目录
摘要Ⅱ
关键词Ⅱ
AbstractⅢ
引言
引言（或绪论）1
1材料与方法3
1.1 实验材料 3
1.1.1植物材料 3
1.1.2实验仪器 3
1.2实验方法 3
1.2.1提取野生型和突变体不同穗发育时期的穗部RNA3
1.2.2采用同源克隆法克隆突变体中的Q基因5
1.2.3 QRTPCR技术（实时荧光定量PCR）8
1.2.4本实验使用的引物信息 9
2结果与分析9
2.1野生型和突变体的生育期农艺性状差异9
2.2 5AQ的变异克隆 10
2.3 5AQ的变异对植株表型的影响11
3讨论12
3.1 Q基因的调控功能12
3.2 5AQ在小麦育种中的价值12
3.3 miR172对小麦的调控影响 12
致谢14
参考文献15
小麦驯化基因Q的再次演绎
摘 要
Q是普通小麦在异源六倍体化过程中自发突变产生的一个重要驯化基因，其突变发生于miR172的调控位点，导致miRNA对其靶向作用降低，Q表达水平提高。本研究在小麦品种02Y393的EMS诱变后代中发现了两个植株矮化、穗密度增加的突变体，暂时记为SL480和SL622，推测为Q在miR172调控区域的再次突变所致。对这个两个突变体的Q（即5AQ）及其位于5D染色体的部分同源基因5Dq基因进行同源克隆，发现突变体的5Dq序列没有发生碱基的突变，而5AQ基因均鉴定为单碱基的突变，尽管突变位点不同，但均发生在miR172调控区域，比较突变体和野生型中5AQ基因的表达量，发现两个突变体中的5AQ基因表达量均显著高于野生型的，表明miR172对它们的靶向作用都降低，导致突变体中的5AQ表达提供，引起突变体性状的变化。进一步分析发现SL480中的5AQ表达水平高于SL622中的，这也导致了SL480较SL622更矮，穗密度更大。其中SL480突变发生于3147bp处，SL622突变发生于3157bp，表明不同位点的突变可能导 *51今日免费论文网|www.jxszl.com +Q: ^351916072* 
致miR172对它们的靶向效率有差异，从而影响Q表达和表型的差异。本研究中的突变体为Q的再次演绎，其表达水平高低影响小麦株型的建成，对其表达水平进行调控可以获得“理想”的株型。
History repeats itself for wheat domestication gene Q
ABSTRACT
Q gene is an important domestication gene derived from spontaneous mutation of wheat during heterohexaploization. The mutation occurs at the regulatory site of miR172, resulting in the decrease of miRNA targeting effect and the increase of Q expression level. In this study, two mutants were identified from EMS induced progenies of wheat variety 02Y393, temporarily named as SL480 and SL622. The mutants showed dwarfing height and increased spikelet density. It is speculated that the mutation occurred once again in Q of miR172 regulatory region. The Q (5AQ) of the two mutants and the 5Dq gene of their homologous genes located on the 5D chromosome were homologously cloned. It was found that the 5Dq sequence of the mutants had no difference, while a single nucleotide mutation each was identified in the 5AQ gene. Although the mutation sites were different, they all occurred in the miR172 regulatory region. Comparing the expression of 5AQ gene in the mutants and wildtype mutants, expression of 5AQ gene in two mutants were significantly higher than that in the wild type, indicating that miR172 had lower targeting effect on them. This led to the abundant 5AQ expression in the mutant and the changed plant architecture. Further analysis showed that the expression level of 5AQ in SL480 was higher than that in SL622. Consistently, SL480 showed more dwarfing height and higher spike density than SL622. Mutation occurred at 3147bp in SL480 and it occurred at 3157bp in SL622. We speculated the mutations at different sites may cause the differences of the targeting efficiency for miR172, thus affecting the difference of Q expression and phenotype. The mutants obtained in this study reflected the history that repeats itself of Q. Its expression level affects the establishment of wheat plant architecture. The proper regulation of Q expression level could lead to the "ideal" plant in breeding.

原文链接：http://www.jxszl.com/nongxue/zwbh/606162.html