水稻叶形建成调控网络及其理想株型育种利用研究

Leaf morphogenesis is one of the important components of rice plant type. Study on its development and regulation network is the key to leaf shape improvement. Advanced recombinant inbred line populations were derived from 9311 and Pei'ai 64S. With the determination of leaf shape, the whole genome deep sequencing of all population lines and construction of near-isogenic lines，major QTL affecting leaf shape has been targeted for fine mapping and isolation，research was made on correlation analysis of QTL interaction and yield. After cloning leaf morphogenesis such as SLL1 and SRL1, double/multi mutants were constructed to analyze the regulation and interaction of leaf morphogenesis in rice growth at the molecular level. Induced mutation was applied to rolled leaf mutant sll1 and srl1 through reverse mutation to obtain rolled leaf suppressor mutant with normal leaves. With map-based cloning, suppressing genes Sup-SLL1 and Sup-SRL1 were isolated and regulation relation of upstream and downstream genes was analyzed. Assisted by traditional breeding and modern biological technology, rice leave shape was improved. The result of the research will further elucidate the regulation network of leaf morphogenesis in rice, provide new approaches and new materials for rice super-high yield molecular design breeding which has ideal plant achitecture by moulding its leaf shape, and will help to understand the mechanism regulating leaf morphology.

叶形是水稻株型重要组成部分，其发育遗传调控网络研究是叶形改良的关键所在。利用9311与培矮64S构建的高代重组自交系群体，结合株系叶片表型测定、群体单株全基因组深度测序和构建近等基因系，进行叶形主效QTL的精细定位与分离，研究不同QTL间的互作关系及与产量的关联分析。在完成SLL1、SRL1等多个叶形基因克隆的基础上构建双（多）突变体，利用基因芯片和生物信息学，分析不同叶形调控基因在叶片发育中的分子机理及相互作用机制；采用回复抑制突变方法，诱变处理卷叶突变体sll1和srl1，获叶片回复平展的卷叶抑制突变体，并通过图位克隆技术分离抑制基因Sup-SLL1和Sup-SRL1，分析上下游基因的调控关系。借助传统育种与现代生物技术，改良水稻叶形，开展理想株型超级稻分子设计育种利用研究。研究结果将进一步阐明水稻叶形发育的遗传调控网络，同时为超级稻选育奠定良好的理论基础和材料基础。

摘要：水稻叶形与植株伸展姿态、光合作用和抗倒、抗逆密切相关。水稻产量潜力的增加主要得益于因株型改良而带来的光合作用持续时间和光合叶面积的增加。虽然目前近20个叶形调控基因先后克隆，但基因数量还相对偏少，难以系统的从分子水平上揭示水稻叶片形态发育的分子调控网络。. 本项目采用9311、PA64S、日本晴等已完成全基因组测序的水稻品种构建重组自交系群体、染色体片段置换系、近等基因系和叶形突变体材料，开展叶形基因/QTL克隆、功能研究及其育种价值验证。我们完成了2个与产量相关的叶形调控主效QTL qLSCHL4和qFLW7的克隆及功能研究，并对其在水稻产量育种价值进行验证。 结果表明来自不同籼粳遗传背景的等位基因在功能上存在较大差异，在93-11籼稻中聚合来自日本晴的qLSCHL4等位基因，能使93-11最高增产18.70%；同样，在日本晴背景中聚合来自9311的qFLW7等位基因，能使日本晴叶面积增大，提高净光合效率，产量增加10.05%。结果表明，挖掘和聚合更多类似qLSCHL4、FLW7高产等位基因进行高产超级稻分子设计育种，优化株型和库-源关系，实现超级稻产量新突破，为解决世界粮食安全问题提供新思路。同时，我们利用白脉反卷、白化窄叶等叶形突变体和光敏感卷叶突变体，完成水稻叶脉发育调控基因OsARVL4、NAAL1和光敏感卷叶基因PSL1克隆；利用卷叶突变体sll1二次EMS诱变构建双突变体，分离克隆了与SLL1基因互作的半显性卷叶基因ERL1，并对其在叶形调控网络中的互作关系开展了前期研究。这些叶形基因的克隆为后期解析水稻叶形建成分子调控网络提供了基因资源，为理想株型和高产超级稻的选育奠定材料基础和理论指导。. 通过本项目的实施，共完成5个水稻叶形基因/QTL克隆；创建具理想株型的高产种质材料15份；获得分子标记专利2项，申请基因专利1项。在Molecular Plant、Rice、Plant Growth Regulation和Chinese Science Bulletin等国内外刊物上发表研究论文6篇，其中SCI论文5篇，累计影响因子达15分以上。依托本项目共培养博士研究生1名、硕士研究生2 名。