剖析耐盐基因及其调控的分子途径是培育水稻耐盐材料的前提和基础。鉴于AP2转录因子是调控植物生长发育的重要因子，采用人工小RNA干扰技术及田间筛选方法，我们鉴定到多个AP2转录因子在水稻耐盐性中的调控功能。其中转录抑制子IDS1的干扰株系表现明显的耐盐性；生理生化检测表明IDS1负调控渗透调节物质的积累；基因表达分析表明IDS1抑制了大量胁迫相关基因的表达，且IDS1可结合渗透调节蛋白LEA3基因启动子，表明IDS1可能通过负影响渗透调节物质的积累调控水稻的耐盐性。本项目拟在以上研究基础上，采用功能缺失突变体及过表达材料剖析IDS1调控水稻的耐盐性功能、转录抑制活性；进一步结合转录组表达谱分析，剖析IDS1调控水稻耐盐性的靶基因；通过剖析IDS1与靶基因启动子结合的作用位点及靶基因启动子的顺式元件，解析IDS1调控水稻耐盐性的生化和遗传基础，以期为作物抗逆性分子育种提供新的思路和有用的基因。

Soil salinization, which has been becoming environmental resource constraint of the sustainable development of the world irrigated agriculture, affects the yield of the crop. Mining of more salt tolerance genes and recovering the regulation network of salt response, are the prerequisite and basis of the breeding of new rice salt tolerance cultivated varieties. AP2 transcription factors are plant-specific transcription factors which are composed by many family members. Studies in recent years recover that this transcription factor family play important roles in regulation of plant growth and development, as well as response to phytohormones and biotic/abiotic stress. EAR (ethylene-responsive element binding factor-associated amphiphilic repression) motif is a conserved amphipathic leucine-rich sequence which endows the transcription repression activity to a transcription factor. EAR motif plays important roles in stress response and stress-related genes expression. We analysized 374 EAR-motif-containing ERF transcription factors and found 57 of them are differentially expressed under salt stress. By using amiRNA interferance knock-down technique and land-field screening, several AP2 transcription factors were identified as regulators of rice salt tolerance. The knock-down lines of IDS1, one of the transcriptional repressor of AP2 transcription factor family, showed significant salt tolerance. All the physiological and biochemical data indicated that IDS1 negatively regulates the accumulation of osmotic adjustment substances. Gene expression analysis demonstrated that expression of many stress-related genes were suppressed by IDS1. We also found that IDS1 can directly bind the promoter region of LEA3, which encodes an osmotic regulation protein, indicating that IDS1 regulates rice salt tolerance maybe by adjusting the accumulation of osmotic adjustment substances. Based on these experiments, by confirming the function of IDS1 in rice salt tolerance by using mutant and overexpression lines, analyzing the transcriptional repressor activity of IDS1, finding the downstream target genes of salt response and mapping the active amino acids residue sites and cis-element of LEA3; this project will analysis the molecular pathway of the IDS1 on regulation of the rice salt tolerance, reveal relationship of IDS1 and salt stress response to elucidate the molecular basis of the IDS1 on regulation of the rice salt tolerance, and provide the useful genes and new thoughts to the molecular breeding of the crop stress tolerance.