadmium stress and the role of mitogen-activated protein kinases and the relationship among nitric oxide, hydrogen peroxide and mitogen-activated protein kinases in rice root response to cadmium stress. Based on these theoretical understandings, it is very important and useful to reveal the mechanism of cadmium toxicity and tolerance from the view of signal transduction. Simultaneously, these results could provide an important technical support to improve the stress tolerance by chemical regulation in rice production.

一氧化氮(NO)和过氧化氢(H2O2)均是普遍存在于植物体内的信号分子，二者之间互作共同参与植物生长发育的调控、对生物和非生物胁迫的感受、信号传导与适应过程。但是，关于植物镉胁迫响应过程中NO和H2O2信号传导途径及NO和H2O2间的相互关系却知之甚少，许多问题尚不清楚。本项目申请者在已明确了镉胁迫下水稻体内NO代谢特征及其作用的基础上，拟通过药理学、生理生化、细胞化学等技术，分析NO和H2O2互作对镉胁迫下水稻根尖生长、NO和H2O2含量动态变化、细胞壁组分及相关酶、抗氧化防护、MAPK活性、镉积累和耐性的影响，揭示NO和H2O2在水稻根系响应镉胁迫中的相互关系和调控水稻镉积累和耐性的机制，探明MAPK在镉胁迫响应信号转导过程中的作用及其与NO和H2O2之间的关系，旨在从信号转导方面揭示植物耐镉机制，也为今后在生产实践中应用信号物质调控植物耐镉性提供重要的理论依据和技术支持。

一氧化氮(NO)和过氧化氢(H2O2)均是普遍存在于植物体内的信号分子，二者之间互作共同参与植物生长发育的调控、对生物和非生物胁迫的感受、信号传导与适应过程。本项目研究了H2O2在水稻根系应对镉胁迫中的作用，分析了NO和H2O2互作对镉胁迫下水稻根尖生长、NO和H2O2含量动态变化、细胞壁组分及相关酶、抗氧化防护、MAPK活性、镉积累和耐性的影响。通过研究表明一定浓度的H2O2通过提高抗氧化酶系统、增强细胞壁的结构及膜的完整性，降低根中镉含量，促进水稻种子萌发和根系生长。DMTU和c-PTIO均可降低NO和H2O2在提高水稻根系耐性中的作用，在此过程中二者表现出一定的信号互作，且NO信号产生早于H2O2；PD98059明显加重镉对水稻根系的抑制，降低SNP和H2O2的作用，说明MAPK在H2O2和NO提高水稻根系耐镉性中起着重要作用。研究结果为从信号转导方面揭示植物耐镉机制提供重要的理论依据和技术支持。