玉米细胞分裂素反应调节因子基因的克隆与进化分析

在植物的生长发育过程中,细胞分裂素在调节细胞分裂和组织发育中起着非常重要的作用.研究表明细胞分裂素的信号转导是一种双组分信号转导途径,在这个系统中,由3种蛋白组成,分别是组氨酸激酶、磷酸转移蛋白和反应调控因子.利用已经克隆的玉米和水稻细胞分裂素反应调节因子基因,进行BLAST分析从玉米全基因组中获得候选ZmRR类型基因.然后设计全长基因引物,通过Trizol法提取玉米叶片总RNA,利用RT-PCR技术克隆出全长候选基因.序列分析表明所扩增序列含有完整的编码框,共编码156个氨基酸残基.序列比对分析其与ZmRR1-10基因具有较高的同源性,并命名为ZmRR11,系统进化树分析证实其属于A类细胞分裂素调控因子,并对所有ZmRR类型基因进行motif分析,共发现37个保守的motif.该基因的克隆和进化分析对阐明玉米双元信号传导体系具有重要的意义.     

甜瓜WRKY转录因子家族基因生物信息学分析

WRKY转录因子是一类重要的调控分子,在高等植物中以基因家族的形式存在。本研究以甜瓜(Cucumis melo L.)基因组数据为材料,利用生物信息学手段对WRKY转录因子家族成员、系统进化、基因分类、保守基序(motif)的保守性进行预测和分析。研究表明,甜瓜WRKY家族包含61个基因,其中13个含有2个WRKY结构域和C_2H_2锌指型结构归为第Ⅰ类,43个含有1个WRKY结构域和C_2H_2锌指型结构的归为第Ⅱ类,5个含有1个WRKY结构域和C2HC锌指型结构的归为第Ⅲ类。     

植物Dof基因家族功能研究进展

Dof(DNA-binding with one finger)蛋白是植物特有的一类转录因子,在植物生长发育过程中起着重要的作用。在其N-末端有一个52氨基酸残基组成的高度保守的C2-C2单锌指结构,称为Dof保守域,能够特异性的识别植物启动子序列中的AAAG/CTTT作用元件,从而激活或抑制植物基因的表达;其C-末端的转录调控结构域,氨基酸序列较为多变,不具有保守性,是Dof蛋白在植物中功能多样性的基础;同时Dof蛋白也具有和蛋白相互作用的功能。在过去的十几年里,大量的Dof基因被克隆鉴定或从基因组数据库中预测出来,Dof蛋白在植物生长发育中的作用也受到更多关注。本文就Dof转录因子的特点,各物种中已经报道的Dof转录因子的数目、系统进化关系和分类及其生物学功能的进展进行了综述。     

三浅裂野牵牛MADS-box基因家族全基因组鉴定与组织特异性表达分析

在甘薯近缘种三浅裂野牵牛(Ipomoea trifida)全基因组水平上对MADS-box基因家族进行鉴定和分析,结果表明,在三浅裂野牵牛基因组中,共鉴定到38个MADS-box(ItfMADS)成员。根据理化性质分析,各成员的氨基酸数目差异很大,有26个成员显碱性。亚细胞定位表明,在这些成员中有32个定位于细胞核。系统进化分析发现,ItfMADS家族可分为Ⅰ型和Ⅱ型2类,Ⅰ型包含9个成员,Ⅱ型包含29个成员。染色体定位分析发现,该38个ItfMADS成员不均匀地分布在三浅裂野牵牛基因组的12条染色体上,其中染色体11(Chr11)上的成员数最多(9个),而Chr12和Chr00仅有1个成员。结构域保守基序分析表明:各成员均含有MADS-box结构域,Ⅱ型的各成员还含有K结构域;motif 1和motif 3是ItfMADS蛋白的重要保守基序。基因结构分析表明,各成员中的内含子和外显子数量差异较大。启动子顺式作用元件分析发现,响应光的顺式作用元件最多。表达模式分析发现,ItfMADS基因在不同的组织中表达存在差异,且在不同胁迫下的表达量也不同,说明ItfMADS基因可能参与了胁迫响应。本研究为甘薯MADS-box基因的功能鉴定提供了参考,也为甘薯的分子育种奠定了基础。     

Dof转录因子在植物中的调控作用

DNA binding with one finger(Dof)蛋白是植物中特有的一类转录因子,自1993年在玉米中发现该转录因子到如今已有26年的历史。Dof蛋白只有一个由52个氨基酸组成的单锌指保守结构域,该结构域包含4个保守的半胱氨酸残基和一个二价锌离子,这两者都是Dof转录因子重要的组成部分,二者缺一不可,若半胱氨酸发生突变,或存在其他二价离子螯合剂都将会影响锌指结构的生成,进而使Dof蛋白不能与DNA结合,导致其丧失活性。半胱氨酸残基和Zn2+可以共价结合构成CX2CX21CX2C基序,此基序能够特异识别启动子中的AAAG(或CTTT)序列,从而激活或抑制靶基因的表达。Dof蛋白C-末端氨基酸序列的多变性导致该转录因子进化的多样性,从而在植物的生长发育过程中发挥着不同且重要的功能,如种子萌发、维管的发育和叶片极性、花和花粉发育、光周期反应、参与碳和氮的代谢、合成次生代谢产物、植物的逆境响应过程等。围绕着Dof转录因子的结构、系统进化关系、motif的组成和在植物中发挥的功能展开综述,以期为后续Dof转录因子的研究奠定相应的理论基础。     

胡萝卜中DcDofD1转录因子的克隆及其对非生物逆境胁迫的响应分析

Dof(DNA-binding with one finger)转录因子是植物特有的一类转录因子,该类转录因子在植物生长发育过程中起重要作用。本试验以胡萝卜黑田五寸和君川红为试验材料,分别从中克隆获得Dc Dof D1转录因子基因。采用生物信息学方法对Dc Dof D1转录因子氨基酸组成、理化性质、进化关系进行了分析。并利用实时定量PCR方法对Dc Dof D1基因在非生物胁迫下的表达量进行了分析。结果表明,黑田五寸和君川红中的Dc Dof D1转录因子具有明显的单锌指结构,保守域的氨基酸序列比较保守。进化分析显示,Dc Dof D1属于Dof家族的D1亚族。在胡萝卜黑田五寸和君川红中,Dc Dof D1基因对高温、低温、干旱、盐等非生物胁迫有响应。而不同胡萝卜材料中,Dc Dof D1基因对非生物逆境响应的强度和速度不同。     

甘薯基因组TCP转录因子鉴定与逆境胁迫表达分析

基于甘薯(Ipomoea batatas(L.)Lam.)全基因组序列,利用生物信息学方法鉴定筛选了全基因组中的TCP(teosinte branched1/cincinnata/proliferating cell factor)转录因子,并分析了甘薯苗期在蔓割病菌胁迫及块根储藏期低温胁迫下TCP基因的表达差异。结果显示,甘薯基因组中共有27个TCP转录因子,其中ClassⅠ13个、ClassⅡ(CIN)8个、ClassⅡ(CYC/TB1)6个。甘薯TCP以单个基因或基因簇的形式不均匀分布在15条染色体上,其中6对基因存在潜在复制关系。甘薯ClassⅡ(CYC/TB1)转录因子含有R结构域,其氨基酸序列较为保守。在TCP家族中共发现10个保守基序(motif),基序的氨基酸序列长度为15~60个,其中motif 1含有TCP结构域,motif 3含有R结构域,TCP转录因子的保守基序种类在组间存在一定差异。逆境胁迫下甘薯的转录组数据分析结果表明,TCP转录因子在苗期受蔓割病侵染后有2个差异表达基因;在块根储藏期受低温胁迫下有11个差异表达基因。     

Dof基因家族调节植物生长发育功能的研究进展

Dof（DNA binding with one finger）蛋白是一类植物特异性转录因子,通常含有200～400个氨基酸和2个主要结构域。该家族成员的N 末端为高度保守的单锌指Dof结构域,具有与DNA和蛋白质相互作用的双重功能,其C末端的氨基酸序列则较为多变,是Dof蛋白重要的特异转录调控结构域。研究表明,Dof蛋白作为转录激活物或阻遏物参与了多方面的植物生长发育过程。随着基因组测序技术的发展,已有大量的Dof基因从植物基因组数据库中鉴定出来。该文对近年来国内外有关Dof基因家族的结构特点、全基因组鉴定、蛋白互作以及生物学功能等方面的研究进展进行综述,以期为Dof转录因子的深入研究提供参考。     

水稻抗逆相关基因的分子进化分析

植物在进化过程中为了适应外界环境,已经具有一套完整的抵抗外界特殊环境的调控系统。但是,关于水稻抗逆相关基因的分子进化方面的研究还未见报道。文章通过Plant Tolerance Gene Database数据库,获得22个水稻抗逆相关基因。利用比较基因组学和生物信息学方法对水稻抗逆相关基因的进化动态进行研究,结果表明水稻抗逆相关基因在低等植物中比较保守;随着植物的不断进化和生存环境的改变,其基因数量也随之增加。具有相似抗性功能的基因往往具有相似的基因结构和基序(motif)结构。文章还发现4个保守motif 的存在：HRDXK、DXXSXG、LLPR和GXGXXG(X代表任意氨基酸)。在GSK1、RAN2抗逆基因中发现了3个特有的motif结构：GSK1特有的P-rich motif,RAN2特有的G-rich motif和E-rich motif。推测这些保守的motif结构与基因的抗逆功能密切相关。进化速率分析结果表明,尽管植物抗逆性相关基因在进化过程中受到较强的纯化选择作用,但是仍然有50%的抗逆性相关基因存在正选择位点。这些正选择位点的存在有可能为基因适应外界环境变化提供了重要的物质基础。     

甘蓝型油菜MADS-box基因家族的鉴定与系统进化分析

MADS-box基因家族参与调控开花时间、花器官分化、根系生长、分生组织分化、子房和配子发育、果实膨大及衰老等植物生长发育的重要过程。基于甘蓝型油菜(Brassica napus)基因组测序数据,利用生物信息学方法对甘蓝型油菜MADS-box基因家族进行鉴定和注释及基因结构与系统进化分析。结果显示,在甘蓝型油菜中鉴定出307个MADS-box基因家族成员,根据进化关系可将其分为两大类型,I型(M-type)包含α、β、γ三个亚家族,II型(MIKC-type)包括MIKCC和MIKC*两个亚家族,MIKCC可进一步分为13个小类;甘蓝型油菜A基因组染色体上分布的MADS-box基因多于C基因组。在基因结构上,MIKC-type亚家族基因序列普遍比M-type长且含有较多的外显子;M-type亚家族蛋白序列中的motif数量为2–5个,MIKC-type亚家族蛋白序列中平均含有7个motif。拟南芥(Arabidopsis thaliana)与甘蓝型油菜MADS-box基因共线性分析结果显示,全基因组复制事件对MADS-box基因家族尤其是MIKC亚家族的扩张起重要作用;MIKC亚家族基因在进化过程中受到的选择压力约为M-type的2倍,这表明MIKC-type亚家族在进化过程中被选择性保留。     

Genome-Wide Identification and Analysis of Expression Profiles of Maize Mitogen-Activated Protein Kinase Kinase Kinase

Mitogen-activated protein kinase (MAPK) cascades are highly conserved signal transduction model in animals, yeast and plants. Plant MAPK cascades have been implicated in development and stress responses. Although MAPKKKs have been investigated in several plant species including Arabidopsis and rice, no systematic analysis has been conducted in maize. In this study, we performed a bioinformatics analysis of the entire maize genome and identified 74 MAPKKK genes. Phylogenetic analyses of MAPKKKs from maize, rice and Arabidopsis have classified them into three subgroups, which included Raf, ZIK and MEKK. Evolutionary relationships within subfamilies were also supported by exon-intron organizations and the conserved protein motifs. Further expression analysis of the MAPKKKs in microarray databases revealed that MAPKKKs were involved in important signaling pathways in maize different organs and developmental stages. Our genomics analysis of maize MAPKKK genes provides important information for evolutionary and functional characterization of this family in maize.     

In silico analysis of PHB gene family in maize

Prohibitins (PHBs) are highly conserved proteins in species ranging from prokaryotes to eukaryotes. Plant PHBs have been implicated in various cellular processes including development, senescence and stress responses. Although PHBs have been investigated in several plant species including Arabidopsis and tobacco, no systematic gene family analysis has been carried in maize. In the present study, 16 putative PHB genes have been identified. Analysis of the conserved protein motifs and gene structures has revealed high levels of conservation within the phylogenetic subgroups. Published microarray database showed that most maize PHB genes exhibited different expression levels in different tissues and developmental stages. Cis-elements analysis showed that ZmPHB2 and ZmPHB12 may play important roles in plant development. Taken together, we provide a comprehensive bioinformatics analysis of the PHB gene family in maize genome and our data provide an important foundation for further functional study of this gene family in maize.     

Genome-wide identification and characterisation of F-box family in maize

F-box-containing proteins, as the key components of the protein degradation machinery, are widely distributed in higher plants and are considered as one of the largest known families of regulatory proteins. The F-box protein family plays a crucial role in plant growth and development and in response to biotic and abiotic stresses. However, systematic analysis of the F-box family in maize (Zea mays) has not been reported yet. In this paper, we identified and characterised the maize F-box genes in a genome-wide scale, including phylogenetic analysis, chromosome distribution, gene structure, promoter analysis and gene expression profiles. A total of 359 F-box genes were identified and divided into 15 subgroups by phylogenetic analysis. The F-box domain was relatively conserved, whereas additional motifs outside the F-box domain may indicate the functional diversification of maize F-box genes. These genes were unevenly distributed in ten maize chromosomes, suggesting that they expanded in the maize genome because of tandem and segmental duplication events. The expression profiles suggested that the maize F-box genes had temporal and spatial expression patterns. Putative cis-acting regulatory DNA elements involved in abiotic stresses were observed in maize F-box gene promoters. The gene expression profiles under abiotic stresses also suggested that some genes participated in stress responsive pathways. Furthermore, ten genes were chosen for quantitative real-time PCR analysis under drought stress and the results were consistent with the microarray data. This study has produced a comparative genomics analysis of the maize ZmFBX gene family that can be used in further studies to uncover their roles in maize growth and development.     

Genome-wide analysis of WOX gene family in rice, sorghum, maize, Arabidopsis and poplar

WUSCHEL-related homeobox(WOX)genes form a large gene family specifically expressed in plants.They are known to play important roles in regulating the development of plant tissues and organs by determining cell fate.Recent available whole genome sequences allow us to do more comprehensive phylogenetic analysis of the WOX genes in plants.In the present study,we identified 11 and 21 WOXs from sorghum(Sorghum bicolor)and maize(Zea mays),respectively.The 72 WOX genes from rice(Oryza sativa),sorghum,maize,Arabidopsis(Arabidopsis thaliana)and poplar(Populus trichocarpa)were grouped into three well supported clades with nine subgroups according to the amino acid sequences of their homodomains.Their phylogenetic relationship was also supported by the observation of the motifs outside the homodomain.We observed the variation of duplication events among the nine sub-groups between monocots and eudicots,for instance,more gene duplication events of WOXs within subgroup A for monocots,while,less for dicots in this subgroup.Furthermore,we observed the conserved intron/exon structural patterns of WOX genes in rice,sorghum and Arabidopsis.In addition,WUS(Wuschel)-box and EAR(the ERF-associated amphiphilic repression)-like motif were observed to be conserved among several WOX subgroups in these five plants.Comparative analysis of expression patterns of WOX genes in rice and Arabidopsis suggest that the WOX genes play conserved and various roles in plants.This work provides insights into the evolution of the WOX gene family and is useful for future research.