基于质谱成像技术的氯虫苯甲酰胺-丙氨酸乙酯在玉米中时空分布研究

The key to reducing pesticide dosage and increasing pesticide efficiency is improving the targeting ability and utilization of pesticides. Guided pesticides can be accumulated to the sites of plant diseases and insect pests, facilitating the precise application of pesticides. The preliminary results showed that the phloem and xylem translocation of guided insecticide, alanine ethyl ester-chlorantraniliprole conjugates (CAP-Ala), were greatly improved. In addition, CAP-Ala has a comparable insecticidal activity as commercial pesticides, such as chlorantraniliprole. Thus, CAP-Ala is the potential novel guided pesticide. However, the key scientific problems, such as the transport, distribution, accumulation rules of CAP-Ala, as well as whether the accumulation site is consistent with the pest damage site, after absorbed by plants, need to be answered. In this proposal, we will take maize as the object, and pinpoint the spatial distribution and targeted accumulation law of CAP-Ala in maize using label-free mass spectrometry imaging techniques, verifying the consistency of the targeted accumulation sites and insect pest sites of CAP-Ala in maize. On this base, the variation of content and distribution of CAP-Ala, in the sites of plant diseases and insect pests as a function of time can be obtained using mass spectrometry imaging and liquid chromatography techniques. In addition, the initial accumulation and duration time of the effective concentration will be acquired. This project is expected to provide the reference for the development of guided pesticides with directed translocation and accumulation. Moreover, it will offer a theoretical basis for the precise application of pesticides.

如何提高农药靶向性和农药利用率是实现农药减量增效的核心问题。导向农药可在植物体内向病虫害为害部位定向积累，达到农药的精准施用。前期研究发现，氯虫苯甲酰胺-丙氨酸乙酯偶合物（CAP-Ala）在韧皮部和木质部的输导性显著提高，并具有与商品化农药氯虫苯甲酰胺相当的内吸杀虫活性，是潜在的新型导向农药。但是CAP-Ala被吸收后，如何在植株中转运、分布及积累？积累部位与害虫为害部位是否一致？这些关键科学问题有待探究。本项目拟以玉米为研究对象，利用无标记可视化质谱成像技术，获得CAP-Ala在植株不同组织中的空间分布及定向积累规律，明确其在玉米植株中定向积累部位与害虫为害部位是否相一致；在此基础上，结合质谱成像和色谱技术，探究CAP-Ala在害虫为害部位积累含量及分布随时间的变化规律，获得其有效浓度的初始积累时间与持效时间。本研究将为创制定向积累的农药提供参考，为农药的精准施用提供理论依据。

如何提高农药靶向性和农药利用率是实现农药减量增效的核心问题。导向农药可在植物体内向病虫害为害部位定向积累，达到农药的精准施用。前期研究发现，氯虫苯甲酰胺-丙氨酸乙酯偶合物（CAP-Ala）在韧皮部和木质部的输导性显著提高，并具有与商品化农药氯虫苯甲酰胺相当的内吸杀虫活性，是潜在的新型导向农药。但是CAP-Ala被吸收后，如何在植株中转运、分布及积累？积累部位与害虫为害部位是否一致？这些关键科学问题有待探究。本研究将质谱成像技术用于导向农药在植株体内输导及累积的可视化检测，首次揭示了由载体介导的导向农药在植物体内的动态输导机制，为深入探讨农药的吸收、分布、代谢和排泄（ADME）过程提供了新思路。研究发现，CAP-Ala新型农药在菜心叶片的输导速率比氯虫苯甲酰胺本体提高了约5倍，这主要是因为CAP-Ala具有氨基酸导向基团，可充分调动了植物自身相关的转运蛋白来转运，使其与母体相比具有更高的韧皮部输导性。同时，CAP-Ala从根部被玉米吸收后会向上转运输导，在玉米茎和叶片病虫害为害部位定向输导和积累，达到农药的精准施用及减量增效。通过CAP-Ala培养玉米幼苗24 h后，在茎叶就可以达到有效浓度的初步积累量，到48 h时CAP-Ala在茎叶中已高效富集，其持效时间和累积量可有效对玉米螟和草地贪夜蛾等靶标害虫的取食进行防治。同时CAP-Ala不会对玉米籽粒萌发过程中的代谢物含量产生影响，有望成为新的候选农药用于进一步地推广应用。本研究为靶向农药创制及其精准高效施用提供了理论依据。在本项目的资助下，共发表学术论文13篇（其中一区6篇、二区2篇）。同时，以本项目第一标注在Nano Research、Science of the Total Environment等期刊发表系列研究成果8篇，授权国家发明专利2项，培养毕业学术型硕士研究生2名。