调控小麦春化发育特性的相关基因研究进展

小麦春化发育过程主要受VRN1、VRN2、VRN3等基因的调控。对小麦春化基因的研究进展及其互作关系进行了综述,指出小麦VRN1基因经低温诱导可以加速植株茎尖由营养生长向生殖生长转变,VRN1的3个部分同源基因的等位变异是小麦春化发育特性差异的主要决定因子;VRN2基因是一个开花抑制因子,其核心作用结构域的单碱基突变会使基因失去功能;VRN3基因被长日照诱导,可促进植株开花,基因的等位差异对小麦开花时间早晚有显著影响。VRN1、VRN2、VRN3 3个主要春化相关基因之间的互作共同调控小麦开花的春化响应途径。     

The wheat VRN2 gene is a flowering repressor down-regulated by vernalization

Plants with a winter growth habit flower earlier when exposed for several weeks to cold temperatures, a process called vernalization. We report here the positional cloning of the wheat vernalization gene VRN2, a dominant repressor of flowering that is down-regulated by vernalization. Loss of function of VRN2, whether by natural mutations or deletions, resulted in spring lines, which do not require vernalization to flower. Reduction of the RNA level of VRN2 by RNA interference accelerated the flowering time of transgenic winter-wheat plants by more than a month.     

Quantitative modulation of polycomb silencing underlies natural variation in vernalization

Arabidopsis thaliana accessions have adapted to growth in a wide range of climates. Variation in flowering and alignment of vernalization response with winter length are central to this adaptation. Vernalization involves the epigenetic silencing of the floral repressor FLC via a conserved Polycomb (PRC2) mechanism involving trimethylation of Lys(27) on histone H3 (H3K27me3). We found that variation for response to winter length maps to cis polymorphism within FLC. A rare combination of four polymorphisms localized around the nucleation region of a PHD-Polycomb complex determines a need for longer cold. Chromatin immunoprecipitation experiments indicate that these polymorphisms influence the accumulation of H3K27me3 in Arabidopsis accession Lov-1, both at the nucleation site and over the gene body. Quantitative modulation of chromatin silencing through cis variation may be a general mechanism contributing to evolutionary change.     

Vernalization-mediated epigenetic silencing by a long intronic noncoding RNA

Vernalization is an environmentally-induced epigenetic switch in which winter cold triggers epigenetic silencing of floral repressors and thus provides competence to flower in spring. In Arabidopsis, winter cold triggers enrichment of tri-methylated histone H3 Lys(27) at chromatin of the floral repressor, FLOWERING LOCUS C (FLC), and results in epigenetically stable repression of FLC. This epigenetic change is mediated by an evolutionarily conserved repressive complex, polycomb repressive complex 2 (PRC2). Here, we show that a long intronic noncoding RNA [termed COLD ASSISTED INTRONIC NONCODING RNA (COLDAIR)] is required for the vernalization-mediated epigenetic repression of FLC. COLDAIR physically associates with a component of PRC2 and targets PRC2 to FLC. Our results show that COLDAIR is required for establishing stable repressive chromatin at FLC through its interaction with PRC2.     

木本果树开花相关基因的研究进展

开花是植物从营养生长向生殖生长的转变过程。拟南芥中存在多条调控开花时间的信号途径如光周期途径、春化途径、赤霉素途径和自动途径等。与草本植物相比,木本植物成花调控研究进展较缓慢。本文综述了木本果树中开花综合基因,即综合不同成花调控途径信号的关键基因,如CO、FLC、SVP、FT、LFY、TFL、AP1、SOC1等的研究进展,以期为进一步探索木本植物成花的分子调控机制提供参考。     

萝卜属抽薹开花相关基因FLC的预测及分析

以控制拟南芥春化途径的关键基因FLC全长CDS为参考序列,在萝卜属(Raphanus) EST数据库中进行BLASTN检索,得到具备Score≥100、E value≤10-10和coverage ≥70%条件的70条萝卜ESTs作为候选的拟南芥FLC基因的同源ESTs,并进行序列聚类拼接、注释及分析。结果显示: 在普通萝卜和野生萝卜中各发现两个旁系同源基因(RsFLCa和RsFLCb及RrFLCa和RrFLCb)。RFLCs与拟南芥FLC间在核酸水平上的一致性为787%～869%;RFLCs旁系同源基因间的一致性为759%～934%;RFLCs与芸薹属FLC直系同源基因间的一致性绝大多数维持在85%以上,且高于与拟南芥直系同源基因间的一致性。系统进化分析发现,与白菜、甘蓝及甘蓝型油菜中FLC多拷贝产生的机制可能类似,萝卜属FLC基因的多拷贝现象可能也是伴随萝卜基因组的多倍化而产生的。     

不同生态型拟南芥FLC基因的序列分析

[目的]研究拟南芥春化作用相关基因FLC的序列。[方法]对拟南芥自然群体的春化反应进行QTL分析,发现拟南芥5号染色体上有一个与开花有关的QTL,再运用序列分析确定它与FLC基因的同源性。[结果]意大利拟南芥与瑞典拟南芥在第27、461、501、638、738、884位碱基上不同。但密码子编码的第9、167、246个氨基酸由于密码子的简并性,编码的蛋白质均相同。[结论]拟南芥具有丰富的遗传多样性,由于FLC基因序列长度高度保守、碱基变异位点丰富密码子的简并性,它们均编码同一种氨基酸,对拟南芥生长没有影响。     

不同生态型拟南芥FLC基因的序列分析

[目的]对拟南芥春化作用相关基因FLC的序列分析。[方法]先期经过对拟南芥自然群体的春化反应的QTL分析,发现拟南芥5号染色体上有一个与开花有关的QTL,本实验就是运用序列分析确定它与FLC基因是否具有同源性。[结果]意大利拟南芥与瑞典拟南芥在第27位、第461位、第501位、第638位、第738位、第884位碱基上不同。虽然这些碱基有所不同,但是密码子编码出来的第9个氨基酸、第167个氨基酸、第246个氨基酸,由于密码子的简并性,编码的蛋白质均相同。[结论]拟南芥具有丰富的遗传多样性,其FLC基因序列长度高度保守、碱基变异位点丰富密码子的简并性它们均编码同一种氨基酸对拟南芥生长没有影响。这表明拟南芥的基因序列会受到环境的影响。     

Diversity of Growth Habits and Their Association with VRN Allele of 81 American Wheat Lines

Eighty-one wheat accessions including 50 southern regional performance nursery （SRPN） lines and 31 northern regional performance nursery （NRPN） lines from the United States were tested to evaluate the growth habit by chilling treatments and to estimate the VRN allele variation with 19 pairs of published VRN primers. Two spring wheat accessions and 44 semi-spring wheat accessions were confirmed based on their chilling days＇ requirement and polymorphism was found at VRN loci. The Vrn-A1 allele had the highest frequency in the RPN accessions and VA1-CAPs markers identified growth habit of RPN lines. No polymorphism was found at the VRN3 loci and some polymorphism at the region of promoter and the first intron of VRN1 was not always consistent to growth habit in the wheat RPN accessions. The existence of variation in VRN alleles suggested that singly using the dominant Vrn allele is possible to extend the diversity of wheat accessions and improve their adaption to different environments in autumn-sowing region. This information will be useful for the cultivars exploitation and wheat breeding program.     

DNA markers of the vernalization gene FRIGIDA in Brassica crops

Locus- and genome-specific markers of the FRIGIDA gene have been developed for mapping studies, for establishing the link between FRIGIDA and quantitative loci for floral transition and for introgression breeding of oil-seed rape, in particular, for such traits as time to flower and earliness. Keywords: Brassica, FRIGIDA, earliness, floral transition, introgression breeding, vernalization     

Diversity of Growth Habits and Their Association with VRN Allele of 81 American Wheat Lines

Eighty-one wheat accessions including 50 southern regional performance nursery (SRPN) lines and 31 northern regional performance nursery (NRPN) lines from the United States were tested to evaluate the growth habit by chilling treatments and to estimate the VRN allele variation with 19 pairs of published VRN primers. Two spring wheat accessions and 44 semi-spring wheat accessions were confirmed based on their chilling days' requirement and polymorphism was found at VRN loci. The Vrn-A1 allele had the highest frequency in the RPN accessions and VA1-CAPs markers identified growth habit of RPN lines. No polymorphism was found at the VRN3 loci and some polymorphism at the region of promoter and the first intron of VRN1 was not always consistent to growth habit in the wheat RPN accessions. The existence of variation in VRN alleles suggested that singly using the dominant Vrn allele is possible to extend the diversity of wheat accessions and improve their adaption to different environments in autumn-sowing region. This information will be useful for the cultivars exploitation and wheat breeding program.     

植物SOC1/AGL20基因研究进展

SOC1（SUPPRESSOR OF OVEREXPRESSION OF CO1）/AGL20（AGAMOUS-LIKE 20）是MADS-box家族一员,在植物开花过程中起着重要的调控作用,它能够整合来自光周期途径、春化途径、自主开花途径和赤霉素途径中的信号,并与其他基因相互作用共同调节植物的开花时间以及花的类型和花分生组织。目前已经证明SOC1基因的过表达可以促进植物提前开花,而soc1突变体则会表现出晚花的表型。相关研究也显示,SOC1在植物开花之外的其他生命活动中也起着重要作用。本研究主要对SOC1及其同源基因在植物开花和其他生理活动中的功能以及SOC1基因的表达调节等研究进展进行综述,通过对30种植物的SOC1同源基因序列进行聚类分析,发现SOC1基因的同源性基本反映了物种间的亲缘关系,最后对该基因的研究前景提出展望,为以后SOC1及其同源基因的相关研究提供一定的参考。图3表1参42     

植物SDC1/AGL20基因研究进展

SOC1（SUPPRESSOR OF 0VEREXPRESSION OF CO1）／AGL20（AGAMOUS—LIKE20）是MADS-box家族一员,在植物开花过程中起着重要的调控作用,它能够整合来自光周期途径、春化途径、自主开花途径和赤霉素途径中的信号,并与其他基因相互作用共同调节植物的开花时间以及花的类型和花分生组织。目前已经证明SOC1基因的过表达可以促进植物提前开花,而SOC1突变体则会表现出晚花的表型。相关研究也显示,SOC1在植物开花之外的其他生命活动中也起着重要作用。本研究主要对SOC1及其同源基因在植物开花和其他生理活动中的功能以及SOC1基因的表达调节等研究进展进行综述,通过对30种植物的SOC1同源基因序列进行聚类分析,发现SOC1基因的同源性基本反映了物种间的亲缘关系,最后对该基因的研究前景提出展望,为以后SOC1及其同源基因的相关研究提供一定的参考。     

低温春化过程中萝卜幼苗生长点的生理生化变化

采用常规方法和酶联免疫吸附法(ELISA)分别测定了耐抽薹和不耐抽薹两个萝卜品种低温处理(春化)过程中顶端生长点的可溶性蛋白等生化指标和赤霉素(GAs)等激素含量的变化。结果表明,低温处理过程中,抽薹性差异较大的两个品种可溶性蛋白、游离氨基酸、可溶性糖含量变化趋势基本一致。可溶性蛋白、游离氨基酸含量总体表现为逐渐升高的趋势,而可溶性糖含量则呈下降趋势。耐抽薹的萝卜品种长春大型,其可溶性蛋白和可溶性糖含量明显低于短叶十三,游离氨基酸含量则相反。两品种赤霉素(GAs)、生长素(IAA)的含量在花芽分化开始时均有较明显的峰值,在处理后期又出现另一明显峰值。     

植物开花的分子调控机理研究

植物开花是遗传因子和环境因素协同调控的复杂过程。在拟南芥中,植物开花途径主要有春化促进途径、光周期促进途径、自主开花途径及依赖于赤霉素的途径等。根据近年来的研究进展,综述了植物开花的分子调控机理。     

改变冬小麦为春小麦的研究

该项研究表明,用不同日数春化处理和连续春播的方法,经过3—4代,可将冬小麦改变为遗传上稳定的春小麦。从阿芙乐尔、高加索和五十周年三个冬小麦品种得到大量的春性品系。冬小麦的基因型和春化处理的时间对冬小麦的转化有明显影响。没有从无芒1号冬小麦品种得到春性品系。春性品系只出现在一定日数春化处理的后代中,但和春化处理日数之间没有规律性的联系。冬小麦向春小麦的转化是逐渐进行的,转化第三代是冬小麦向春小麦转化的关键时期。转化春小麦保持了原始冬小麦品种的一些质量性状,农艺性状表现出广泛的变异。改变冬小麦为春小麦可作为其他育种方法之外创造春小麦育种材料和丰富春小麦种质资源的一个新途径。     

Effect of Different Growth State of Broccoli （Brassica oleracea var. italica） on Low Temperature Induction

The productive organ of brocooli is curd which is consisted of main scape which was breviate and fleshy and some numbers of branch curds, whereas every branch curd consist of first grade lateral scape which was breviate and fleshy and other grades lateral scape and flower buds[1].The size and weight of broccoli was main determ ined by the num bers and bulk of branch curds which were associated with the developm ental extent differentiation by them selves closely. So floral bud differentiation …     

黄花芥蓝游离小孢子培养和植株再生

以黄花芥蓝自交品系ZBo-1和ZBo-6为供体材料,研究了培养基添加激素、热激时间、取材时期以及供体植株生长条件对小孢子胚状体产量的影响.结果表明,在32℃热激1 d小孢子胚产量最高,培养基中添加NAA 0.1 mg/L、IAA 0.1mg/L和6-BA 0.1mg/L能促进芥蓝小孢子胚状体的形成.不同时间取材,胚状体产量存在明显差异,胚状体诱导成功率在60%～80%.2个材料在人工春化温室栽培和自然春化温室栽培2种生长条件下都有子叶形胚和鱼雷形胚形成的 能力;ZBo-6在自然春化温室栽培条件下胚产量显著高于人工春化条件下的胚产量,而ZBo-1的胚产量以人工春化条件下较高.试验获得了黄花芥蓝的小孢子再生植株.     

小黑麦与普通小麦春化特性差异研究

采用盆栽低温春化试验方法,比较研究了小黑麦与普通小麦春化特性的差异。结果表明,小黑麦对春化反应的敏感性不及普通冬小麦,它的最适春化天数为30 d,而普通冬小麦为40 d,且幼穗分化进程比普通冬小麦早且快,低温春化时间的长短直接影响发育进程及速度;当超过最适春化天数时,随人工春化时间的加长,单株分蘖数、单株绿叶数、主茎叶龄、单株叶面积呈递减趋势,而单株鲜重与干重呈单峰曲线,其峰值即为最适春化期。