【作者】 李昱；

【导师】 赵淑清；

【作者基本信息】 山西大学 ， 生物化学与分子生物学， 2008， 硕士

【摘要】 开花转变是植物个体发育中最关键的过程。在模式植物拟南芥（Arabidopsisthaliana）中,存在4条互相依赖、共同作用的调控开花时间的信号途径,包括光周期途径、春化途径、自主途径和赤霉素途径。通过分离、鉴定各种早花、晚花突变体,已经克隆了许多开花时间基因,但相对于植物开花调控的复杂性,我们所掌握的信息仍然很有限。我们以模式植物拟南芥为材料,在Columbia生态型中筛选得到一个晚花突变体,命名为flowering locus x（FLX）。本研究构建了基因定位的作图群体,对开花控制基因flx进行了定位,并且研究了春作用对该晚花突变体的影响。首先将突变体flx植株与不同遗传背景的野生型Ler杂交产生子一代（F₁）,F₁代自交产生F₂代。从播种的2350株F₂代植株中选出了370株具有晚花表型的植株作为基因定位的作图群体。然后利用以PCR为基础的简单序列长度多态性标记（SSLP）对作图群体中的所有个体进行检测,通过分析目的基因flx与各分子标记之间的连锁关系,将开花控制基因flx定位于拟南芥第5条染色体分子标记T24H18-25983附近。同时,本论文工作对突变体flx和野生型Col分别进行3周、4周、5周和6周的春化处理,同期种植正常春化处理2天的突变体flx和野生型Col作为对照,分析了春化作用对拟南芥晚花突变体flx开花时间的影响。实验结果显示,突变体经flx春化处理5周后,晚花表型基本被逆转,表型和野生型Col基本一致,当春化处理6周后,基本不能再进一步加速开花进程,春化处理达到饱和状态。因此,我们认为FLX基因突变并不影响对春化作用的应答,也就是说,突变基因flx对于开花的抑制并不是通过春化作用途径实现的。更多还原

【Abstract】 The transition to flowering is the most critical process during the plant life cycle. The genetic and molecular analyses of Arabidopsis thaliana have revealed four interdependent genetic pathways for flowering: photoperiod, vernalization, autonomous, and gibberellin pathway. Although many flowering time gene have been cloned by isolating and identifying early- and later-flowering mutants, our understanding of flowering time control is still limited. A late-flowering Arabidopsis mutant （refer to as flx） was isolated from EMS-mutagenized plants of the Col ecotype in our lab. In this study, F₂ population was generated, mutant F₂ individuals were genotyped for SSLP molecular markers polymorphism, and the vernalization effect on flowering time on flx was studied.For mapping the flx locus, homozygous flx plants （ecotype Columbia） were outcrossed to wild type plants （ecotype Landsberg）, and the resulting F₁ plants were allowed to self-fertilize to generate F₂ population. 370 late-flowering plants in the F₂ population were selected, and mutant F₂ individuals were genotyped for SSLP molecular markers polymorphic between Col and Ler. Analysis of the relationships of the gene flx with the molecular markers showed that the flx locus is located near of the markers T24H18-25983 on chromosome 5.In addition, the effect of the vernalization on flowering time of mutant flx and wild type plants was studied. The experiment showed that the late-flowering phenotype of the mutant could be restored by 5 weeks treatment of vernalization, but the 6 weeks treatment could not further accelerate the transition. This result implies that the FLX gene is not a component of the vernalization pathways.更多还原