Extensive gene duplication of acetylcholinesterase associated with organophosphate resistance in the two-spotted spider mite
Version of Record online: 25 NOV 2009
© 2009 The Authors. Journal compilation © 2009 The Royal Entomological Society
Insect Molecular Biology
Volume 19, Issue 2, pages 195–204, April 2010
How to Cite
Kwon, D. H., Clark, J. M. and Lee, S. H. (2010), Extensive gene duplication of acetylcholinesterase associated with organophosphate resistance in the two-spotted spider mite. Insect Molecular Biology, 19: 195–204. doi: 10.1111/j.1365-2583.2009.00958.x
- Issue online: 3 MAR 2010
- Version of Record online: 25 NOV 2009
- First published online 25 November 2009.
- gene duplication;
- organophosphate resistance;
- Tetranychus urticae
Monocrotophos-resistant two-spotted spider mites (TSSMs), Tetranychus urticae, are known to possess three mutations on the acetylcholinesterase (AChE) gene (Tuace) that are involved in target site insensitivity. Cross-strain comparison of three strains (highly resistant AD, moderately resistant PyriF and susceptible UD strains) revealed that resistant strains have relatively more Tuace copies than the UD strain and that the levels of transcript were directly proportional to copy numbers. AChEs from the AD and PyriF strains had similar Vmax values to those of AChE from the UD strain but increased Km and reduced kcat constants, suggesting that the mutated, resistant form of AChE may carry a fitness cost. Relative copy numbers of Tuace in field populations varied from 2.4 to 6.1, correlating well with their levels of resistance (r2= 0.895). These results are suggestive of the involvement of Tuace gene duplication in resistance. Thus, monocrotophos resistance in TSSMs appears to have evolved through a combination of mutation accumulation and extensive gene duplication.