烟草钾含量遗传变异的全基因组关联分析

发布时间：2018-01-06 00:18

本文关键词：烟草钾含量遗传变异的全基因组关联分析　出处：《中国农业科学院》2016年硕士论文　论文类型：学位论文

【摘要】：烟草(Nicotiana.tabacum)是我国重要的叶用性经济作物,烟叶钾含量的高低严重影响着烟叶经济价值的大小。与国外优质烟叶相比,我国烟叶钾含量普遍偏低,严重制约了我国烟草产值的提高,也减缓了偏远山区农民脱贫致富的步伐。针对我国烟叶钾含量偏低问题,传统的栽培施肥措施效果并不理想。因此,通过发掘烟草中与钾吸收转运相关基因,开发功能标记,进行分子标记辅助选择育种的办法,达到提高烟叶钾含量的目的。本研究在烟草核心种质的基础上筛选了96份烤烟材料构建了试验群体,简称群体Ⅰ。同时构建了130份烟草材料的验证群体,简称群体Ⅱ。利用均匀分布于全基因组上的454个SSR标记对群体Ⅰ进行遗传多样性分析和群体结构分析,并基于标记-性状关联分析的结果,筛选与钾吸收转运相关的SSR标记和候选基因,构建了一套高钾烟草种质的分子标记辅助筛选体系。主要结果如下:(1)对不同环境下烟叶钾含量的分析发现,在相同年份中,西昌烟叶钾含量显著高于诸城。与此相反,西昌烟叶钾含量的变异系数却明显小于诸城烟叶钾含量的变异系数。这从侧面上说明,西昌比诸城更具有生产优质烤烟的潜力。此外,在西昌和诸城两地,国内种质与国外种质在烟叶钾含量上的表现无明显差异。(2)利用均匀分布于24条连锁群的454个SSR标记对96份烤烟进行全基因组扫描。对检测到的等位变异频率按5%的比例进行稀有等位过滤。过滤后具有多态性的标记为417个。检测到的等位变异共1038个,平均为2.5个,变幅为2-6个。平均PIC值为0.299,变幅为0.044-0.698。(3)基于Nei氏遗传距离进行的NJ聚类分析表明,96份的烤烟群体可以分为三类。此外利用Structure软件进行的群体结构分析同样表明,该96份烤烟群体存在3个亚群。这进一步说明该烤烟群体存在着三种遗传背景。(4)采用关联分析的方法,共发掘到-log P值≥2.00的标记16个,-log P值最高的标记为PT61367,达到4.46。其中PT51364、PT53362、PT55319这三个标记的重复性较好,同时关联到了两个环境的表型。此外,利用16个标记在烟草基因组数据库中的定位结果,在标记周围共筛选到4个与烟草钾吸收转运相关的候选基因,分别为Ntab0898590、Ntab0163850、Ntab0171930、Ntab0562640。其中前两个候选基因功能类似于钾通道基因,后两个候选基因功能类似于钾转运体基因。(5)对关联分析得到的-log P值≥2.50的11个关联标记进行高钾含量优异等位分析。通过对各标记各等位位点间表型差异的显著性检验和年点分布规律的统计,最终筛选出了5个SSR标记用于构建烟草高钾品种分子标记辅助筛选体系。5个SSR标记为PT61367、PT51364、PT30132、PT55319、PT53362,其优异等位分别为101、102、103、101103、101。此外在供试群体Ⅰ中发现,供试材料含有这些标记中优异等位的数量越多,其钾含量越高。用群体Ⅱ进行验证,得到了相同结果。说明这5个标记可应用于高钾烟草种质的分子标记辅助选择。
[Abstract]:Tobacco (Nicotiana.tabacum) is an important economic crop leaf, the potassium content in tobacco leaves seriously affects the economic value. Compared with foreign high-quality tobacco, China's tobacco leaf potassium content is generally low, which seriously restricts the improvement of tobacco output, also slowed the pace of poverty alleviation in the remote mountainous areas aiming at the problem of our country. The low potassium content in tobacco leaves, the effect of the traditional measures of cultivation and fertilization is not ideal. Therefore, absorption and transport related genes and potassium in tobacco by exploring the development, functional marker, molecular marker assisted selection breeding method to improve the potassium content of tobacco leaf. This research is based on the selection of core tobacco germplasm 96 copies of the test material in the construction of tobacco group, referred to as group 1. Also established 130 tobacco materials verification group, referred to as group II. Using a uniform distribution throughout the genome of the 454 A SSR marker of group I analyzed genetic diversity and population structure analysis, and based on the marker trait association analysis, screening and potassium uptake transporter related SSR markers and candidate genes, construct a set of high potassium of Tobacco Germplasm by molecular marker assisted selection system. The main results are as follows: (1) analysis of tobacco the content of potassium in different environment, in the same year, Xichang tobacco potassium content was significantly higher than that in Zhucheng. On the contrary, the coefficient of variation of Xichang tobacco potassium content was significantly less than Zhucheng tobacco leaf potassium content. From the side of that, Xichang has more than Zhucheng flue-cured tobacco production potential. In addition, in both Xichang and Zhucheng, no significant difference between the performance of domestic and foreign germplasm Germplasm in the potassium content in tobacco leaves on. (2) using 454 SSR markers evenly distributed in 24 linkage groups of 96 samples of Flue-cured Tobacco by whole genome scanning. The detected allele frequency of rare alleles were filtered according to the proportion of 5%. After filtration markers with polymorphism is 417. The detected alleles were 1038, the average is 2.5, the range was 2-6. The average PIC value was 0.299, ranged from 0.044-0.698. (3) analysis showed that NJ Nei's genetic distance clustering based on 96 groups of flue-cured tobacco can be divided into three categories. The population structure analysis using Structure software also shows that the 96 flue-cured tobacco group has 3 subgroups. This further indicates that the flue-cured tobacco group there are three kinds of genetic background. (4) mining method by correlation analysis the total excavation to the -log P value is more than 2 of the 16 markers, -log P is the highest marker for PT61367, 4.46. PT51364 PT53362, which reached PT55319, repeatability of these three markers is good, also related to the phenotype of the two environments. In addition, the use of 16 gene markers in tobacco The positioning results group in the database, the markings around were screened and 4 candidate genes related to tobacco potassium uptake, respectively Ntab0898590, Ntab0163850, Ntab0171930, Ntab0562640.. Two of the candidate genes similar to potassium channel gene, two candidate gene function similar to potassium transporter gene (5) on. Correlation analysis of obtained -log P for high potassium content of excellent analysis value of the 11 markers associated with = 2.50. Statistical significant test for differences in phenotype by each marker alleles between the years and point distribution, finally we selected 5 SSR markers were used to construct tobacco high potassium varieties of molecular marker assisted selection.5 SSR marked PT61367, PT51364, PT30132, PT55319, PT53362, the superior allele was 101102103101103101 in the test group I found in the tested materials containing these markers in the superior allele The higher the number, the higher the potassium content. The same results were obtained by group II. These 5 markers can be applied to marker assisted selection of high potassium tobacco germplasm.

【学位授予单位】：中国农业科学院
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S572

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