中文摘要：

目的：克隆拟南芥AtNCED2基因启动子区域序列,并分析其组织器官特异性及对外界刺激的响应。方法：通过PCR从拟南芥基因组中克隆AtNCED2基因5’侧翼2295bp启动子区域序列（AtNCED2p）,并进行生物信息学分析。构建AtNCED2p驱动GUS的植物双元表达载体pAtNCED2p：：GUS,通过根癌农杆菌介导法将其转化野生型拟南芥,检测转基因植株中GUS表达的组织器官特异性。结果：该启动子序列中存在TATA-box、CAAT-box、根器官特异性元件、ABA响应元件、低温响应元件、昼夜节律响应元件等顺式作用元件。GUS活性主要集中在转基因拟南芥根尖及侧根发生部位。外源ABA处理的转基因植株根中GUS活性为174.8nmol4-MU min-1mg-1蛋白,明显高于对照值91.7nmol 4-MU min-1mg-1蛋白。结论：AtNCED2基因可能在根的生长和发育中起作用,且外源ABA处理增强其在根中的表达。

英文摘要：

Objective： To clone the promoter region sequence of AtNCED2 gene from Arabidopsis genome,and analyze its organ specificity and response to stimuli.Method： Genomic DNA was isolated and purified from Arabidopsis（Arabidopsis thaliana L.） plants through the SDS method.Based on the reported sequence in GenBank（accession No.AL161548） DNA database,a pair of specific primers were designed and synthesized to amplify the 5＇ flanking 2 295 bp sequence of AtNCED2 gene from Arabidopsis genome.The 2295-bp promoter region sequence of 5＇ upstream of initial codon of AtNCED2 gene was confirmed by BLASTn program of NCBI,and was put into the search engine of the database of plant cis-acting elements to search for cis-acting elements responsive to development signal and various environmental stimuli.The binary vector harboring the promoter sequence of AtNCED2 fused with GUS gene originated from pCAMBIA1301 was further constructed and introduced into wild type Arabidopsis through Agrobacterium-mediated transformation.The resulting transgenic plants after hygromycin screening and PCR characterization were assayed for the GUS activity spatially.Result： Several important cis-acting elements,including TATA-box,CAAT-box,root organ-specific elements,ABA-responsive element（ABRE）,low-temperature-responsive element（LTRE）,and circadian-responsive element were existed in the promoter region sequence.GUS activity was dominantly localized in root tips and lateral root initiation sites of transgenic Arabidopsis.The GUS activity in exogenous ABA-treated roots of transgenic Arabidopsis was 174.8 nmol 4-MU min-1 mg-1 protein,significantly higher than that in control roots,which only reached 91.7 nmol 4-MU min-1 mg-1 protein.Conclusion： AtNCED2 gene may play an important role in root growth and development.The expression AtNCED2 gene in Arabidopsis roots was significantly increased by exogenous ABA application.