植物基因重组频率的遗传调控

在农作物育种过程中，新品种的产生主要依赖于杂交后代优良基因的聚合，它们间的重组频率将直接关系到育种的选择效率。重组频率既是一重要的遗传理论问题，也是决定育种效率高低的应用问题。目前对于如何提高重组频率还缺乏行之有效的对策，要打破不良连锁只有靠无限制地扩大育种选择群体，严重制约了优良基因的聚合和新品种选育的进程。本课题拟在多年来一直从事水稻减数分裂调控分子机理研究的基础上，借助已建立的重组相关突变体材料基础和优良的细胞学研究平台，以水稻为模式作物发展可特异指示交叉发生位置的细胞学标记；系统研究水稻重组抑制因子的功能，创造它们的新等位变异，充分释放抑制因子对重组形成的抑制作用；努力寻找可提高重组频率的重组促进因子，最终实现水稻重组频率的遗传改良。通过这些研究工作，一方面将研究成果有效运用到水稻育种实践当中，同时也为其它作物的遗传改良提供借鉴，切实解决农作物分子育种现行的技术瓶颈。

In crop breeding program, to put more desired genes in the same genetic background is essential for developing good varieties. However, due to the low recombination frequency near the desired genes, it is pretty difficult to break the linkage between the desired genes and its linked genes with unwanted traits, leading to great challenges to the traditional breeding programs. So far, the only way to break the close linkage relies on the unlimited adding populations in the segregated progeny. Therefore, to find an efficient way increasing the recombination frequency becomes more urgent for both traditional and molecular breeding.. Meiosis is a highly conserved process in life cycles of all sexually reproductive organisms. It facilitates the maintenance of stable chromosome number of a species and more importantly produces genetic variation in gametes, which in turn promote genetic and phenotypic variation in its offspring. In most organisms, a stable connection is established by crossovers (COs). COs not only ensure the proper homologous segregation, but create new combinations of alleles leading to increased variation. The number and distribution of COs are tightly controlled. If multiple COs occur along a homologous pair, they are more evenly spaced than would be expected by chance known as interference. In our previous study, about 30 genes related to rice meiosis have been cloned and their biological functions have been well characterized. Therefore, a good platform including genetic resources for homologous recombination mutants as well as solid facilities for cytological observation system has been set up, giving us a great chance to manipulate the recombination frequency in rice. . In this proposal, we are going to focus on the following aspects: to develop a cytological maker system for CO identification; to reveal the molecular mechanism of CO suppression and create new alleles to effectively repress the CO suppression; and to identify new factors may activate CO formation. By making great efforts on these targets, we may find an efficient way to increase the recombination frequency in rice molecular breeding. Nevertheless, we may also extend the knowledge effectively working rice to the whole crop breeding programs.