基于鸳鸯染色体的害虫遗传防治新技术的开发

Genetic pest management (GPM) gets increasing attention for its environment friend, sustainablility and other advantages. However most of the GPM technologies have their limitations, such as the well-studied Release of Insects Carrying a Dominant Lethal (RIDL) needs the tetracycline to control the expression of lethal gene during the mass production of the sterile insects, although the application of tetracycline in large amount will inevitably cause antibiotic pollution. In order to solve this problem, we will develop a new technology to produce sterile insects based on the concept of “Yuanyang Chromosome Pair, YYCP”. The Yuanyang chromosome pair is a pair of homologous chromosomes which must coexist in a cell or in the offspring, otherwise, the cell or offspring will die. We’ll first simulates the effect of YYCP with a pair of plasmids in cell line. Then we’ll construct the Drosophila melanogaster transgenic lines with YYCP by two ways: 1. Combination of two pairs of toxin-antitoxin, with toxin1-antitoxin2 genes integration in one chromosome and toxin2-antitoxin1 genes integration in the same locus of another homologous chromosome. 2. Silencing two essential genes at the same time and rescuing one gene in one chromosome and another in another chromosome. The population suppression and population replacement effects will be evaluated by cage studies after the transgenic lines are constructed. The success of this work will greatly help the application of this new technology on other pest control. The concept, principle and construction methods of this technology are all original, which will avoid the patent infringement during commercial application. Furthermore, the application of this technology is not limited to insect control. Other pests and invasive species, such as rodents and Asian carps are also potential controlling targets of this technology.

害虫遗传防治技术因其独特的优势而越来越受到重视。目前主流的害虫遗传防治技术均有其局限性，如研究最多的RIDL技术就需要依赖四环素，而四环素的大量应用会产生环境污染等问题。为解决这些问题，本项目首先提出“鸳鸯染色体”的概念，即一对同源染色体A和B，AB共存则活、分开则死。利用质粒在细胞上成功模拟的基础上，本项目将以果蝇为材料，从两种不同的途径和方案来探索构建鸳鸯染色体的转基因品系：1. 通过两对毒素抗毒素基因交叉组合来实现；2. 通过同时沉默两个必须基因，然后在每一条染色体上各补充一个基因来实现。获得所需转基因鸳鸯染色体品系后，将在笼内评价其抑制种群增长或者种群替代的效果，为这一技术应用于其它害虫的遗传防控做技术储备。该项目从概念、原理到实现方法均具有原创性，为今后的商业应用扫除了专利障碍。同时其应用范围也不局限于害虫防治，对于其它鼠类等有害生物，亚洲鲤鱼等入侵生物的防治也有潜在应用价值。

目前害虫遗传防治技术因其效果持久、环境友好、靶标性专一、安全性高等优点在近年来逐渐被人们关注。其理念与技术手段也不断改善和升级，目前已经存在传统遗传防治技术、释放携带显性致死基因昆虫技术（RIDL）、基因驱动等多种技术，但都存在一定局限性，且非均非我国原创技术。因此，建立一种新的害虫遗传防治技术，且为我国原创的技术，具有十分重要的意义。.本项目提出“鸳鸯染色体”的概念，即一对同源染色体A和B，AB共存则活，分开则死。本研究的主要内容围绕该概念，在果蝇中率先建立这种新的害虫遗传防治技术。以细菌中的毒素抗毒素作为致死基因和挽救基因，通过两对毒素抗毒素基因交叉组合来实现鸳鸯染色体效果。我们通过构建表达毒素的载体，利用显微注射技术得到相应的转基因果蝇品系，通过杂交将相关基因遗传到一只果蝇上。之后通过热激诱导FRT位点间重组，启动毒素基因的表达，得到鸳鸯染色体果蝇品系。目前，已经得到了6种鸳鸯染色体果蝇品系，其中5个品系由于毒素效果太强（品系本身死亡）或太弱（致死率不足），无法实现很好的致死效果。但其中有一个品系与野生型杂交后，后代数量明显低于50%。.鸳鸯染色体果蝇品系致死率效果不佳，主要是由于不同毒素的效果不同和热激诱导表达过程中存在一些随机性。目前经过长期的探索与优化，已经对实验方案进行了较完善的调整。后续会得到新的鸳鸯染色体果蝇品系，理论上来说致死率会有较好的效果。