水稻叶和籽粒镉积累机制及QTL定位研究

Research on Mechanism and QTL Mapping Associated with Cadmium Accumulation in Rice Leaves and Grains

水稻是我国最重要的粮食作物,挖掘控制水稻叶和籽粒镉积累的关键基因,阐明水稻镉积累和转运的遗传机制,为培育籽粒低镉积累的水稻品种、保障粮食安全和人类健康提供依据。通过离子组学技术系统分析中国栽培稻核心种质资源209个品种籽粒的离子谱,鉴定出一批铁、锌等高富集以及镉低积累的水稻品种,并选择籼稻(indica)品种花楸03和粳稻(japonica)品种SKC进行进一步研究。结果表明,尽管这两个品种对镉的耐受性和吸收能力无显著差异,花楸03籽粒和地上部分的镉积累量显著高于SKC,而铁、锌等含量差异不显著。以花楸03和SKC为亲本构建了包含137个单株的双单倍体(doubled haploid,DH)群体,共检测到8个控制镉在叶和籽粒中积累的QTL,分别位于第2、3、4、7、8、10和11染色体上,能解释10.6%-39.4%的表型变异。其中第3染色体上检测到的控制镉向籽粒转运的QTL qGCd3定位在RM6266-RM2334,LOD(limit of detection)值和贡献率分别为3.81和39.4%,此处可能存在一个控制镉向籽粒转运的重要基因。

Rice is the most important staple food in China,thus mining the key genes controlling cadmium(Cd)accumulation in rice leaves and grains and clarifying the genetic mechanism of Cd accumulation and transport may provide the basis for breeding rice varieties with low cadmium accumulation and ensuring food security and human health.Inomics screening was performed to systemically profile ionic spectrum in the grains of 209 rice varieties from the Rice Core Germplasm cultivated in China.The accessions with differential cadmium and/or iron(Fe)/zinc(Zn)accumulations were identified,from which indicia cultivar HQ03 and japonica cultivar SKC were selected for further study.Results showed that there was no significant difference in cadmium tolerance and uptake between the two varieties,and Cd accumulations in the HQ03 shoots and grains were significantly higher than those in SKC,while no difference in Fe,Zn,etc.Using a doubled haploid(DH)population derived from HQ03 and SKC of 137 individuals,8 quantitative trait loci(QTL)controlling Cd accumulation in the leaves and grains were identified on chromosome 2,3,4,7,8,10 and 11,accounting for 10.6%-39.4%of the phenotypic variance detected.Among them,qGCd3,controlling Cd transport to grains,was delimited in the interval of RM6266-RM2334 on chromosome 3,with an LOD(limit of detection)value of 3.81 and a phenotypic contribution of 39.4%,indicating that an important gene controlling cadmium transport to grain may exist here.