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Insect nicotinic
acetylcholine receptors (nAChRs): Important amino acid
residues contributing to neonicotinoid insecticides
selectivity and resistance
Zewen Liu*, Xiangmei Yao
and Yixi Zhang
Key Laboratory of Monitoring and Management of Plant
Disease and Insect, Ministry of Agriculture, Nanjing
Agricultural University, Nanjing 210095, China.
*Corresponding
author. E-mail:
jemunson@njau.edu.cn. Tel/Fax: 0086-25-84399051
Accepted
9 December, 2008 |
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Nicotinic
acetylcholine receptors (nAChRs) are ligand-gated ion
channels which mediate fast cholinergic synaptic
transmission in insect and vertebrate nervous systems. The
great abundance of nAChRs within the insect central nervous
system has led to the development of insecticides targeting
these receptors, such as neonicotinoid insecticides.
Neonicotinoid insecticides act selectively on insect nAChRs,
accounting at least in part for the selective toxicity to
insects over verte-brates. Some important amino acid
residues in insect nAChR α and β subunits contribute to
neonicotinoid insecticides selectivity, including important
residues in loop C, the region loop B to the N-terminus and
loop B-C interval of insect α subunit, and important
residues in loop D, E and F of insect β subunit. Important
residues contributing to neonicotinoid insecticides
selectivity may also contribute to the resistance to these
insecticides, if they mutate to other residues identical or
similar to the corresponding residues in vertebrate
subunits. The first point mutation Y151S has been identified
in insect α subunit loop B to be associated with
neonicotinoid insecticides resistance, which decreased
neonicotinoid insecticides affinity remarkably, but showed
little effects on insect nAChRs normal function.
Key
words:
Nicotinic acetylcholine receptor, neonicotinoid
insecticides, selectivity, resistance. |
