籼稻镉累积数量性状位点的定位

发布时间：2019-03-03 09:55

【摘要】：随着工农业的发展,环境污染日益加剧,尤其是土壤重金属污染,已经严重威胁到粮食安全和国民健康。据统计,我国耕地污染面积已达五分之一,镉是最重要的污染物之一。水稻是我国最主要的粮食作物,通过食用来自污染土地的大米将有毒的重金属镉摄入人体会引起很大的健康问题,相对于土壤置换或种植高富集镉的植物等减少土壤中镉含量的方法而言,我们可以通过改良稻米的质量并培育低镉累积的水稻品种来避免这个问题。水稻对镉的吸收和积累是多位点控制的数量性状,不同品种对镉的积累存在差异,因此本研究针对华南地区重金属污染严重的现状,对这一地区的籼稻品种采用数量性状位点定位来发掘镉积累的相关基因,期望能用于分子育种。我们将200余个籼稻品种种在韶关市练塘村与华南植物园的含镉实验田中,共于2014年、2015年、2016年先后种植五批并检测了其中三批水稻籽粒中镉的含量,三次水稻籽粒镉含量范围分别为0.031-0.153 mg/kg、0.034-0.162 mg/kg、0.211-3.516 mg/kg。对三次检测中的相同品种水稻两两做相关性分析,发现前两次水稻籽粒镉含量之间的相关性比二者与第三次之间的要强,可能是由于前两次是在相同地点种植的原因。然后用种植的不同品种籼稻叶片做了全基因组重测序,根据重测序结果对籽粒镉含量与基因组中的单核苷酸多态性做关联分析,共找到可能与籼稻中镉含量累积有关的39个单核苷酸多态性位点。最后根据单核苷酸多态性与数量性状位点的连锁不平衡对显著SNP前后50kb进行连锁不平衡分析,对显著SNP前后20kb范围内的基因进行注释并对候选基因进行GO富集分析,最终筛选得到了可能与籼稻镉累积相关的9个数量性状位点。本实验重复性不是很好,需要进行多次检测分析,另外还需进行后续实验对所得基因位点进行验证以确定其是否真正与镉累积相关。
[Abstract]:With the development of industry and agriculture, environmental pollution, especially soil heavy metal pollution, has seriously threatened food security and national health. According to statistics, the polluted area of cultivated land in our country has reached 1/5, cadmium is one of the most important pollutants. Rice is the most important food crop in our country. It will cause great health problems by consuming rice from polluted land and ingesting toxic heavy metal cadmium into human body. We can avoid this problem by improving the quality of rice and cultivating rice varieties with low CD accumulation compared with the methods of reducing CD content in soil such as soil replacement or planting high CD-rich plants. The uptake and accumulation of cadmium in rice is a quantitative character controlled by many sites, and the accumulation of cadmium in different varieties is different. Therefore, this study aims at the serious pollution of heavy metals in South China. Quantitative trait loci were used to locate genes related to cadmium accumulation in indica rice varieties in this area, which was expected to be used in molecular breeding. We planted more than 200 indica rice varieties in experimental fields containing cadmium in Liantang Village, Shaoguan City, and South China Botanical Garden in 2014 and 2015, and tested cadmium content in three batches of rice grains in 2016. The range of cadmium content in grain of three times rice was 0.031 脳 0.153 mg/kg,0.034-0.162 mg/kg,0.211-3.516 mg/kg., respectively. It was found that the correlation between CD content in the grain of the first two times was stronger than that between the two and the third time, which might be due to the fact that the first two times were planted in the same place. Then the whole genome was resequenced using the leaves of different varieties of indica rice. According to the results of resequencing, the relationship between the CD content in grain and the single nucleotide polymorphism in the genome was analyzed, and the relationship between CD content in grain and single nucleotide polymorphism in genome was analyzed. A total of 39 single nucleotide polymorphisms (SNPs) were found which may be related to cadmium accumulation in indica rice. According to the linkage disequilibrium between single nucleotide polymorphism and quantitative trait loci, the linkage disequilibrium of 50kb before and after significant SNP was analyzed, and the genes in the 20kb range before and after significant SNP were annotated and the candidate genes were analyzed by GO enrichment. Finally, 9 quantitative trait loci which may be related to cadmium accumulation in indica rice were obtained. The repeatability of this experiment is not very good, so it needs to be detected and analyzed many times. In addition, the gene loci need to be verified by subsequent experiments to determine whether it is really related to cadmium accumulation or not.
【学位授予单位】：仲恺农业工程学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53;S511.21

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