摘要：

前期组学分析发现,水稻ERF转录因子OsDERF1响应水分胁迫,为探究该转录因子在水稻水氮耦合下调控水分利用效率提升的机制,进一步分析其在局部根系水分胁迫(PRD)与不同氮素形态耦合条件下的表达模式,以期为水氮耦合下OsDERF1调控水稻水分利用机制的解析提供理论依据。以广东省常规稻品种美香占2号为试验材料,采用3种水分处理(CK、PRD、PEG)与3种铵态氮/硝态氮配比(A100/N0、A0/N100、A50/N50)进行协同处理,分析OsDERF1在水稻根、茎、叶3种组织中的表达模式;通过生物信息学方法解析OsDERF1编码蛋白的结构特征、理化性质等。结果表明,OsDERF1基因编码区全长为732 bp,编码243个氨基酸,其编码蛋白的分子质量为25.97 ku,理论等电点为4.77,不稳定系数为54.36,亲水性平均系数为-0.475,综上特征该蛋白为不稳定亲水蛋白。亚细胞定位结果显示,OsDERF1定位于细胞核,且蛋白序列中含有一个AP2保守结构域,表明OsDERF1属于核转录因子。qRT-PCR结果显示:OsDERF1在水稻根、茎、叶中均有表达,但存在组织表达差异——根部相对表达量显著高于叶片和茎部。进一步分析不同处理对各组织表达的影响发现:根部在PRD-L与A50/N50耦合处理下相对表达量最高。综上所述,OsDERF1转录因子在水稻根部组织中,以PRD与A50/N50氮素形态耦合处理下的相对表达量最高,且胁迫条件下根部的表达量显著高于非胁迫根。据此推测,OsDERF1可能通过根部组织响应水分与氮素双重信号,进而参与水稻干旱胁迫下的分子调控机制。

关键词: 水稻, 局部根系水分胁迫(PRD), 氮素形态, 转录因子OsDERF1

Abstract:

Previous omics analysis revealed that the ERF transcription factor OsDERF1 in rice responds to water stress.To explore the mechanism by which this transcription factor regulates the improvement of water use efficiency under water and nitrogen coupling in rice,this study further analyzed its expression pattern under partial root-zone drying(PRD)and coupling conditions of different nitrogen forms,aiming to provide a theoretical basis for understanding the mechanism of OsDERF1 regulating water use in rice under water and nitrogen coupling.The conventional rice variety Meixiangzhan 2 from Guangdong Province was used as the experimental material.Three water treatments(CK,PRD,PEG)and three ammonium/nitrate nitrogen ratios(A100/N0,A0/N100,A50/N50)were applied in a combined manner.The expression pattern of OsDERF1 in the root,stem,and leaf tissues of rice was analyzed.The structural characteristics and physicochemical properties of the OsDERF1 encoded protein were analyzed by bioinformatics methods.The results showed that the full length of the OsDERF1 coding region was 732 bp,encoding 243 amino acids.The molecular weight of the encoded protein was 25.97 ku,the theoretical isoelectric point was 4.77,the instability index was 54.36,and the average hydrophilicity coefficient was -0.475.Based on these characteristics,the protein was an unstable hydrophilic protein.Subcellular localization results showed that OsDERF1 was located in the nucleus,and the protein sequence contained an AP2 conserved domain,indicating that OsDERF1 was a nuclear transcription factor.qRT-PCR results showed that OsDERF1 was expressed in the root,stem,and leaf tissues of rice,but there were tissue expression differences:the relative expression level in the root was significantly higher than that in the leaf and stem.Further analysis of the effects of different treatments on the expression in each tissue revealed that the relative expression level in the root was the highest under PRD-L and A50/N50 coupling treatment.In summary,the relative expression level of the OsDERF1 transcription factor in the root tissue of rice was the highest under PRD and A50/N50 nitrogen form coupling treatment,and the expression level under stress conditions in the root was significantly higher than that in the non-stressed root.Based on this,it is speculated that OsDERF1 may respond to dual signals of water and nitrogen through the root tissue and participate in the molecular regulation mechanism of rice under drought stress.

Key words: Rice, Partial root-zone drying(PRD), Nitrogen form, Transcription factor OsDERF1

中图分类号: 

• S511稻