杀虫剂甲维盐对海洋饵料生物桡足类毒性效应的生理和分子机制研究

Promoting the sustainable development of the marine fishery has become an important measure of our country, strengthening the protection and monitoring of marine fishery waters is one of the important tasks. In the offshore and fishery environment, pesticide pollution is a relatively prominent problem. Emamectin benzoate belongs to the avermectin compound family exhibiting toxicity for nematodes, arthropods, and several other pests. It is widely used in controlling lepidopterous pests in agricultural products as well as in the eradication of fish lice and in fish farming. The low-application rate of the active ingredient needed and broad-spectrum applicability as an insecticide has made emamectin benzoate one of the most used pesticides among farmers domestically and internationally. Several studies have been carried out on the toxicity of emamectin benzoate toward insects and fresh water organisms; however, no research has been reported on the toxicity of this pesticide for marine copepods. Copepods are the most numerous metazoan grazers in the marine ecosystem and conventionally considered as the key trophic linkage between diatom-rich phytoplankton blooms and higher trophic levels such as fish in the coastal waters, and have been used as the essential diets for the larvae of many economically important sea food species. Recently, copepods have received increased attention as possible standardized test species for assessing acute and chronic effects of various chemicals including pesticides, especially the relationships between chemical exposure and sublethal effects, particularly stress gene expression and toxicogenomics. Here we proposed to use marine copepods as the model species to carry out the fundamental physiological and molecular study on the acute and chronic effects of pesticide emamectin benzoate toward marine organisms in the ecosystem. We will study 1) the effect of emamectin benzoate on the grazing behavior of copepods; 2) the effect of emamectin benzoate on the survival, egg reproduction and growth rates, and development of copepods; 3) the effect of emamectin benzoate on gene expression of copepods; 4) assessment of emamectin benzoate on the ecological risk copepod populations. The goal of this project is through the study the acute and chronic toxic effects of emamectin benzoate on the physiology and gene expression of the copepods commonly found in the coastal region of our country, to establish a copepod-based index system to evaluate the toxic effect of emamectin benzoate toward marine ecosystem, thereby provide scientific data and evidences for the environment protection of marine fisheries, pollution control and the related policies and regulations.

促进海洋渔业持续健康发展已成为我国的一项重要举措，加强海洋生态环境保护、强化渔业水域生态环境监测是其中的重要任务。在近海渔业环境中，杀虫剂等农药污染是一个比较突出的问题。甲维盐是一种新型高效杀虫剂，被国内外广泛应用于农业领域，也在渔业病害防治中得到应用，关于其对海洋渔业环境及生物的影响，国外也有一些研究，但国内尚未见报道。本项目拟以海洋桡足类这一重要海洋生物类群为模式生物，开展甲维盐对桡足类急性和慢性毒性的生理学和分子生物学研究。主要包括甲维盐对桡足类摄食、生殖、发育、基因表达等方面的影响，揭示甲维盐对桡足类毒性效应的生理和分子生物学机制，评估其对海洋浮游桡足类种群可能造成的潜在危害，为我国海域中杀虫剂对海洋渔业生态系统的影响提供基础资料，同时为我国的海洋渔业环境保护、污染控制及相关的政策、标准等提供科学依据。

本项目研究了甲维盐对海洋桡足类生理活动的影响，明确了甲维盐对海洋浮游及底栖桡足类存活、摄食、生长、发育、繁殖及种群补充等的抑制作用。首次将哲水蚤桡足类反式剪接前导序列（Spliced leader, SL）应用于研究有机污染物对桡足类毒性效应的分子机制，大大提高桡足类基因表达研究的效率，为研究桡足类在污染物或其它环境因子胁迫下的分子响应机制提供了重要工具。利用SL这一工具，首次获得了桡足类全79种细胞质核糖体蛋白基因的全长cDNA序列，为认识和了解桡足类中参与蛋白质合成的重要功能群奠定了基础。基于全长cDNA序列，筛选并验证了一批荧光定量PCR内参基因的适用性，为研究有机污染物胁迫下桡足类基因表达模式奠定了方法基础。利用RNAseq测序及分析策略，构建天然海水培养、甲维盐急性暴露、天然海水恢复条件下的火腿伪镖水蚤转录组文库，筛选对甲维盐暴露应答的重要功能基因及其表达模式，解析了甲维盐对桡足类毒性效应的分子机制。本项目研究成果为评估甲维盐对海洋桡足类种群可能造成的潜在危害提供基础资料，所获得的火腿伪镖水蚤转录组数据为桡足类相关研究提供了宝贵的基因数据资源，建立的桡足类基因表达研究新方法为探索污染物对桡足类毒性效应的分子机制及应用分子生物标志物监测海洋污染物提供了理论依据和方法参考。