| 摘要: |
| 【目的】研究胡杨质膜Na+/H+逆向转运蛋白（SOS1）通过H2O2信号途径对盐胁迫的感知和适应作用。【方法】克隆胡杨质膜SOS1基因（PeSOS1），并将其转化到拟南芥中，比较野生型和转PeSOS1基因拟南芥在100 mmol/L NaCl胁迫下的萌发率，根长，干质量，K+、Na+和Ca2+含量，活体植株根尖离子流（K+、Na+和H+）的流动情况，H2O2的产生和抗氧化酶活性的变化以及抑制剂对根尖离子流的影响，分析100 mmol/L NaCl胁迫下异源表达PeSOS1基因拟南芥与野生型拟南芥耐盐性的差异。【结果】在NaCl胁迫下，转PeSOS1基因拟南芥株系的萌发率、根长和干质量明显高于野生型拟南芥；转PeSOS1基因拟南芥K+和Ca2+含量也高于野生型拟南芥，而Na+含量较野生型拟南芥低。100 mmol/L NaCl处理后，转PeSOS1基因拟南芥中K+和Na+的平衡（K+/Na+值）与NaCl胁迫前相比下降幅度较小。转PeSOS1基因植株在NaCl胁迫下能更快地产生H2O2，并使抗氧化酶保持较高的活性。SOS1抑制剂阿米洛利（Amiloride）对NaCl胁迫下野生型和转基因拟南芥根尖离子流的变化有明显影响，用质膜NADPH氧化酶抑制剂DPI（抑制H2O2的产生）处理后，转PeSOS1基因拟南芥根尖K+内流减弱，Na+外流和H+内流增强，植株维持K+和Na+平衡的能力减弱。【结论】在拟南芥中异源表达PeSOS1基因可促进H2O2快速产生，维持了SOS1 mRNA的稳定性，调控了K+和Na+平衡，并激活了抗氧化防御系统，因而显著提高了其耐盐性。 |
| 关键词: 胡杨 盐胁迫 转基因拟南芥 质膜Na+/H+逆向转运蛋白（SOS1） H2O2信号 K+/Na+平衡 离子流 |
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| 基金项目:国家自然科学基金项目(31270654，31170570)；教育部科学技术研究项目(113013A)；北京市自然科学基金项目(6112017)；中央高校基本科研业务费专项(JC2011-2，TD-2012-04)；北京市优秀博士学位论文指导教师专项(YB20081002201)；高等学校学科创新引智计划项目(111 Project，B13007) |
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| Modulation of H2O2 signaling in salt-stressed Arabidopsis by PeSOS1 |
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WANG Mei-juan,WANG Yang,SHEN Ze-dan,et al
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| Abstract: |
| 【Objective】This study aimed to investigate the role of PeSOS1 in salt sensing and adaption through H2O2 signaling.【Method】Plasma Membrane (PM) Na+/H+ antiporter gene PeSOS1 of Populus euphratica was cloned and introduced to Arabidopsis thaliana.Then differences in salt tolerance between wild-type and PeSOS1-transgenic Arabidopsis plants were illustrated by comparing germination,root length,biomass,contents of K+,Na+ and Ca2+,fluxes of root K+,Na+ and H+,H2O2 production,antioxidant enzyme activity and effects of inhibitor on ion fluxes of homozygous seedlings under 100 mmol/L NaCl salt stress.【Result】Compared to wild-type,PeSOS1-transgenic Arabidopsis plants had higher germination rate,root length,and biomass under NaCl stress.PeSOS1-transgenic Arabidopsis plants also had higher contents of K+ and Ca2+ but lower content of Na+.Transgenic plants exhibited lower ratio of Na+/H+ antiport compared to wild-type.In roots of transgenic Arabidopsis,H2O2 production was more rapidly than wild-type when plants were subjected to NaCl stress and the activities of the antioxidant enzymes were higher.Transgenic plants were unable to remain K+/Na+ homeostasis when salt-induced H2O2 production was inhibited by diphenylene iodonium (DPI),an inhibitor of NADPH oxidase.【Conclusion】PeSOS1 increased salt tolerance through rapid H2O2 production,which maintained the stability of SOS1 mRNA,controlled K+/Na+ homeostasis and triggered antioxidant defense in Arabidopsis. |
| Key words: Populus euphratica salt stress transgenic Arabidopsis PM Na+/H+ antiporter（SOS1） H2O2 signaling K+/Na+ homeostasis ion flux |
