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ARS Home » Plains Area » Kerrville, Texas » Knipling-Bushland U.S. Livestock Insects Research Laboratory » Research » Publications at this Location » Publication #141703
Title: STATUS AND FUTURE PROSPECTS FOR MOLECULAR DIAGNOSIS OF ACARICIDE RESISTANCE IN BOOPHILUS MICROPLUS

Author
item Guerrero, Felicito
item Pruett Jr, John

Submitted to: Trends in Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2003
Publication Date: 3/15/2003
Citation: Guerrero, F., Pruett Jr., J.H. 2003. Status and future prospects for molecular diagnosis of acaricide resistance in Boophilus microplus. Trends in Entomology. 3:97-103.

Interpretive Summary: Boophilus microplus is an economically significant tick parasite of cattle, responsible for severe negative impacts on animal health and cattle producer profitability in many regions of the world. We have begun the development of rapid molecular-based assays for specific acaricide resistance-associated genes to facilitate the identification of acaricide resistant populations of B. microplus. One of these assays is a PCR-based assay to detect a specific sodium channel gene mutation that is associated with resistance to permethrin. A number of Mexican strains of B. microplus have been genotyped by this assay that tests individual ticks at any life stage with results available in a few hours. We are also cloning specific genes involved in resistance to organophosphates. These genes code for acetylcholinesterase, the target of OPs and carboxylesterases, a family of enzymes capable of metabolizing OPs. We are using this information to devise a battery of DNA-or ELISA-based assays capable of rapidly genotyping individual ticks for pyrethroid and OP resistance-associated genes.

Technical Abstract: Boophilus microplus is an economically significant tick parasite of cattle, responsible for severe negative impacts on animal health and cattle producer profitability in many regions of the world. We have begun the development of molecular-based assays for specific acaricide resistance-associated genes to facilitate the identification of acaricide resistant populations of B. microplus. We have devised a PCR-based assay to detect a specific sodium channel gene mutation that is associated with resistance to permethrin. A number of Mexican strains of B. microplus have been genotyped by this assay that tests individual ticks at any life stage with results available in a few hours. Additionally, a specific metabolic esterase with permethrin-hydrolyzing activity has been purified and its gene coding region cloned. A mutant allele of this esterase gene has been found, though the mutation seems to provide only a low level of additional permethrin resistance compared to that provided by the wild type allele. We are also cloning specific acetylcholinesterase (AChE) and carboxylesterase genes that appear to be involved in resistance to organophosphates (OP). We are devising a battery of DNA-or ELISA-based assays capable of rapidly genotyping individual ticks for pyrethroid and OP resistance-associated genes.