Physiological and biochemical response of Aedes aegypti tolerance to Bacillus thuringiensis

† Songqing Wu, Wei Wu, Xiaoli Zhu and Zhaoxia Liu contributed equally to this work.

ABSTRACT

Bacillus thuringiensis subsp. israelensis (Bti) represents the only eco-friendly bio-degradable insecticide for mosquito-borne disease control. Our research aims to identify if mosquito detoxification enzymes play an important role in Bti tolerance mechanisms in the dengue vector, Aedes aegypti. Several enzymes, such as amylase, cytochromes P450, Na⁺/K⁺-ATPase, acetylcholinesterase, protease and glutathione S-transferase (GST) were analysed and level of activity determined in Ae. aegypti larvae after Bti treatment. Bti exposure significantly increased the level of amylase (183.2%) as well as the activity of cytochromes P450 (177.5%), and Na⁺/K⁺-ATPase (142.9%). On the other hand, there was a decrease of 8.6% and 11.4% in acetylcholinesterase and GST activity, and no significant effect in the total level of protease activity. We suggest that the variation in amylase, cytochromes P450, Na⁺/K⁺-ATPase, acetylcholinesterase, protease and GST activity may be associated with the Bti insecticidal mechanism. This study provides the basis of detoxifying enzymes in Bti tolerance.

KEYWORDS:

• Bacillus thuringiensis
• Aedes aegypti
• detoxifying enzymes
• mosquito tolerance

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

† Songqing Wu, Wei Wu, Xiaoli Zhu and Zhaoxia Liu contributed equally to this work.

Additional information

Funding

This study was supported by National High Technology Research and Development Programme 863 [Grant No. 2011AA10A203], Project of Fujian-Taiwan Joint Center for Ecological Control of Crop Pests [Minjiaoke (2013) 51], the Special Fund for Forestry Research in the Public Interest of China [Grant No. 201304401], the United Fujian Provincial Health and Education Project for Tackling Key Research [Grant No. WKJ-FJ-25], National Natural Science Foundation of China [Grant No. 31301724, No. 31201574 and No. 31401802], Education Department Foundation of Fujian Province Distinguished Young Scholars in Universities of Fujian Province [Grant No. JA12092], Science Fund for Distinguished Young Scholars of Fujian Agriculture and Forestry University [Grant No. xjq201203], Key Projects of Fujian Provincial Department of Science and Technology [No. 2011|N5003 and No. 2013N0003], Natural Science Foundation of Fujian Province [Grant No. 2013J01079], Programme for New Century Excellent Talents in Fujian Province [JA13089], the Special Fund for Grain Research in the Public Interest of China [Grant No. 201313002-3], the Special Fund for Key Construction Project of Fujian Agriculture and Forestry University [Grant No. 6112C035003], National Undergraduate Training Programme for Innovation and Entrepreneurship [Grant No. 201510389013, No.201510389018, No. 201510389023, No. 201510389025, No. 201510389028, No. 201510389101 and No. 201510389173].