Abstract:

Objective To observe the larvicidal activities of transgenic cyanobacteria with CryIVD gene of Bacillus thuringiensis subsp. israelensis against different larval instars of Culex pipiens pallens. Methods Transgenic cyanobacteria with CryIVD gene of Bacillus thuringiensis subsp. israelensis were cultured in large numbers and were then dried and stored. The larvicidal activities of transgenic cyanobacteria stored for different periods were determined against different larval instars of Cx. pipiens pallens.Results The dried and stored transgenic cyanobacteria demonstrated a high toxicity to Cx. pipiens pallens larvae, and the longer the dried ones were stored, the lower their toxicity was. Compared with fresh ones, the stored transgenic cyanobacteria had slightly decreased larvicidal activity. They killed over 50% of larvae of different instars in 48 hours at concentration of 105 cells/ml. At a concentration of 106 cells/ml, transgenic cyanobacteria stored for one year, two years, and three years showed similar larvicidal activities, resulting in no significant differences in mortality rate of Cx. pipiens pallens larvae (F=9.32, P>0.01), but there was significant difference in the mortality rate when comparison was made between the transgenic cyanobacteria stored for one year and three years at a concentration of 105 cells/ml (F=101.21, P<0.01). Conclusion The cryIVD gene of Bacillus thuringiensis subsp. israelensis and larvicidal activity of stored transgenic cyanobacteria remain stable, and the stored transgenic cyanobacteria provide a convenient way for use in the field.

Key words: Bacillus thuringiensis subsp. israelensis, CryIVD gene, Culex pipiens pallens, Stored transgenic cyanobacteria, Larvicidal activity

摘要：

目的 观察苏云金杆菌CryIVD转基因贮存藻对不同龄期淡色库蚊幼虫的杀灭效果。方法 大量培养工程藻,干燥后保存,应用不同时间的贮存藻作用于不同龄期淡色库蚊幼虫。结果 干燥贮存的工程藻数年后仍有较高的杀蚊毒效,尽管杀蚊毒效较新鲜工程藻有所下降,但在10⁵个/ml数量级不同龄期的幼虫仍有50%以上死亡。对不同龄期淡色库蚊幼虫杀灭效果比较表明,1～3年贮存藻3组比较,在10⁶个/ml数量级浓度的蚊幼虫死亡率差异无统计学意义(F=9.32, P>0.01),而贮存1年组和3年组在10⁵个/ml数量级浓度及以下,死亡率差异有统计学意义(F=101.21,P<0.01)。结论 转基因蓝藻在干燥贮存情况下仍能保持毒蛋白的稳定遗传和杀幼虫作用,为今后的现场应用提供更方便的选择。

关键词: 苏云金杆菌以色列变种, CryIVD基因, 淡色库蚊, 贮存藻, 杀蚊毒效