转基因水稻花粉逃逸风险的防控策略

基因工程作物与其近源野生种之间的基因流可能产生非预期的环境风险。通过引入与目的基因紧密连锁、对近源野生种不利而对作物有利的基因是减少转基因作物向其野生种进行基因水平转移（horizontal gene transfer HGT）风险的有效措施。
复旦大学生态与进化生物学系教授，国家转基因生物安全委员会环境安全组委员卢宝荣教授及其团队通过人工构建microRNA 和反义RNA技术，沉默栽培水稻的种子落粒性基因SH4，进而降低水稻-杂草杂交后代的种子落粒性。研究发现，在种植转基因杂交后代的水稻田中落粒种子的数量显著减少，而转基因水稻和非转基因水稻在产量相关的农艺性状方面则无显著差异。可见，沉默种子落粒性基因可以有效降低由于水稻和近缘杂草间的基因流而造成的环境效应风险。此外，该策略也可应用于杂草稻的防控。杂草稻的危害日益严重，并受到农业科学家的广泛关注，4月5日和5月26日莱肯生物分别报道了杂草稻进化机制的最新研究进展，这些研究成果对杂草稻的防控具有理论指导意义。
利用遗传工程技术调控转基因对杂草的选择有利性是转基因遗传调控（transgenicmitigation , TM) 的主要研究内容，随着分子遗传学研究的深入，已有不少个性状有望用于转基因遗传调控，这些性状除了本文报道的落粒性之外，还有二次休眠，矮生性等。然而采用该策略控制“超级杂草”仍存在风险，即TM性状和转基因性状的相互分离以及TM性状的突变失活，但实际上，紧密连锁性状突变或交换的频率是极低的，约为10-5~10-7。因此，转基因遗传调控可以在一定程度上降低 “超级杂草”产生的风险，而不是完全避免。

Transgenic Research. Published Online: 19 May 2017
Reduced weed seed shattering by silencing acultivated rice gene: strategic mitigation for escaped transgenes

Authors
Huanxin Yan, Lei Li, Ping Liu, et al.
Ministry of Education Key Laboratory for Biodiversity and Ecological Engineering,Department of Ecology and Evolutionary Biology Fudan University Shanghai China

Abstract
Transgene flow from a genetically engineered(GE) crop to its wild relatives may result in unwanted environmental consequences. Mitigating transgenes via introducing a gene that is disadvantageous to wild relatives but beneficial to crops, and istightly-linked with the target transgenes, may provide a promising solution to limit the spread of transgenes in wild/weedy populations. Here we demonstrate a novel system with significantly reduced seed shattering in crop-weed hybrid descendants by partially silenced expression of the seed-shattering gene SH4 incultivated rice, using artificial microRNA and antisense RNA techniques.Accordingly, fewer seeds were found in the soil of the field plots where transgenic hybrid lineages were grown. However, no differences in productivity-related traits were detected between GE and non-GE cultivated rice. To silence seed-shattering genes provides a useful strategy to reduce the potential environmental impacts caused by transgene flow from commercial GE rice to weedy rice, in addition to the control of weedy rice.


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