转基因栽培稻与野生稻杂交超亲分离后代的适合度及其对进化影响

The potential ecological risks caused by transgene introgression into crop wild relative species have aroused tremendous concerns over environmental biosafety issues worldwide. In the process of transgene introgression, the transgene with selective advantage may bring new adaptability to wild relatives, meanwhile, the transgressive segregation in hybrid progeny may also provide plenty of variations for natural selection of the wild relatives. However, little is known about the interaction between transgenes and transgressive segregation in crop-wild and crop-weed hybrid progenies, as well as their combined effect on fitness and evolutionary potential of the crop wild relative, which may bring unpredicted ecological risks. We plan to use the multiple-generation hybrid progenies between herbicide-resistant transgenic rice and common wild rice to study the fitness and evolutionary effect of transgressive segregation in the process of transgene introgression, including: 1) determining the number of proportion and fitness advantage of transgressive segregation populations in growth and fecundity related traits; 2) revealing the dynamic change and genetic stability of transgressive segregation populations among different hybrid generations; 3) assessing the impact of transgene on the number of proportion and fitness advantage of the transgressive segregation; 4) analyzing the impact of transgressive segregation populations on the introgression and spread of transgenes in wild rice population. Based on the knowledge generated from above fitness study, we could analyze the interaction between functional genes and transgressive segregation and its impact on the evolutionary potential of wild rice populations during the hybridization and introgression process, to reveal the relevant mechanisms on ecological risks caused by transgene flow.

转基因渐渗到作物野生近缘种可能带来的生态风险是全球备受关注的环境生物安全问题。在转基因渐渗过程中，具有选择优势的转基因可以为野生近缘种的进化带来新的适应性，同时杂交产生的超亲分离群体也为野生近缘种的进化提供了丰富的选择材料。转基因与超亲分离在杂交后代中如何相互作用并共同影响作物野生近缘种的适合度和进化潜力，从而导致一定的生态风险？对此则了解甚少。本项目组将利用抗除草剂转基因栽培稻与普通野生稻杂种多世代分离群体，研究杂交超亲分离后代群体的适合度及进化影响，包括：1）在生长与繁殖相关性状上产生超亲分离群体比例及其适合度优势；2）超亲分离群体随杂种世代的动态变化及遗传稳定性；3）具有选择优势的转基因对于超亲分离群体的影响；4）超亲分离群体对转基因渐渗和扩散的影响。基于上述适合度研究结果，分析转基因和超亲分离的相互作用及其对野生稻群体进化潜力的影响，从而揭示转基因逃逸导致生态风险的相关作用机制。

转基因渐渗到作物野生近缘种可能带来的生态风险是全球备受关注的环境生物安全问题。转基因渐渗过程中，具有选择优势的转基因可以为野生近缘种的进化带来新的适应性，同时杂交产生的超亲分离群体也为野生近缘种的进化提供了丰富的选择材料。转基因与超亲分离在杂交后代中如何相互作用并共同影响作物野生近缘种的适合度和进化潜力，从而导致一定的生态风险？对此则了解甚少。本研究以栽培稻-野生稻多世代杂种后代为研究体系，通过建立一套超亲分离的检测指标，包括产生超亲的性状，超亲分离的产生频率（超亲群体比例）以及超亲分离的强度（相对于亲本的优势程度），在这些群体中研究epsps抗除草剂转基因对于栽培稻与野生稻杂交过程中产生超亲分离的影响及其进化意义。通过分析epsps抗除草剂转基因栽培稻与野生稻F3-F5代晚世代杂种后代适合度相关性状的表现，我们发现晚世代杂种后代在所有性状上都产生了一定频率的超亲分离，超亲分离的频率和强度在不同性状之间差异显著；转基因显著提升了晚世代杂种后代在生殖相关性状上的超亲分离频率；转基因和超亲分离分别为杂种后代带了了一定的性状优势，而转基因与超亲分离在个别杂种组合的生殖性状上表现出了的更为显著的叠加优势；转基因和超亲分离的叠加优势在个别组合中显著高于转基因和超亲分离单独带来的优势。以上研究结果表明，具有选择优势的转基因可以显著增加栽培稻与野生稻杂种后代中超亲分离的产生频率，并通过转基因和超亲分离的叠加优势产生一定比例的、具有较强进化潜力的极端类型，进一步促进转基因的渐渗，影响野生稻群体的进化潜力，从来带来潜在的环境生物安全问题。