小麦胁迫响应转录因子基因TaSNAC1的克隆与表达分析  

Cloning and Expression Analysis of Wheat Stress-responsive Transcription Factor Gene TaSNAC1

作　　者：单丽伟[1] 宋鹏[1] 刘夏燕[1] 张超[1] 卫晓彬[1] 韩兆雪[1] 郭蔼光[1] 范三红[1] 

机构地区：[1]旱区作物逆境生物学国家重点实验室,西北农林科技大学生命科学学院,杨凌712100

出　　处：《农业生物技术学报》2012年第5期489-496,共8页Journal of Agricultural Biotechnology

基　　金：中央高校基本科研业务费专项(No.QN2009070);国家转基因专项(No.2008ZX08002-003)

摘　　要：摘要胁迫响应NAC转录因子参与植物非生物胁迫过程，过表达水稻（Oryzasativa）SNAC1可显著提高植株耐旱、耐冷和抗盐性。本研究同源克隆了小麦（Tricum aestivurn）TaSNAC1基因（GenBank登录号No．JN621240），分析了其表达产物的亚细胞定位，并利用实时定量RT．PCR分析了其在不同组织、PEG和NaC1胁迫下的表达。该基因包含一个内含子，编码329个氨基酸残基的蛋白产物。TaSNAC1与其他禾本科植物SNAC1蛋白高度相似，其与大麦（Hordeumv ulgare）、二穗短柄草（Brachypodium distachyon）、水稻、玉米（Zeamays）和高粱（Sorghum bicolor）SNACl序列相似性依次为97．3％、86．3％、81．1％、79．1％和79．2％。TaSNAC1可能以二聚体形式存在，包含核定位信号和典型的NAM结构域，100-107位的“wKATGxDK100-107”核心基序处于一段β折叠中，其弯曲产生的凹面可能直接参与DNA结合。瞬时转化拟南芥似rabidopsis thaliana）叶肉细胞原生质体的实验表明，TaSNAC1特异定位于细胞核中。盐胁迫条件下，叶和根中TaSNAC1的表达量均升高，且表达模式相似，但根中响应更显著；PEG胁迫下，根中TaSNAC1对胁迫的响应较快且幅度较大，而叶中响应较慢且幅度较小。研究结果提示，TaSNAC1参与小麦的非生物胁迫响应过程，在耐旱、抗盐遗传改良中具有潜在应用价值。Stress responsive NAC transcription factors involve in plant abiotic stress tolerance. Overexpression of SNA C1 significantly enhances drought, cold and salinity resistance in transgenic rice（Oryza sativa）. In this study, TaSNA C1 was obtained from common wheat （Triticum aestivum） by homology-based cloning, its sub-celluar localization was analyzed, and its expression patterns in different tissues and under PEG or salt stress were investigated by quantitative RT-PCR. The cDNA of amplified TaSNA C1 including complete CDS was 1 076 bp in size, and the gDNA was 1 222 bp including a 146 bp intron （GenBank accession No. JN621240）. TaSNAC1 encoded a protein with 329 amino acids, which showed 97.3%, 86.3%, 81.1%, 79.1%and 79.2% identity with SNAC1 of barley （Hordeum vulgare）, false brome （Brachupodium distachyon）, rice, maize （Zea mays） and sorghum （Sorghum bicolor）, respectively. Results of phylogenetic analysis showed that TaSNAC 1 was different from other wheat NAC transcription factors, it was clustered into a separate clade with other grass stress-responsive NAC. Structure prediction showed that TaSNAC 1 might form a dimer, including a untypical nuclear localization signal （NLS） and a typical no apical meristem （NAM） domain. The core motif ＂WKATGXDK100-107＂ was located in a 13 sheet, which formed a concave surface and confered the ability of DNA binding. Based on transient expression assay using Arabidopsis thaliana mesophyll protoplasts, we found TaSNAC1 localized in the nucleus specifically. The expression levels of TaSNA C1 in both leaf and root wereincreased significantly in similar pattern during the application of high salt, and the increase in root was more dramatic （upto -60 folds in root and-10 folds in leaf）. Under PEG stress, the transcripts of TaSNA C1 were elevated quickly and sharply in root, but the change in leaf was delayed and the amplitude was decreased （about 15 folds in root and 6 folds in leaf）. These data suggest that TaSNA C1 plays a vital role

关 键 词：小麦 TaSNAC1 亚细胞定位 非生物胁迫 表达模式 

分 类 号：Q943.2[生物学—植物学]