水稻白化突变体Osalb24白化产生机制与生理性质分析

发布时间：2018-03-30 10:14

本文选题：水稻　切入点：致死白化突变　出处：《聊城大学》2017年硕士论文

【摘要】：植物白化是植物叶色突变的类型之一,主要是由于缺乏叶绿体色素所致。从植物发育的角度来看,叶绿体色素缺乏有两个原因,一是叶绿体发育正常,叶绿体色素合成受阻;二是叶绿体发育不正常,类囊体发育不完全,细胞内虽能够合成叶绿体色素,但合成的色素不能到达正确位置上发挥功能,随时降解。因此,白化植物叶片的全部或局部叶绿体色素含量为零或痕量。水稻是全球主要粮食作物,其叶色突变与产量直接相关。从叶色突变性状对个体生长发育影响角度来看,可分为致死突变、非致死突变和条件致死突变。其中致死突变是研究水稻叶绿体发育与光合作用的极好材料。水稻白化致死突变体在幼苗期依靠种子胚乳中储存的营养物质维持生长,待种子内的营养物质耗尽,植株死亡。本研究以水稻白化致死突变体Osalb24为试验材料,以野生型水稻为对照,观察该突变体生长发育的外部形态,在透射电子显微镜下观察该突变体三叶期的叶绿体发育情况,用分光光度计测定叶绿体色素含量,通过基因的连锁反应与图位克隆技术对Osalb24基因进行了粗略定位。结果表明:(1)从种子萌发到三叶期早期,白化幼苗和野生型一样,能够正常生长。但是无论是地上部分的茎叶,还是地下部分的根系,白化突变体Osalb24都比野生型长得细弱。三叶期中后期白化幼苗逐渐停止生长,最后死亡。(2)在透射电镜下观察,Osalb24突变体叶片的叶绿体结构与野生型的一样,都具有发育完全的类囊体,叶绿体发育正常。(3)Osalb24突变体叶片中叶绿素a和类胡萝卜素的含量为痕量,几乎测不出,叶绿素b的含量为0。(4)统计白化突变体的性状分离比,发现白化与正常水稻性状分离比值接近1:3,推测Osalb24属于隐形基因。(5)通过基因的连锁反应与图位克隆技术,确定白化基因Osalb24位于水稻第6号染色体4,422,676bp至5,196,144bp之间。根据以上研究结果可以推断,基因Osalb24位于水稻第6号染色体上,与水稻的叶绿体发育无关,但它影响叶绿体色素的合成。基因Osalb24导致的白化性状是隐性的,也就是说,该位点对应的显性基因表达是水稻叶绿体色素合成不可或缺的。
[Abstract]:Plant albinism is one of the types of leaf color mutation, mainly due to the lack of chloroplast pigment. From the point of view of plant development, chloroplast pigment deficiency has two reasons: first, chloroplast pigment synthesis is blocked due to normal chloroplast development; Second, the chloroplast development is abnormal, thylakoid development is not complete, although the cell can synthesize chloroplast pigment, but the synthesized pigment can not reach the correct position to play a function, degradation at any time. The total or partial chloroplast pigment content of albino plant leaves is zero or trace. Rice is the main food crop in the world, and its leaf color mutation is directly related to yield. Can be divided into lethal mutations, Non-lethal mutation and conditional lethal mutation, among which lethal mutation is an excellent material for studying chloroplast development and photosynthesis in rice. Rice albino lethal mutant maintains its growth at seedling stage by nutrients stored in the seed endosperm. In this study, rice albino lethal mutant Osalb24 was used as experimental material and wild type rice as control. The chloroplast development of the mutant at trefoil stage was observed under transmission electron microscope. The content of chloroplast pigment was measured by spectrophotometer. Osalb24 gene was roughly located by gene chain reaction and map cloning. The results showed that from seed germination to early trefoil stage, albino seedlings could grow normally just like wild type. The albino mutant Osalb24 was weaker than the wild type in the root system. The albino seedlings stopped growing gradually in the middle and late stage of trefoil stage, and finally died.) the chloroplast structure of leaves of Osalb24 mutant was observed under transmission electron microscope, which was the same as that of wild type. The contents of chlorophyll a and carotenoid in leaves of the chloroplast mutant. The content of chlorophyll a and carotenoid was almost undetectable, and the content of chlorophyll b was 0.44) the segregation ratio of the albino mutant was calculated. It was found that the ratio of albinism to normal rice character segregation was close to 1: 3, which suggested that Osalb24 was an invisible gene. It was determined that the albino gene Osalb24 was located between chromosome 6 4422676bp and 5196144bp in rice. Based on the above results, it can be inferred that the gene Osalb24 is located on rice chromosome 6 and has no relation to chloroplast development in rice. But it affects the synthesis of chloroplast pigments. The albinism characters caused by gene Osalb24 are recessive, that is to say, the dominant gene expression corresponding to this locus is indispensable for chloroplast pigment synthesis in rice.
【学位授予单位】：聊城大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S511

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