RNAi生物技术作物环境风险评估研究进展

Progress for environmental risk assessments of RNAi-based crops

RNA干涉(RNAi)在昆虫遗传和功能基因研究方面广泛应用。近年来,RNAi被认为是具有应用潜力的害虫防治新方法。具有良好抗虫性状的RNAi生物技术作物已研究成功,预示其商业化应用成为可能。因此,有关RNAi作物的生态风险是商业化应用前人们所关心的问题。要建立RNAi生物技术作物环境安全评价准则,监管者、受益各方及风险评估者必须要了解RNAi理论及其在生物技术领域的应用。科学分析并准确提出RNAi作物的生态风险问题,如非期望的基因沉默、靶外结合或脱靶效应、靶标害虫的抗性、小干涉RNA(si RNA)的环境持久性和不确定性等,并通过研究获得科学数据,将为政府依法监管提供依据。RNAi生物技术作物的环境风险评估主要包括功能基因及其表达特征(如ds RNA序列、长度、表达浓度及沉默效果的持续性等)、杀虫谱及对非靶标生物的影响、环境中的残留问题、功能性状的持续稳定性等。现行的生物技术作物环境风险评估方法和内容需要进一步修改完善,以适应今后RNAi生物技术作物的发展和应用。

RNA interference（ RNAi） has been widely used for genetic research in insects. Recently,RNAi via ingestion was considered as a potential tool for insect control. Several studies demonstrated that targeted insects can be effectively by the ingestion of RNAi-based insect resistant biotech crops with obvious commercial implications. In the meantime,the environmental risks should be carefully considered before the commercial use of RNAi-based crops. To set up an environmental risk assessment framework for RNAi-based biotech crops,the regulatory agencies and stakeholders as well as risk analysts need to be familiar with the science of RNAi and its application to plant biotechnology. Scientific questions need to be answered about unintended gene silencing（ including non-target effects）,off-target binding（ off-target effects）,target resistance,stability and persistence of small interference RNA（ si RNA） in various ecosystems,uncertainties,etc. In comparison of information required in an application to a regulatory agency for a transgenic Bt crop,data collection for RNAi-based insect resistance biotech crops should include the molecular characterization and expression of ds RNA（ i. e. nucleotide sequence,length,the concentration of ds RNA for an optimal silencing and the persistence of the silencing effect）,the potential activity spectrum and the impacts on non-targets,the environmental persistence of small RNA molecules,the persistence of the silencing effect and therefore the efficiency of RNAi as an insect control technique. The accepted environmental risk assessment process will need to be adaptable for analysis of RNAi-based biotech crops,which could prompt the development and production. Filling the numerous knowledge gaps surrounding these risks will improve this predictability.