水稻ZEP1基因在重组频率控制过程中的机理及应用研究

In plant breeding, plant breeders attempt to break the linkage between the desired genes and unwanted genes. Scientists have been looking for genes that regulate recombination process so as to disclose the recombination regulatory mechanism and finally gain control over the process. In previous study, we have identified ZEP1, a transverse filament protein, and found that the number of crossovers increased markedly in zep1 mutant. So, ZEP1 is the first identified gene in plants that can increase recombination frequency. The finding makes it probable to investigate the regulation of recombination frequency in plants from a genetic perspective. In this project, we will analyze the relationship between recombination frequency and the DNA-binding affinity of ZEP1. Also, we intend to screen proteins that interact with ZEP1 using several different methods. By studying the function of ZEP1-interacting genes, we seek to explore their coordinated regulation mechanism. Additionally, transgenic plants that show a significantly increased recombination frequency will be selected and used for future plant breeding.

在植物育种过程中，摆脱不良基因与优良基因的连锁一直是育种学家们期盼的目标。为此，科学家们一直在试图寻找控制重组频率的基因，以揭示重组频率调控的机理，进而实现重组交换的可控性。本实验室在水稻中克隆了横丝蛋白编码基因ZEP1，细胞学观察发现zep1突变体中交换频率有了显著的增加，所以ZEP1是植物中分离的第一个能增加重组交换频率的基因，该发现为在基因层次上开展重组频率调控的研究提供了可能。本项目拟对ZEP1蛋白不同位点进行修饰，探寻ZEP1的DNA结合能力与重组频率的联系；同时我们将用多种方法同时筛选与ZEP1相互作用的蛋白，阐明互作基因的功能，揭示各基因协同调控重组频率的机制，并选择可显著提高重组频率的转基因株系用于育种潜力分析。

在作物种间和种内蕴藏着大量的优良性状基因，但是这些优良基因的转移通常会受到有限的遗传重组频率以及不良基因连锁的影响。所以提高遗传重组频率、打破不良基因与优良基因间的连锁一直是育种家们追求的目标。本项目通过对水稻联会复合体的弱等位突变体研究发现：部分突变联会复合体可以平均提高重组频率至原来的 1.8倍左右，在重组冷点处最高可提高至原来的 4.2倍左右。结合遗传学分析以及细胞学观察表明这类提高的遗传重组主要通过 I型重组交换途径形成。通过本项目的实施首次实现了在农作物中提高遗传重组频率的目标。