玉米抗倒伏主效QTL qRsl1的目标基因克隆和功能研究

The stalk lodging resistance of maize is not only one of the key agronomic traits determining corn yield, but also urgently required for mechanical harvesting. However, the intensive study of its genetic architecture is relatively poor in China due to that it is a complex quantitative genetic trait. Our study will fine-map one major QTL qRsl1 of stalk lodging resistance and identify the candidate genes and further characterize qRsl1. Based on preliminary mapping results, a sequential QTL fine-mapping strategy is applied by conducting MAS and phenotyping recombinant-derived progeny with rind penetrometer resistance(RPR) as quantitative evaluation index. With the aid of MAS, the recombinants are screened and identified and their progeny population are generated by backcrossing with recurrent parent. Meanwhile, the progeny population are both genotyped and phenotyped to deduce that if the recombinants carry the donor segment with targeted QTL. Then the physical interval size of qRsl1 is narrowed down based on the results and new recombinants in the narrowed targeted QTL region is selected for backcrossing. Multiple fine-mapping processes is carried out sequentially and finally the fine mapping of the target QTLs are completed with the target QTL region less than 100kb. Subsequently, combining genome resequencing with the transcriptomic analysis of NILs of qRsl1 and transgenic complement assay, the target gene will be finally identified and confirmed. Molecular genetics, biochemistry together with multi-omics based approach are taken to characterize its role in enhancing RPR and unveil the genetics basis and molecular mechanism of stalk lodging resistance in maize and further provide theory evidence and germplasm for maize molecular breeding.

抗倒伏是玉米产量相关的关键性状，也是玉米机械化收获的迫切需求。抗倒伏表现为复杂的数量性状, 深入的遗传学研究十分薄弱。本研究将针对玉米抗倒伏性状的主效QTL qRsl1, 将玉米茎秆穿刺强度作为抗倒伏表型的量化评价指标，在前期QTL初定位基础上，进行基因精细定位和目标基因克隆及功能研究。采用基于重组个体后代表型和基因型测定的连续精细定位方法，将qRsl1限定在<100kb的区间内，完成精细定位。基因组重测序结合qRsl1近等基因系的转录组及转基因功能互补验证，确定并克隆目标基因。利用分子遗传学、生物化学加上各类组学手段，研究qRsl1如何影响茎秆穿刺强度，并进一步解析玉米抗倒伏性状形成的遗传基础和分子机理，为玉米抗倒伏分子育种提供扎实的理论依据和种质材料。

抗倒伏是玉米产量相关的关键性状，也是玉米机械化收获的迫切需求。本研究针对玉米抗倒伏性状的主效QTL qRsl1, 将玉米茎秆穿刺强度作为抗倒伏表型的量化评价指标，在前期QTL初定位基础上，完成了基因的精细定位，区间内包含12个编码基因。通过定量PCR检测12个基因在近等基因系中的表达情况，结合各个不同时期的茎秆穿刺强度，将候选基因范围缩小为4个基因。另外，为了避免极端天气对表型测定产生的影响，重新选择了两个茎秆穿刺强度极端的亲本，并利用高茎秆穿刺强度亲本作为轮回亲本构建群体，同时对他们不同时期的茎秆进行穿刺强度的测定和转录组测序分析，得到了初步的一些结果。