玉米第1染色体耐旱主效QTL区段基因发掘与功能解析

As a very complex quantitative trait, the genetic mechanism of drought tolerance is always a puzzle around the genetics and breeding scientists. In this program, the drought-tolerant major QTL (quantitative trait loci)region is firstly fine-mapped by polymorphic SSR (simple sequence repeat) and SNP (single nucleotide polymorphism) markers with a big RIL (recombinant inbred lines) population based on our previous studies. Furthermore, genomic re-sequencing of this regime are conducted, and candidated functional genes and SNP variations are identified to do linkage and association mapping with drought-tolerant introgression lines and inbred lines. Finally, identified drought-tolerant genes and variations are verified with bilogical experiments. The results will be great significance to elucidate the genetic mechanism of drought tolerance and development of new materials.

耐旱性是一个复杂的数量性状，通过对耐旱主效QTL（quantitative trait loci）进行基因发掘和功能解析对于推动抗性机理诠释和培育耐旱新材料非常重要。本项目在原有的工作基础上，利用RIL(recombinant inbred lines)大群体，对玉米第1染色体上耐旱主效QTL区段通过区段内多态性SSR（simple sequence repeat）和SNP(single nucleotide polymorphism)标记进行精细定位，进而通过基因组区段重测序，发掘耐旱功能候选基因和耐旱等位变异，利用耐旱高代回交导入系和自交系群体，对精细定位后耐旱主效QTL进行连锁和关联定位，确定耐旱功能基因及其耐旱等位变异，进而对其分子生物学功能进行遗传解析和功能验证。研究结果对于耐旱遗传解析和耐旱新材料创制具有重要意义。

作物耐旱机理复杂，多基因控制，耐旱分子育种一直缺乏有用的基因资源及功能标记进行辅助选择。本项目利用不同玉米遗传材料多年多点干旱处理下的玉米耐旱相关性状的表型数据，结合高通量SNP芯片的基因型数据，通过联合关联和连锁分析的方法确定在玉米的的第1染色体主效QTL内与耐旱性相关的肌动蛋白解聚因子基因ZmADF5(Actin Depolymerizing Factor 5)；进一步通过转录组测序分析和转基因拟南芥验证说明ZmADF5基因促进根的伸长，干旱胁迫下促进玉米开花期提前，避开严重缺水，具有调控玉米耐旱性的功能；酵母杂交研究推测ZmADF5基因受蛋白激酶CKII调控玉米LOB(Lateral Organ Boundaries)基因进行耐旱性调节；发掘并验证了PZE-101047611参与玉米耐旱性调控，可以作为玉米耐旱功能标记。研究结果推动了复杂数量性状的遗传分析在生产育种上的实际应用。