【作者】 周鹏；

【导师】 李平；

【作者基本信息】 四川农业大学 ， 作物遗传育种， 2009， 硕士

【摘要】 水稻是世界上最重要的粮食作物之一,其花器官的发育结果直接影响稻谷产量和稻米品质。作为单子叶和禾本科植物的模式植物,水稻花器官发育调控的遗传和分子机制研究已成为植物发育生物学研究的热点。发育生物学的发展促进了对植物花器官形态、属性的认识,与花器官发育相关基因的研究已成为植物发育生物学研究的热点。花的发育是开花植物生殖生长期最明显的特征,花器官的形成程序则是植物的重要遗传特征之一,植物花的发育是营养生长向生殖生长转变的结果。这种转变导致形成一个比营养器官更为复杂的结构,即花序。因此,植物花的形态发育过程为研究基因调控的分子机理提供了一个合适的系统。水稻作为单子叶植物的模式植物,研究水稻生殖发育,特别是关于开花起始诱导和花器官发生等的分子遗传机理,在理论和实践上都具有重要意义。在双子叶模式植物拟南芥和金鱼草中已发现了多个花序变异突变体,并已克隆了相关基因,如拟南芥中的LFY和TFL及金鱼草中的FLO等。在单子叶植物水稻中,也已经获得了一些花序形态结构发生变异的突变体,如穗轴卷曲突变体fzp和稀穗突变体lax。前期研究中,我们在籼稻保持系抗丰B与金谷B的杂交后代中发现了一个簇生穗突变体（Cl-dz）。本研究通过穗部解剖结构、石蜡切片、扫描电镜观察和突变性状的遗传分析等方面对该突变体进行了鉴定,并对其相关基因进行了初步的分子标记定位。主要结果如下:1 Cl-dz突变体的表型特征与野生型水稻相比,突变体的植株稍高,株型较为松散,小穗数目略有下降,谷粒稍大。在二次枝梗顶端2-3粒小穗簇生在一起,呈“W”形,育性、结实正常。解剖镜观察发现,突变体在二次枝梗顶端小穗着生部呈现不同,突变体比野生型小枝梗排列更紧凑。石蜡切片观察,在二次枝梗顶端小穗小枝梗着生部细胞没有发现异常。2扫描电镜观察突变体枝梗发育过程从苞原基至雌雄蕊原基发育,突变体与野生型没有明显差别。从雌雄蕊原基发育到小花内外稃闭合时期,突变体出现了异常。由于二次枝梗及其顶端小穗的小枝梗发育受阻,导致二次枝梗上的2-3粒小穗簇生在一起。3突变性状的遗传分析以突变体作为父本,与多个水稻材料杂交衍生F2群体,或利用杂交F1与突变体回交衍生BC₁F₁代植株,调查突变性状在各种背景下的分离。突变性状的分离分析表明,F₂分离群体正常株与突变株均符合3:1的分离比例,BC₁F₁群体符合1:1的比例,表明该突变性状受一对隐性基因控制,暂时将该基因命名为Cl-dz。4突变基因的定位以G46B与Cl-dz配制的F₂群体为定位群体,选取6号染色体上的已公布的SSR标记进行遗传连锁分析,将基因定位在SSR标记RM1340和RM6036之间,遗传距离分别为3.6CM和7.0CM。更多还原

【Abstract】 Rice is one of the most important grain crops in the world.The developmental result of the floral organ directly influences on the output and the quality of rice.Rice is a representative monocotyledon and a gramineous model crop.The research on the genetic and molecular mechanism of the developmental regulation of rice floral organ has been the focal point of research on the developmental biology of plants.The development of the developmental biology of plants has improved the knowledge about the shape and the attribute of the floral organ,which has been the focal point of research on the developmental biology of plants together with the research on floral organ development related gene.The development of flower is the obvious characteristic in the reproductive growth period.The forming process of the floral organ is one of the importance characteristics of plants.The development of flower is the result of transformation from vegetative growth to reproductive growth.Such a transformation causes the formation of a structure more complex than the vegetative organ,that is,inflorescence.Therefore,the process of the morphological development of flower provides a system suitable for the research on the molecular mechanism of the genetic regulation.The rice is the model plant of the monocotyledon so the researches on the reproductive development of rice, especially the molecular genetic mechanisms of flower induction and floral organ generation,are important in theory and in practice.Multiple inflorescence mutants have been found in dicotyledonous Arabidopsis thaliana and Antirrhinum majus;and the related genes thereof,such as LFY and TFL in Arabidopsis thaliana and FLO in Antirrhinum majus,have been cloned.Some inflorescence mutants relating to the mutation of morphological structure,such as spike-stalk curled mutant FZP and lax-spiked mutant Lax,have been also found in monogenus rice.A fascicled mutant（Cl-dz） has been found in the filial generation of maintainer line Kangfeng B and Jin-gu B of indica rice.Such a mutant was identified through observation of spike anatomy and paraffin section,observation under scanning electronic microscope and genetic analysis of the mutant character.The related genes thereof were primarily located by molecular marker.The main results are as follows: 1.Phenotypic characteristic of Cl-dz mutant:Compared with wild type,the mutant tyre is slightly higher;the plant type is not compact;the number of the spikes decreases a little; and the grain is a little bigger.Two or three pieces of spikes at the top of the secondary rachis branch are fascicled in ’W’ shape.Flowering and fructification are normal.Being observed under the anatomical lens,the mutant has more cells than the wild type at the growing parts of the last two spikes at the top of the secondary rachis branch.Being observed from the paraffin section,no anomaly was found at the growing part of the spike at the top of the secondary rachis branch.2.Observation of developmental process of mutant spike under scanning electronic microscope:The mutant had no obvious difference from the wild type during the forming process from bract primordium to floral primordium;the mutant was abnormal during the period from floral primordium to closure of flower glume;two to three pieces of spikes at the top of the secondary rachis branch were fascicled due to the abnormal development of the rachis branch of the top spike.3.Genetic analysis of mutant trait:The F₂ and BC₁F₁ populations came from the mutant crossing with other rice materials and investigated mutant characteristics under each kind of background separation,the separate analysis of the mutant character showed that the F₂ separation proportion of the normal plants to the mutant plants was 3:1 and the BC₁F₁ was 1:1.It showed that the mutant character was controlled by a pair of recessive genes,which was temporarily called Cl-dz.4.The F₂ population came from the mutant crossing with G46B was used to map the gene.The publicized SSR marker on the chromosome No.6 was selected for genetic linkage analysis;the gene was located between SSR marker,that is,RM1340 and RM6036;and the genetic distances were 3.6 CM and 7.0 CM,respectively.更多还原