Regulatory Sciences, Bayer CropScience, Chesterfield, Missouri, USA.
Environ Toxicol Chem. 2020 May;39(5):1032-1040. doi: 10.1002/etc.4693. Epub 2020 Mar 31.
The commercialization of RNA-based agricultural products requires robust ecological risk assessments. Ecological risk is operationally defined as a function of exposure and adverse effects. Information on the environmental fate of RNA-based plant-incorporated protectants is essential to define routes and duration of exposure to potentially sensitive nontarget organisms. Providing these details in problem formulation helps focus the ecological risk assessment on the relevant species of concern. Postharvest plant residue is often considered to be the most significant route of exposure for genetically modified crops to adjacent aquatic environments. Previous studies have shown that DvSnf7 RNA from SmartStax PRO maize dissipates rapidly in both terrestrial and aquatic environments. Although these studies suggest that direct exposure to DvSnf7 RNA is likely to be low, little is known regarding the fate of DvSnf7 RNA produced in plants after entering an aquatic environment. This exposure scenario is relevant to detritivorous aquatic invertebrates that process conditioned maize tissues that enter aquatic environments. To assess potential exposure to shredders, dissipation of DvSnf7 RNA expressed maize tissue was evaluated following immersion in microcosms containing sediment and water. Concentrations of DvSnf7 RNA in the tissue were measured over a duration of 21 d. The DvSnf7 RNA dissipated rapidly from immersed maize tissue and was undetectable in the tissues after 3 d. Concentrations of DvSnf7 RNA found in tissue as well as calculated water column concentrations were below levels known to elicit effects in a highly sensitive surrogate species, supporting the conclusion of minimal risk to aquatic nontarget organisms. Environ Toxicol Chem 2020;39:1032-1040. © 2020 SETAC.
基于 RNA 的农业产品的商业化需要进行强有力的生态风险评估。生态风险被操作性地定义为暴露和不良影响的函数。关于 RNA 植物整合保护剂在环境中的命运的信息对于确定潜在敏感的非目标生物体的暴露途径和持续时间至关重要。在问题制定中提供这些细节有助于将生态风险评估集中在相关的关注物种上。收获后的植物残留物通常被认为是转基因作物向相邻水生环境暴露的最重要途径。先前的研究表明，来自 SmartStax PRO 玉米的 DvSnf7 RNA 在陆地和水生环境中都迅速消散。尽管这些研究表明，直接暴露于 DvSnf7 RNA 的可能性较低，但对于进入水生环境后在植物中产生的 DvSnf7 RNA 的命运知之甚少。这种暴露情况与处理进入水生环境的条件化玉米组织的碎屑食性水生无脊椎动物有关。为了评估潜在的暴露风险，评估了 DvSnf7 RNA 在含有沉积物和水的微宇宙中浸泡后表达玉米组织的消解情况。在 21 天的时间内测量了组织中 DvSnf7 RNA 的浓度。浸入玉米组织中的 DvSnf7 RNA 迅速消散，在 3 天后组织中无法检测到。在组织中发现的 DvSnf7 RNA 浓度以及计算出的水柱浓度均低于在高度敏感的替代物种中引起效应的已知水平，支持对水生非目标生物体风险最小的结论。Environ Toxicol Chem 2020;39:1032-1040。 © 2020 SETAC。
