摘要
AtNHX2基因是拟南芥NHX基因家族的一员 ,编码了一种液泡膜中的Na+ /H+ 反向运输体并对拟南芥的耐盐能力起着重要的作用 .采用PCR扩增的方法克隆了拟南芥AtNHX2基因启始密码子上游约 2 8kb的DNA片段 ,并将其克隆到植物表达载体pCAMBIA130 1 1中 ,通过基因枪轰击洋葱表皮瞬时表达的方法 ,初步检测启动子的活性 .将重组质粒pCAMBIA130 1 1/AtNHX2promoter转化拟南芥并筛选纯合子 .AtNHX2promoter GUS分析显示AtNHX2在所有的组织中均有表达 ,包括根尖 .在保卫细胞中检测到了强烈的GUS表达 ,这一结果表明 ,AtNHX2对特殊细胞的pH调控和K+ 自身稳定方面起着重要的作用 .AtNHX2启动子的活性可被NaCl抑制 ,并且抑制的强度和NaCl的浓度成正相关 .30 0mmol/LKCl处理可增强启动子的活性 ,说明NaCl和KCl是在转录水平上调控AtNHX2的表达 .在老叶中GUS活性比在新叶中GUS活性强 ,这说明了AtNHX2优先将有毒的离子积累在老叶中 ,从而有利于植物的正常发育 .在根毛细胞中也观测到了强烈的GUS活性 ,这就暗示了AtNHX2在扩大的液泡中储存Na+ .
The Arabidops thaliana AtNHX2 gene is one member of the Arabidopsis NHX Na(+)/H(+) antiporter gene family and play an important role in salt tolerance. A sequence-analyzed 2.8 kb DNA fragment on upstream of ATG start codon of AtNHX2 gene was cloned into pCAMBIA1301-1. The promoter activity was detected by transient expression in onion epidermis. The reconstructed vector pCAMBIA1301-1/ AtNHX2 promoter was transformed into Arabidopsis thaliana by Floral Dip method. AtNHX2 promoter-GUS analysis in transgenic Arabidopsis showed that AtNHX2 was expressed in all tissues. Strong GUS expression was detected in guard cells suggesting the possibility that it is involved in stomatal regulation. AtNHX2 promoter activity was decreased by NaCl and up-regulated by KCl, demonstrating that NaCl and KCl regulation to AtNHX2 expression occurs at the transcriptional level. GUS activity in old leaves was higher than in new leaves, which reveals a role of AtNHX2 in salt tolerance. Strong GUS activity in root hair cells was observed. It suggests that AtNHX2 may play an important role in partitioning of Na(+) into the enlarged vacuoles of root hair cells.
出处
《生物化学与生物物理进展》
SCIE
CAS
CSCD
北大核心
2004年第12期1114-1118,共5页
Progress In Biochemistry and Biophysics
基金
国家科技攻关西部科技行动项目资助 ( 2 0 0 1BA90 1A3 2 )~~
