黑麦矮杆基因Ddw4精细定位

As an important cereal crop and germplasm resources for common wheat genetic and breeding improvement, rye has great value for studying. The exploration and utilization of dwarf gene is always an important issue in crop high yield research. But so far there is no dwarf gene in rye was fine mapped. In previous work, we found a new dwarf gene in rye material PI613129. The dwarfing trait is controlled by one pair of incomplete dominance dwarf genes. It is sensitive to gibberellic acid. This new dwarf gene has a strong ability to reduce plant height in rye. But it is appropriately in wheat genetic background. In this proposal, The F2 segregating populations were used to construct the lowest and highest bulk. We plan to locate this dwarf gene and develop linkage molecular markers by using rye 600K SNP chip to respectively analyze the lowest bulk and highest bulk. Then we construct wheat//dwarf rye/tall rye F1 segregating big populations to fine mapping this dwarf gene and obtaining candidate chromosome region. The candidate dwarf gene will be screened out according to gene annotation in candidate chromosome region. Combine the differential expression genes between tall and dwarf plant by performing transcriptome analyses further screen the candidate gene. This study will lay the basis for subsequent gene cloning, dwarfish mechanism and utilization of dwarfing resources.

黑麦作为一种重要的谷类作物以及普通小麦遗传改良的种质资源，对其研究具有重要价值。矮杆基因的发掘、利用一直是作物高产研究的一个重要课题。目前黑麦中还没有一个矮杆基因被精细定位。前期工作发现在黑麦材料PI613129中存在一个新的矮杆基因，其矮生性状受一对不完全显性的矮杆基因控制，且对赤霉素敏感。该矮杆基因在黑麦中具有较强的致矮能力，但在小麦背景中致矮能力适中。本项目拟通过F2群体构建极端高、矮池，用黑麦600K芯片对该矮杆基因进行初定位并开发连锁分子标记，再通过普通小麦//矮杆黑麦/高杆黑麦构建F1分离群体进行精细定位并获得候选区段，通过候选区段内基因注释筛选可能候选基因，再结合转录组分析高、矮杆差异表达基因，进一步确定候选矮杆基因。本研究将为后续的矮杆基因克隆、致矮机制研究以及矮源利用奠定基础。

株高是作物的重要农艺性状，植株过高容易引起倒伏，进而影响产量及品质。发掘和利用矮杆、半矮杆基因对保障粮食安全具有重要意义。普通小麦作为重要的粮食作物，矮化育种一直是高产研究的重要课题之一。目前，普通小麦中发掘的矮杆基因在育种利用上存在矮源单一和环境敏感等问题。因此，发掘新矮源、阐明矮化机制、评估育种价值是小麦高产研究的重要内容。前期我们在黑麦种质PI613129中发掘到一个矮杆基因Ddw3，该矮杆基因在普通小麦背景中能显著降低株高，在普通小麦矮化育种中具有重要的潜在利用价值。本项目通过黑麦高、矮杆材料全基因组重测序数据开发分子标记，利用多态性标记在4个小麦-黑麦双单倍体群体中分别构建遗传连锁图，将矮杆基因Ddw3精细定位于黑麦1R染色体长臂，位于标记AR-26和AR-31之间。该标记分别对应于黑麦Lo7参考基因组和Weining v1参考基因组1R上约462.28~465.05Mb和595.38~601.03Mb之间，物理距离约为2.0Mb（包含20个基因）和5.6Mb（包含41个基因）。进一步通过构建Ddw3杂合的1R/1B代换系（2n=42）次级分离群体，将Ddw3定位于标记AR-21和AR-64之间（约37.2Mb）的物理区间，初步验证了上述定位结果。候选区段内基因分析表明，Ddw3的候选基因均不是目前已报道的赤霉素生物合成和信号转导途径相关基因，其矮化机制可能涉及一种新的分子机制。该研究为Ddw3的图位克隆、分子机制解析及育种利用奠定了良好基础。