为获得烟草AREB/ABF(ABA响应元件结合蛋白/ABRE结合因子)家族转录因子基因序列,进一步提高烟草的抗渗透胁迫能力,通过同源比对和RT-PCR技术,从烟草品种红花大金元中克隆到烟草AREB/ABF家族转录因子NtABF1(GenBank登录号为KF736849),NtAB...为获得烟草AREB/ABF(ABA响应元件结合蛋白/ABRE结合因子)家族转录因子基因序列,进一步提高烟草的抗渗透胁迫能力,通过同源比对和RT-PCR技术,从烟草品种红花大金元中克隆到烟草AREB/ABF家族转录因子NtABF1(GenBank登录号为KF736849),NtABF2(GenBank登录号为KF736850)基因编码序列,并进一步利用生物信息学分析软件对这两个转录因子的蛋白理化性质、高级结构和生物学功能进行了预测。结果表明:NtABF1基因开放阅读框(Open Reading Frame,ORF)长999 bp,编码332个氨基酸,蛋白分子量36.45 kDa,等电点9.04;NtABF2基因ORF长1305 bp,编码433个氨基酸,蛋白分子量46.92kDa,等电点9.35。NtABF1和NtABF2均为含有BRLZ(Basic Region and Leucine Zipper)保守结构域的亲水蛋白,不含信号肽与跨膜结构。其高级结构均以α螺旋和无规则卷曲为主,β转角和延伸链含量较少。在亚细胞水平上,NtABF1和NtABF2均定位于细胞核。磷酸化位点分析表明,两蛋白均含有丝氨酸,苏氨酸和酪氨酸等激酶识别位点。进化分析和多序列比对结果表明,NtABF1与AtAREB3的进化关系最近,序列相似性达54.49%;NtABF2与SlAREB1,StABF1和StABF的亲缘关系较近,序列相似性分别为83.63%,83.52%和83%。功能预测结果显示,NtABF1和NtABF2均为转录调控因子。展开更多
非生物胁迫严重影响植物的生长发育及农作物的产量。植物激素脱落酸(ABA,abscisic acid)是植物响应非生物胁迫的重要信号分子,其介导的ABA信号途径在植物应答非生物胁迫过程中发挥关键作用,其中ABF(ABA-responsive element binding fact...非生物胁迫严重影响植物的生长发育及农作物的产量。植物激素脱落酸(ABA,abscisic acid)是植物响应非生物胁迫的重要信号分子,其介导的ABA信号途径在植物应答非生物胁迫过程中发挥关键作用,其中ABF(ABA-responsive element binding factors)转录因子在ABA信号途径中扮演着重要的角色。ABF转录因子是一类特异识别ABA响应元件(ABRE,ABA-responsive element)的碱性亮氨酸拉链蛋白,属于bZIP家族中的A亚族。它含有5个高度保守的结构域,C1、C2、C3、C4以及可以结合DNA序列的bZIP区域,这些保守结构域能够被蔗糖非酵解型蛋白激酶2(SnRK2,sucrose nonfermenting-1 related protein kinase 2)和钙依赖蛋白激酶(CDPK,calcium-dependent protein kinase)等多种蛋白激酶磷酸化,进而激活ABF蛋白的转录活性,使其参与ABA和逆境胁迫的调控表达。近年来,有较多研究发现不同物种中的ABF类转录因子在植物响应非生物胁迫的过程中具有重要作用。本文综述了ABF转录因子的结构特征及识别的顺式作用元件如G-ABRE、C-ABRE、"偶联元件3"(CE3,coupling element 3)等、调控修饰途径及其在盐、干旱、低温等非生物胁迫应答中的作用,并对未来ABF转录因子的研究方向进行展望,为通过调控ABF转录因子从而培育优良抗逆作物品种提供研究思路。展开更多
Abscisic acid （ABA） is a major plant hormone that plays an important role in responses to abiotic stresses. The ABA-responsive element binding protein/ABRE-binding factor （AREB/ABF） gene subfamily contains crucial...Abscisic acid （ABA） is a major plant hormone that plays an important role in responses to abiotic stresses. The ABA-responsive element binding protein/ABRE-binding factor （AREB/ABF） gene subfamily contains crucial transcription factors in the ABA-mediated signaling pathway. In this study, a total of 14 putative AREB/ABF members were identified in the Populus trichocarpa Torr. ＆ Gray. genome using five AREB/ABF amino acid sequences from Arabidopsis thaliana L. as probes. The 14 putative Populus subfamily members showed high protein similarities, especially in the basic leucine zipper （bZIP） domain region. A neighbor-joining analysis combined with gene structure data revealed homology among the 14 genes. The expression patterns of the Populus AREB/ABF subfamily suggested that the most abundant transcripts of 11 genes occurred in leaf tissues, while two genes were most transcribed in root tissues. Significantly, eight Populus AREB/ABF gene members were upregulated after treatment with 100 t^M exogenous ABA, while the other six members were downregulated. We identified the expression profiles of the subfamily members in Populus tissues and elucidated different response patterns of Populus AREB/ABF members to ABA stress. This study provided insight into the roles of Populus AREB/ABF homologues in plant response to abiotic stresses.展开更多
Chlorophyll （Chl） degradation is an integral process of leaf senescence, and NYE1/SGR1 has been demonstrated as a key regulator of Chl catabolism in diverse plant species. In this study, using yeast one-hybrid scree...Chlorophyll （Chl） degradation is an integral process of leaf senescence, and NYE1/SGR1 has been demonstrated as a key regulator of Chl catabolism in diverse plant species. In this study, using yeast one-hybrid screening, we identified three abscisic acid （ABA）-responsive element （ABRE）-binding transcription factors, ABF2 （AREB1）, ABF3, and ABF4 （AREB2）, as the putative binding proteins of the NYE1 promoter. Through the transactivation analysis, electrophoretic mobility shift assay, and chromatin immunoprecipitation, we demonstrated that ABF2, ABF3, and ABF4 directly bound to and activated the NYE1 promoter in vitro and in vivo. ABA is a positive regulator of leaf senescence, and exogenously applied ABA can accelerate Chl degradation. The triple mutant of the ABFs, abf2abf3abf4, as well as two ABA-insensitive mutants, abil-1 and snrk2.2/2.3/2.6, exhibited stay-green phenotypes after ABA treatment, along with decreased induction of NYE1 and NYE2 expression. In contrast, overexpression of ABF4 accelerated Chl degradation upon ABA treatment. Interestingly, ABF2/3/4 could also activate the expression of two Chl catabolic enzyme genes, PAO and NYCl, by directly binding to their promoters. In addition, abf2abf3abf4 exhibited a functional stay-green phenotype, and senescence-associated genes （SAGs）, such as SAG29 （SWEET15）, might be directly regulated by the ABFs. Taken together, our results suggest that ABF2, ABF3, and ABF4 likely act as key regulators in mediating ABA-triggered Chl degradation and leaf senescence in general in Arabidopsis.展开更多
文摘为获得烟草AREB/ABF(ABA响应元件结合蛋白/ABRE结合因子)家族转录因子基因序列,进一步提高烟草的抗渗透胁迫能力,通过同源比对和RT-PCR技术,从烟草品种红花大金元中克隆到烟草AREB/ABF家族转录因子NtABF1(GenBank登录号为KF736849),NtABF2(GenBank登录号为KF736850)基因编码序列,并进一步利用生物信息学分析软件对这两个转录因子的蛋白理化性质、高级结构和生物学功能进行了预测。结果表明:NtABF1基因开放阅读框(Open Reading Frame,ORF)长999 bp,编码332个氨基酸,蛋白分子量36.45 kDa,等电点9.04;NtABF2基因ORF长1305 bp,编码433个氨基酸,蛋白分子量46.92kDa,等电点9.35。NtABF1和NtABF2均为含有BRLZ(Basic Region and Leucine Zipper)保守结构域的亲水蛋白,不含信号肽与跨膜结构。其高级结构均以α螺旋和无规则卷曲为主,β转角和延伸链含量较少。在亚细胞水平上,NtABF1和NtABF2均定位于细胞核。磷酸化位点分析表明,两蛋白均含有丝氨酸,苏氨酸和酪氨酸等激酶识别位点。进化分析和多序列比对结果表明,NtABF1与AtAREB3的进化关系最近,序列相似性达54.49%;NtABF2与SlAREB1,StABF1和StABF的亲缘关系较近,序列相似性分别为83.63%,83.52%和83%。功能预测结果显示,NtABF1和NtABF2均为转录调控因子。
文摘非生物胁迫严重影响植物的生长发育及农作物的产量。植物激素脱落酸(ABA,abscisic acid)是植物响应非生物胁迫的重要信号分子,其介导的ABA信号途径在植物应答非生物胁迫过程中发挥关键作用,其中ABF(ABA-responsive element binding factors)转录因子在ABA信号途径中扮演着重要的角色。ABF转录因子是一类特异识别ABA响应元件(ABRE,ABA-responsive element)的碱性亮氨酸拉链蛋白,属于bZIP家族中的A亚族。它含有5个高度保守的结构域,C1、C2、C3、C4以及可以结合DNA序列的bZIP区域,这些保守结构域能够被蔗糖非酵解型蛋白激酶2(SnRK2,sucrose nonfermenting-1 related protein kinase 2)和钙依赖蛋白激酶(CDPK,calcium-dependent protein kinase)等多种蛋白激酶磷酸化,进而激活ABF蛋白的转录活性,使其参与ABA和逆境胁迫的调控表达。近年来,有较多研究发现不同物种中的ABF类转录因子在植物响应非生物胁迫的过程中具有重要作用。本文综述了ABF转录因子的结构特征及识别的顺式作用元件如G-ABRE、C-ABRE、"偶联元件3"(CE3,coupling element 3)等、调控修饰途径及其在盐、干旱、低温等非生物胁迫应答中的作用,并对未来ABF转录因子的研究方向进行展望,为通过调控ABF转录因子从而培育优良抗逆作物品种提供研究思路。
基金supported by the Major State Basic Research Development Program (2012CB114505)the National Natural Science Foundation of China (31170631)the National High-tech Research and Development Program (2011AA100201) of China
文摘Abscisic acid （ABA） is a major plant hormone that plays an important role in responses to abiotic stresses. The ABA-responsive element binding protein/ABRE-binding factor （AREB/ABF） gene subfamily contains crucial transcription factors in the ABA-mediated signaling pathway. In this study, a total of 14 putative AREB/ABF members were identified in the Populus trichocarpa Torr. ＆ Gray. genome using five AREB/ABF amino acid sequences from Arabidopsis thaliana L. as probes. The 14 putative Populus subfamily members showed high protein similarities, especially in the basic leucine zipper （bZIP） domain region. A neighbor-joining analysis combined with gene structure data revealed homology among the 14 genes. The expression patterns of the Populus AREB/ABF subfamily suggested that the most abundant transcripts of 11 genes occurred in leaf tissues, while two genes were most transcribed in root tissues. Significantly, eight Populus AREB/ABF gene members were upregulated after treatment with 100 t^M exogenous ABA, while the other six members were downregulated. We identified the expression profiles of the subfamily members in Populus tissues and elucidated different response patterns of Populus AREB/ABF members to ABA stress. This study provided insight into the roles of Populus AREB/ABF homologues in plant response to abiotic stresses.
文摘Chlorophyll （Chl） degradation is an integral process of leaf senescence, and NYE1/SGR1 has been demonstrated as a key regulator of Chl catabolism in diverse plant species. In this study, using yeast one-hybrid screening, we identified three abscisic acid （ABA）-responsive element （ABRE）-binding transcription factors, ABF2 （AREB1）, ABF3, and ABF4 （AREB2）, as the putative binding proteins of the NYE1 promoter. Through the transactivation analysis, electrophoretic mobility shift assay, and chromatin immunoprecipitation, we demonstrated that ABF2, ABF3, and ABF4 directly bound to and activated the NYE1 promoter in vitro and in vivo. ABA is a positive regulator of leaf senescence, and exogenously applied ABA can accelerate Chl degradation. The triple mutant of the ABFs, abf2abf3abf4, as well as two ABA-insensitive mutants, abil-1 and snrk2.2/2.3/2.6, exhibited stay-green phenotypes after ABA treatment, along with decreased induction of NYE1 and NYE2 expression. In contrast, overexpression of ABF4 accelerated Chl degradation upon ABA treatment. Interestingly, ABF2/3/4 could also activate the expression of two Chl catabolic enzyme genes, PAO and NYCl, by directly binding to their promoters. In addition, abf2abf3abf4 exhibited a functional stay-green phenotype, and senescence-associated genes （SAGs）, such as SAG29 （SWEET15）, might be directly regulated by the ABFs. Taken together, our results suggest that ABF2, ABF3, and ABF4 likely act as key regulators in mediating ABA-triggered Chl degradation and leaf senescence in general in Arabidopsis.
