致倦库蚊对球形芽孢杆菌杀蚊Mtx1毒素的抗性及抗性特征的研究

发布时间：2018-05-14 18:11

本文选题：致倦库蚊 + Mtx1　；参考：《中国科学院研究生院（武汉病毒研究所）》2005年硕士论文

【摘要】：Mtx1 毒素是球形芽孢杆菌(Bacillus sphaericus)在营养体生长阶段产生的一种杀蚊毒素,其作用机制和杀虫活性不同于杀蚊二元毒素,具有潜在的应用价值。本研究主要从Mtx1 毒素的杀虫谱、Mtx1 毒素对致倦库蚊的后致死作用、诱导致倦库蚊(Culex quinquefasciatus)产生抗性及抗性蚊虫的抗性特性方面进行了研究。生物测定表明,Mtx1 毒素对受试的几种鳞翅目昆虫几乎没有毒性,但对白纹伊蚊表现出了中等程度的毒性,对敏感和二元毒素抗性致倦库蚊表现出了高度的毒性。表达Mtx1 毒素的E-TH21 冷冻粉剂对敏感致倦库蚊品系SLCq 和二元毒素抗性品系RLCq1/C3-41 和RLCq2/IAB59 的LC_(50)值分别为0.508、0.854 和0.675mg/L。结果证明,Mtx1 毒素在控制或减缓致倦库蚊对二元毒素的抗性方面具有潜在的应用价值。 Mtx1 不仅对目标蚊幼虫具有特异性的毒杀作用,同时也具很强的后致死作用。分别以亚致死浓度(LC_(10)、LC_(30)、LC_(50)、LC_(70)、LC_(90)和LC_(98))的Mtx1 毒素和二元毒素制剂处理2-3 龄致倦库蚊幼虫48 小时后,经处理的存活幼虫在各生长阶段都表现出了明显的延续死亡和损伤现象,羽化前死亡率分别为85.0%、97.5%、98.6%、99.5%、100%、100%和23.1%、44.4%、61.6%、83.2%、95.1%、100%。Mtx1 毒素较二元毒素对致倦库蚊有更强的后致死作用。在致倦库蚊对Mtx1 毒素的抗性研究中,我们用高剂量的Mtx1 毒素制剂对致倦库蚊进行了30 代的筛选,得到了抗Mtx1 毒素的低水平抗性品系RLCq4/Mtx1,同敏感蚊虫比较,其抗性水平约为223.2 倍。该品系对苏云金芽孢杆菌以色列亚种(B. thuringiensis subsp. israelensis)和球形芽孢杆菌LP1-G 和47-6B 不产生交互抗性,对IAB59 菌株表现出了部分交互抗性,对二元毒素产生菌C3-41 和B-CW-1 产生高水平的交互抗性。另外,我们比较了敏感的SLCq 和抗性的RLCq1/C3-41、RLCq4/Mtx1 品系在生物适合度方面的差异。结果表明,两种抗性品系RLCq1/C3-41 和RLCq4/Mtx1 的繁殖力略有降低,但这两种品系雌蚊的寿命却明显长于SLCq 品系。
[Abstract]:Mtx1 toxin is a kind of insecticidal toxin produced by Bacillus sphaericus in the growth stage of vegetative body. Its action mechanism and insecticidal activity are different from that of binary toxin, so it has potential application value. In this study, the post-lethal effect of Mtx1 toxin on Culex quinquefasciatus and its resistance to Culex quinquefasciatuswere studied. The results showed that the resistance of Culex quinquefasciatus and the resistance of Culex quinquefasciatus to Culex quinquefasciatus were studied. Bioassay showed that Mtx1 toxin had little toxicity to several Lepidoptera insects, but showed moderate toxicity to Aedes albopictus, and high toxicity to Culex pipiens quinquefasciatus with sensitive and binary toxin resistance. The values of E-TH21 frozen powder expressing Mtx1 toxin to sensitive Culex pipiens quinquefasciatus strain SLCq and binary toxin resistant strain RLCq1/C3-41 and RLCq2/IAB59 were 0.508 mg / L and 0.675 mg / L, respectively. The results showed that Mtx1 toxin had potential application value in controlling or slowing the resistance of Culex pipiens quinquefasciatus to binary toxin. Mtx1 not only has a specific toxicidal effect on the larva of the target mosquito, but also has a strong postlethal effect. After 48 hours of treatment of 2-3 instar Culex quinquefasciatus larvae with Mtx1 toxin and binary toxin, respectively, the survival larvae of Cucurbitus quinquefasciatus treated with sublethal concentration (LC10 / LC1 / 30 / LC50 / LC50) and LC98 (respectively) showed a significant continuation of death and injury at all stages of growth. The death rate before Eclosion was 85.0% and 98.65%, and 99.50.100% and 23.1%, 44.4% and 61.6%, respectively. The toxin had a stronger post-lethal effect on Culex pipiens quinquefasciatus than the binary toxin. In the study of the resistance of Culex pipiens quinquefasciatus to Mtx1 toxin, we screened Culex quinquefasciatus with high dose of Mtx1 toxin for 30 generations and obtained a low level resistant strain RLCq4 / Mtx1, which was about 223.2 times more resistant to Mtx1 toxin than that of sensitive mosquito. The strain did not produce cross resistance to Bacillus thuringiensis Israeli subspecies B. thuringiensis subsp. israelensis) and Bacillus sphaeroides LP1-G and 47 6B, but showed partial cross resistance to IAB59 strain and high level cross resistance to binary toxin producing bacteria C3-41 and B-CW-1. In addition, we compared the differences in biological fitness between sensitive SLCq and resistant RLCq1 / C3-41 / RLCq4 / Mtx1 strains. The results showed that the fecundity of RLCq1/C3-41 and RLCq4/Mtx1 decreased slightly, but the lifespan of female mosquitoes was longer than that of SLCq.
【学位授予单位】：中国科学院研究生院（武汉病毒研究所）
【学位级别】：硕士
【学位授予年份】：2005
【分类号】：R384

【参考文献】