毕业论文移动版

摘    要水稻解决了世界几十亿人口的温饱问题，对于维持世界的稳定与和平起到了极大的促进作用。面对日益减少的耕地面积以及持续增长的世界人口，只有提高单位面积水稻的产量，才能解决其温饱问题。因此，如何提高单位面积水稻的产量成为了众多科学家研究的课题。对水稻产量的评价主要包含三个方面，一是单位面积水稻的穗数，二是平均每条穗上实粒的颗数，三是每一千粒水稻种子的质量，而分蘖直接影响水稻穗数的多少，从而影响水稻单位面积的产量。但是，目前人们对于水稻分蘖的形成机理还不清楚。89513

我们通过EMS 诱变籼稻品种蜀恢获得了一个分蘖减少突变体f17，利用该突变体与亲本蜀恢回交获得F1代，挑选含有突变体性状的水稻与野生型粳稻品种日本晴杂交，获得F2 代。从F2 代群体中随机选取分蘖减少突变体20 株，提取DNA，形成混池，然后用本实验室设计的在12条染色体上均匀分布的196条多态性引物进行扩增，筛选具有连锁趋势的分子标记，接着用单株进一步验证，基本确定突变基因所在位置。之后扩大定位群体，设计新的引物，完成突变基因的精细定位。最终，F17基因被限定在第一条染色体的M11-M16区间内。通过全基因组测序，我们发现该区间内只有一个ORF发生点突变。突变发生在第826位碱基由鸟嘌呤（G）突变为腺嘌呤（A），编码该氨基酸的密码子发生改变，使其翻译出的氨基酸由酪氨酸（Tyr）变成了天冬酰胺（Asn）。

该突变位点所在基因编码磷酸脱氢酶。因此，为了进一步测定突变前后酶的活性变化，我们将F17基因插入pET28a载体，进行F17蛋白诱导与纯化条件的初步摸索。结果发现，IPTG诱导所产生的蛋白分子量大小正确，且低温诱导更容易获得可融蛋白。另外，IPTG的浓度变化对该蛋白的诱导及纯化结果影响不大。当然，由于该实验只处于初步探索阶段，大多数条件都不是最适条件，因此未来我们将进一步摸索实验条件并获得高质量的F17蛋白。

毕业论文关键词：水稻； 分蘖； 图位克隆；蛋白

Abstract Rice, as the one of pivitol crops, support billions of people in the world。 With the shrinking arable land area and the continued growth of the population, it is necessary to improve the output of rice per unit area。 The factors in determining of the rice yield mainly includes three aspects:panicles per unit area, the filled grains per panicle and the weight of 1000 filled grains。 Tillers can affect the number of rice spike directly, and also affect the output of rice per unit area finally。 Therefore, what kind of molecular mechanism to determin rice tillering? It is the hot topic for plant scientists。 However, the molecular mechanism of rice tillering is still not clear so fat。源Q于W优E尔A论S文R网wwW.yOueRw.com 原文+QQ75201,8766

We made mutagenesis of the wild type rice SH527 with EMS and get a tillering reduce mutant f17。 To clone the F17 gene, the mutant backcross with SH, getting F1 generation。 And then the mutant phenotype lines  selected from F1 generation was backcrossed with wild type rice Nip to acquire the F2 generation。 We randomly select 20 mutant phenotype linesfrom the F2 population, and the DNA was extracted from those plant to form a mixture pool。 Then we amplify the mixed DNA with the 196 polymorphic primers which are uniformly distributed on 12 chromosomes。 After the completion of the primary mapping, several linked markers were picked up and more rice mutant plants from F2 population were applied to do further validation。 Finally, F17 gene is delimited into the interval of M11 - M16 on the first chromosome。 Within that region, a single mutation was found in the 826th base of one of ORFs, changed from guanine (G) in SHto adenine (A) in f17 mutant, which caused the encoding amino acid altered from tyrosine (Tyr) to asparagine (Asn)。 (责任编辑：qin)