玉米穗粒数相关性状QTL定位与候选基因关联分析

发布时间：2018-01-01 09:35

本文关键词：玉米穗粒数相关性状QTL定位与候选基因关联分析　出处：《华中农业大学》2016年博士论文　论文类型：学位论文

【摘要】：玉米作为重要的粮食作物,同时兼作饲料以及工业原料,集三大属性于一身。随着人民生活质量的提高,农牧产品需求量日益增加;化石能源供应的持续紧张,清洁能源如生物乙醇的需求日益迫切,进一步加剧了全球范围内玉米供需的紧张局势(Keyzer et al 2005;Wirsenius et al 2010)。穗粒数是玉米产量构成因子,也是重要的育种目标。穗长、行粒数和穗行数与每穗籽粒数密切相关,这些重要的因子最终决定玉米籽粒产量。因此,通过改良玉米穗粒数等相关性状,可以有效的提高玉米产量。对玉米穗粒数相关基因进行探究和分析,对分子标记辅助选择改良玉米而言,具有极其深远的意义。本研究利用玉米自交系TY6分别与Mo17和W138组配F2分离群体以及F2:3家系进行全基因组穗粒数相关性状QTL定位,对主效QTL qEL1.10进行重定位,并评估其育种潜力。另外,基于前人定位到的一个穗粒数相关位点qEL7.02,对其展开精细定位工作,并对重要候选基因进行关联分析,发掘重要的功能位点。主要结果如下:1.利用TY6×W138(WT)和TY6×Mo17(MT)衍生的两套F2:3家系,对穗长、行粒数、穗行数以及穗重4个性状进行QTL定位,共检测出39个QTLs,单个QTL可以解释的表型变异范围为0.4%-29.5%。此外,14个分布在第一、四、五、七和十号染色体上的14个QTLs共形成5个QTL簇,其中位于第一号染色体长臂的QTL簇内共包含6个穗粒数相关性状的QTLs,将其命名为qEL1.10。2.由TY6×W138与W138回交,结合对qEL1.10的分子标记辅助选择,发展了一个QTL-NIL分离群体。使用QTL区段内新开发的8对分子标记,对qEL1.10进行重定位,发现qEL1.10为一个一因多效的QTL,同时控制穗长、行粒数以及穗重等性状,所解释的表型变异分别为42%,49%和25%,来源于TY6的等位基因的加性效应值分别为-1.58 cm,-3.67粒和-8.9 g。3.利用NIL系:W138和W138TY6(qEL1.10位置为TY6等位基因)分别与六个玉米骨干自交系杂交,其F1在穗长、行粒数以及穗重性状上,均显示来自W138的优良等位基因能将穗长提高0.77厘米,行粒数增加1.42粒以及穗重增重4.31克。由此表明,该QTL位点在提高果穗籽粒数目以及粮食产量方面具有一定的育种潜力。4.在前人将qEL7.02定位到6.3Mb区段内的基础上,利用回交群体筛选交换单株,通过子代测验的跨叠系表型鉴定,将目标QTL缩小到605Kb的区间(基于B73参考基因组)。5.结合生物信息学分析。在目标区段内的候选基因中,发现Candidate gene 1与玉米中id1的功能domain有同源性,而id1突变体的纯合表型表现为花期延迟以及花序发育异常。对该候选基因进行序列分析发现,在近等基因系SL17-1和Ye478之间,Candidate gene 1在ATG上游以及第一外显子区共发现55个多态性差异位点,包括21个Indels和34个SNP位点。其中编码区内的差异仅有两处,且都位于第一外显子,分别为第68和第111位。第111位的G/C变异并不造成编码氨基酸的改变,而第68位除了T/C变异外,在亲本SL17-1中又有六个碱基的插入,最终引起该位置由Ye478中的脯氨酸变成SL17-1中的亮氨酸、苏氨酸和精氨酸。6.候选基因关联分析表明,Candidate gene 1第一外显子上三处多态性位点影响与抽雄期、吐丝期和散粉期显著关联(In-68:P=0.0073;P=0.0009;P=0.0068),但并未检测到影响玉米穗长的变异位点。
[Abstract]:Maize is an important food crop, also be used as feed and industrial raw materials, set three properties in one. With the improvement of people's living quality, the demand for agricultural products is increasing; fossil energy supply shortage, clean energy such as bio ethanol demand increasingly urgent, further exacerbated tensions in the global scope of corn supply and demand (Keyzer et al Wirsenius et 2005; Al 2010). The grain number per spike is the factor of yield structure, is also an important breeding target. Panicle length, grain number per row and row number and kernel number per ear is closely related to these important factors ultimately determine the grain yield of maize. Therefore, the improvement of maize grain the number of characters, can effectively improve the maize yield of maize. Spike related gene probes and analysis of molecular marker assisted selection of improved maize, has far-reaching significance. This study used Maize inbred lines TY6 and Mo17 respectively and W138 group with F2 group and the F2:3 lines were isolated whole genome panicle traits of QTL positioning, re positioning of the main effect QTL qEL1.10, and to evaluate its breeding potential. In addition, the previous location to a spike related sites of qEL7.02 based on fine positioning on it, and the important candidate genes for association analysis, explore the important functional sites. The main results are as follows: 1. using the TY6 * W138 * Mo17 (WT) and TY6 (MT) derived from two sets of F2:3 family, the panicle length, grain number per row, QTL positioning ear row number and panicle weight of 4 characters like, detected a total of 39 QTLs, a single QTL can explain the variation of phenotype for 0.4%-29.5%. in addition, 14 in first, fourth, five, 14 and seven QTLs on chromosome ten were divided into 5 QTL clusters, the cluster QTL is located in chromosome number 1 in a total of 6 spike grain number The characters of QTLs, named qEL1.10.2. by TY6 * W138 and W138 backcross with marker assisted selection of qEL1.10, the development of a QTL-NIL segregation population. 8 of the molecular marker QTL section in the newly developed, re positioning of the qEL1.10, found that qEL1.10 is a pleiotropic QTL. At the same time control for panicle length, grain number and grain weight traits, the phenotypic variation explained by respectively 42%, 49% and 25%, additive effect from TY6 allele values were -1.58, cm, NIL and -8.9 g.3. using -3.67 particle: W138 and W138TY6 (qEL1.10 position TY6 allele respectively) and six inbred lines of maize hybrid, the F1 in panicle length, grain number and panicle weight traits, showed excellent alleles from W138 to panicle length increased 0.77 cm, grain number and panicle weight increased 1.42 grain weight 4.31 grams. It showed that the QTL locus in improve seed ear The grain number and grain yield of.4. breeding potential in previous qEL7.02 to locate the 6.3Mb section on the basis of screening exchange plant by backcross populations, by overlapping progeny test phenotypic identification, the target QTL reduced to 605Kb interval (based on the B73 reference genome.5.) combined with bioinformatics analysis the candidate gene in the target region. In 1, Candidate gene and function of domain corn Id1 homology, and the homozygous Id1 mutant phenotypes for flowering delay and inflorescence development. The abnormal genes sequence analysis found that between near isogenic lines SL17-1 and Ye478, Candidate gene 1 in the ATG upstream of the first exon 55 polymorphism sites were found, including 21 Indels and 34 SNP loci. The difference of encoding area is only two, and are located in the first exon, respectively. For sixty-eighth and 111st. 111st G/C mutation does not cause the changes of encoding amino acid, and sixty-eighth in addition to the T/C variation, in the parent SL17-1 and insertion of six nucleotides, resulting in the position of a proline in the Ye478 to become SL17-1 leucine, lysine threonine.6. candidate gene association and precision analysis showed that Candidate, gene 1 exon three polymorphism loci on and tasseling, silking and anthesis were significantly correlated (In-68:P=0.0073; P=0.0009; P=0.0068), but did not detect the effect of corn ear length variation sites.

【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】：S513

【相似文献】