东南景天捕光叶绿素a/b结合蛋白基因SaLhcb2的分离及功能  

Characterization of a light-harvesting chlorophyll a/b binding protein (LHCB) gene,Sa Lhcb2,in Sedum alfredii

作　　者：李真[1,2,3] 刘明英[2,3] 韩小娇[2,3] 乔桂荣[2,3] 蒋晶[2,3] 邢世岩[1] 卓仁英[2,3] 

机构地区：[1]山东农业大学林学院,山东泰安271000 [2]中国林业科学研究院亚热带林业研究所,浙江富阳311400 [3]中国林业科学研究院林木遗传育种国家重点实验室,北京100091

出　　处：《浙江农林大学学报》2014年第6期838-846,共9页Journal of Zhejiang A&F University

基　　金：国家自然科学基金资助项目(31200465)

摘　　要：LHCB基因对植物适应各种环境胁迫的过程中起着重要作用。序列分析显示:东南景天Sedum alfredii的Sa Lhcb2基因全长929 bp,其中开放阅读框(ORF)为798 bp,含有1个74 bp的内含子。通过蛋白序列比对,Sa Lhcb2基因编码的蛋白与多种植物的蛋白序列同源性都很高(92%以上)。分析400μmol·L-1镉离子(Cd2+),铜离子(Cu2+)和铅离子(Pb2+)胁迫处理后的东南景天,结果显示:镉处理后Sa Lhcb2基因在茎、叶中表达量快速上升(12.0h内),根中表达量到48.0 h后才上调。铜处理后0.5 h根中表达显著上调,胁迫6.0 h后茎中表达量显著上调,随后一直降低,叶片中该基因表达量一直较低。铅处理后,根中表达量降低,96.0 h左右比对照略微上调,而茎中96.0 h内表达量相比对照都上调,叶片中96.0 h内都降低。研究结果表明:Sa Lhcb2与东南景天的镉、铜、铅胁迫抗性有密切的相关性。The light-harvesting chlorophyll a/b binding protein （LHCB） gene plays an important role in plants adapting to various environments.Sedum alfredii is a new Zn/Cd hyper-accumulator and whether LHCB in this interesting species was related to the heavy-metal tolerance interested us a lot.In the present study,we isolated a cDNA using homologous cloning and designated it as SaLhcb2 which encoded a light-harvesting chlorophyll a/b binding protein in Sedum alfredii.A prelimary sequence analysis was conducted and homologous comparison was also performed using MegAlign.In order to identify the gene expression profiles of SaLhcb2 response to heavy-metal stress,seedlmgs of Sedum alfredii were treated by 400 μmol· L-1 Cd^2＋,Cu^2＋,and Pb^2＋ stresses with those cultured in water as a control.Roots,stems and leaves were dissected and promptly frozen in liquid nitrogen for RNA extraction and the followed real-time PCR.Sequence analysis showed that the coding sequence of SaLhcb2 was 929 bp and the open reading frame was 798 bp.The deduced protein,SaLHCB2,consisted of 266 amino acids and had a high homology （above 92%） with LHCB2 of other plants via homologous comparison.For the Cd^2＋,Cu^2＋,and Pb^2＋ stress treatments,the level of SaL hcb2 was elevated dramatically in stems and leaves within 12.0 h.However,with the Cd^2＋ treatment,the expression of SaLhcb2 in roots did not display a tendency of up-regulation until 48.0 h.For the Cu^2＋ treatment,in roots,the expression of SaLhcb2 showed a prompt response of up-regulation at 0.5 h and then decreased weirdly.With the Pb^2＋ treatment,the expression of SaLhcb2 in roots displayed a profile of down-regulation except the point of 96.0 h.Based on the above findings,it could be concluded that the expression of SaLhcb2 in Sedum alfredi was influenced by heavy-metal treatment and may function in the process of plants combating heavy-metal stress.

关 键 词：植物学 镉、铜、铅 叶绿素a/b结合蛋白(LHCB) 荧光定量PCR 东南景天 

分 类 号：S722.3[农业科学—林木遗传育种]