基于植物体内黑芥子酶的硫苷导向农药靶向释放与积累

Pesticides with good phloem mobility can have more efficacious function in protecting crop, especially in controlling sucking insects and vascular pathogens. Most of pesticides are immobile, but the addition of a glycosyl group can confer phloem mobility to them. The conjugates can accumulate in specific parts of the plant which were damaged by pest via the involvement of sugar transporters and bioactive by endogenous β-glucosidases to release pesticide and control pests. This method has achieved the targeted accumulation and liberation of pesticide. In order to improve the study, we inspire by the glucosinolate–myrosinase defense system to tether the mobility-conferring glucose to the pesticide via a sulfur atom to a (Z)-N-hydroximinosulfate ester. A series of guided glucosinolate-pesticides recognized by myrosinases have been synthesized. Their phloem mobility, distribution property and metabolism will be systematically evaluated, and the mechanism of targeted liberation and accumulation will be investigated by using transcriptome technology. This research integrates the pesticide and plant defense system to lead toward intellectualized and targeted development of pesticide, and can help reduce pesticide application dosage and improve pest control efficiency.

具有韧皮部输导性的农药能更有效的保护作物，特别是在防治刺吸式口器害虫和维管束病害方面优势明显。大多数农药不具备韧皮部输导性，但将其与糖基偶合后，能够借助植物体内的糖转运蛋白向作物嫩芽等害虫为害部位积累，再通过植物体内的β-葡萄糖苷酶水解释放出来，实现农药的定向输导、积累和释放。本课题拟借鉴植物自身的硫代葡萄糖苷-黑芥子酶防御体系，将农药与葡萄糖通过磺酸肟的方式偶合，构建能被植物体内黑芥子酶特异性水解的硫代葡萄糖苷农药分子，研究其输导性、分布部位与病虫害为害部位的吻合性、与黑芥子酶的结合特性及降解规律，阐明其在植物体内的吸收转运机理及靶向释放机制，达到农药使用与植物防御体系相统一，引领农药向智能化、靶向化方向发展，实现农药的减量增效。

硫代葡萄糖苷-黑芥子酶防御体系在十字花科植物的抵御病虫害为害中起到重要作用。本项目通过将导向农药与其相结合，1）设计合成了硫苷香豆素导向农药分子，通过爪蟾卵母细胞-双电压钳技术证明了其能够被硫苷转运蛋白转运，植株体实验证明其具有韧皮部输导性，同时对小菜蛾的生长发育具有明显抑制作用；2）通过保守序列分析和分子对接，结合点突变，研究了硫苷转运蛋白底物特异性，硫苷转运蛋白SER92可能在底物识别中起到重要作用；3）筛选得到了一个对硫苷转运蛋白的转运具有明显抑制的抑制剂，能够显著降低韧皮部液中硫苷含量；4）通过体外酶解实验、分子对接和分子动力学研究了导向农药分子与β-葡萄糖苷酶的降解机制，证明了连接臂长度会影响其水解率；5）建立了质谱成像平台，通过MALDI-MS可以准确检测含硫的农药分子，为硫苷导向农药分子检测提供有利支撑。本项目的实施，为导向农药的理论发展提供了重要参考，为防治病虫害提供新的思路。通过开展上述工作内容，发表论文11篇，申请专利4项。