相引相株高基因qPh3和产量QTL qYd3的遗传解析和SD1基因内重组的鉴定

发布时间：2018-05-26 02:39

本文选题：水稻 + 株高　；参考：《华中农业大学》2016年博士论文

【摘要】：高产是水稻遗传育种的重要目标。水稻产量由分蘖数、千粒重和每穗实粒数构成,此外,株型对水稻产量也有重要的影响。QTL定位以及图位克隆是发掘新基因的重要手段。利用前期02428和Teqing(TQ)的重组自交系(Recombinant Inbred Lines,RILs)群体定位到的主效株高QTL q Ph3,构建了以TQ为供体02428背景的近等基因系,在此基础上进行q Ph3的图位克隆以及功能研究。同时,在珍汕97(Zhenshan 97,ZS97)和明恢63(Minghui 63,MH63)的RILs群体中发现一个株高达到160 cm的家系RI92,通过与ZS97回交的方法构建近等基因系,并对控制株高的基因进行图位克隆。主要结果如下:1.对qPh3进行遗传分析发现,02428等位基因型具有6.2 cm的加性效应和3.5 cm的显性效应,并有增加产量的效应。q Ph3初步定位在WPh1到RM7389之间,通过筛选大群体中的重组单株,进行后代测验确定q Ph3的基因型,把q Ph3精细定位在19-kb的区域内,两端标记分别为WPh10-1和RM7389,其中包含Os GA20Ox1在内的两个基因,亲本间比较测序发现Os GA20Ox1的编码区有一个SNP改变蛋白质的编码序列,由02428等位基因型的丙氨酸(Ala)改变为TQ等位基因型的缬氨酸(Val)。对Os GA20Ox1在近等基因系间的表达量分析发现,02428基因型具有比TQ基因型更高的表达。2.超表达Os GA20Ox1的中花11株高增加,证明Os GA20Ox1就是qPh3中控制株高的基因。因为,Os GA20Ox1编码GA20氧化酶,催化GA12和GA53到GA9和GA20过程中一系列的反应,所以测定了近等基因系和转基因植株中内源GAs的含量,结果表明,Os GA20Ox1的底物GA12和GA53在TQ近等基因系和转基因阴性植株中得到积累,而产物GA20在02428近等基因系和转基因阳性植株中明显提高,最终导致了02428近等基因系和转基因阳性植株中活性GAs不同程度地提高,印证了Os GA20Ox1是通过GAs含量影响水稻株高。3.超表达Os GA20Ox1并不增加产量的现象与近等基因系中02428等位基因型增加产量不一致,所以此基因组区段很可能还有一个控制产量的基因q Yd3,并通过挑选Os GA20Ox1纯合为02428等位基因型,其他区段为分离的家系与02428回交获得BC5F2群体用于产量QTL的定位和克隆。对BC5F2中q Yd3的定位分析发现,其具有较高的增产潜力,q Yd3对每穗实粒数具有24粒的加性效应和14.9粒的显性效应,对粒宽具有0.08 mm的加性效应和0.03 mm的显性效应,对千粒重具有0.7 g的加性效应和1.0 g的显性效应,对产量具有4.1 g的加性效应和4.3 g的显性效应。而且定位到这些的增效等位基因均是来源于02428。所以连锁的q Yd3和q Ph3是一对相引相基因,在育种过程中只要针对一种性状进行选择就可以实现产量和株高的改良。4.对RI92家系中控制株高的基因定位分析发现,SD1很有可能是候选基因,两亲本以及RI92中SD1测序确定了RI92中在+1721到+2575之间发生了一次基因内的重组,导致由ZS97的提前终止密码子TAG改变为MH63的TAC,从而使SD1可以翻译成完整的GA20氧化酶蛋白,苗期多效唑的处理进一步证明了SD1/SD1近等基因系具有更强的GAs合成能力。近等基因系产量性状的考察显示SD1/SD1具有增加单株产量的作用,但是降低收获指数和单位面积植株数目,同时具有容易倒伏的风险。5.qPh3和SD1均在染色体端粒附近,在定位过程中,二基因所在染色体区段的重组率比基因组平均增高4倍左右,显示重组热点特征。这与染色体端粒附近一般具有重组热点的观点一致。
[Abstract]:High yield is an important target of rice genetic breeding. The yield of rice is composed of tiller number, thousand grain weight and the number of grain per panicle. In addition, the plant type has an important influence on the rice yield..QTL location and map cloning are the important means to excavate new genes. The recombinant inbred line (Recombinant Inbred Lines, RILs) population of early 02428 and Teqing (TQ) is used. QTL Q Ph3 of the main effect plant was located, and the near isogenic line with TQ as the donor 02428 background was constructed. On this basis, the mapping and functional study of Q Ph3 were carried out. At the same time, a family of 160 cm was found in the RILs population of Jen Shan 97 (Zhenshan 97, ZS97) and Minghui 63 (Minghui 63, MH63). The near isogenic lines were constructed and the genes of the control plant height were cloned. The main results were as follows: 1. the genetic analysis of qPh3 showed that the 02428 allele type had 6.2 cm additive effect and 3.5 cm dominant effect, and the effect of increasing yield was initially located between WPh1 and RM7389, by screening the recombinant of large population. The genotypes of Q Ph3 were determined by progeny test, and Q Ph3 was finely located in the region of 19-kb. The two ends were labeled WPh10-1 and RM7389 respectively, including two genes including Os GA20Ox1, and the encoding region of Os GA20Ox1 was found to have a coding sequence of the SNP change protein, and the 02428 allele type alanine. A) changed into the TQ allele type valine (Val). The analysis of the expression of Os GA20Ox1 in the near isogenic lines showed that the 02428 genotype was higher than that of the TQ genotype, which expressed the high expression of.2. overexpression Os GA20Ox1, which proved that Os GA20Ox1 was the gene of the control plant in qPh3. A series of reactions in the process of GA53 to GA9 and GA20, so the content of endogenous GAs in the near isogenic lines and transgenic plants was measured. The results showed that the substrate GA12 and GA53 of Os GA20Ox1 were accumulated in the TQ near isogenic lines and transgenic negative plants, while the product GA20 was obviously improved in the 02428 near isogenic lines and the transgenic positive plants. In the end, the active GAs in 02428 near isogenic lines and transgenic positive plants increased in varying degrees. It was confirmed that Os GA20Ox1 was not consistent with the increase of the yield of the high.3. overexpression Os GA20Ox1 in rice plant by GAs content, which was not consistent with the increase of the yield of the 02428 allelic genotypes in the near isogenic lines, so the genome section of this genome is likely to be still available. A gene Q Yd3, which controls yield, was selected by selecting Os GA20Ox1 homozygous as 02428 alleles. The other segments were separated from family and 02428 backcross to obtain BC5F2 population for location and cloning of yield QTL. The localization analysis of Q Yd3 in BC5F2 showed that it had higher yield potential and Q Yd3 had 24 additive effects on the number of grains per panicle. The additive effect and the dominant effect of 0.08 mm to the grain width and the dominant effect of 0.03 mm on the grain width, the additive effect and the dominant effect of 1 g on the 1000 grain weight, with the additive effect of 4.1 g and the dominant effect of 4.3 G on the yield, and the alleles of these synergies are derived from the Q Yd3 and the chain of Q Yd3 and the linkage of these genes. Q Ph3 is a pair of phase induced gene. In the breeding process, the gene localization analysis of improved.4. for yield and plant height in RI92 family can be achieved by selecting a kind of character. It is possible that SD1 is a candidate gene. Two parents and SD1 sequencing in RI92 have confirmed that RI92 has occurred between +1721 and +2575 in RI92. The recombination in the gene resulted in the change of the early terminated codon TAG of ZS97 to the TAC of MH63, so that SD1 could be translated into a complete GA20 oxidase protein. The treatment of the seedling stage of Paclobutrazol further demonstrated that the near isogenic lines of the SD1/SD1 had a stronger GAs synthesis ability. The investigation of the yield traits of the near isogenic lines showed that SD1/SD1 had an increase in single plant. The effect of yield, but reducing the harvest index and the number of plants per unit area, at the same time having the risk of easy lodging,.5.qPh3 and SD1 are all near the telomere of chromosomes. During the localization process, the recombination rate of the chromosome section of the two gene is 4 times higher than the average of the genome, which shows the feature of the recombination hot spot. This is common with the telomere of chromosomes. There is a consistent view of reorganizing hot spots.
【学位授予单位】：华中农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S511

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