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

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