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United States Department of Agriculture

Agricultural Research Service

Title: Serial analysis of gene expression in the southern cattle tick following acaricide treament of larvae from organophosphate resistant and susceptible strains

Authors
item Guerrero, Felix
item Bendele, Kylie
item Chen, Andrew
item Li, Andrew
item Miller, Robert
item Pleasance, E - CMSGS CENTRE-VANCOUVER CA
item Varhol, R - CMSGS CENTRE-VANCOUVER CA
item Rousseau, M - MCGILL UNIV-QUEBEC CANADA
item Nene, V - TIGR-ROCKVILLE MD

Submitted to: Insect Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 7, 2006
Publication Date: February 1, 2007
Citation: Guerrero, F.D., Bendele, K.G., Chen, A.C., Li, A.Y., Miller, R.J., Pleasance, E., Varhol, R., Rousseau, M.-E., Nene, V.M. 2007. Serial analysis of gene expression in the southern cattle tick following acaricide treament of larvae from organophosphate resistant and susceptible strains. Insect Molecular Biology. 16(1):49-60.

Interpretive Summary: Organophosphate resistant and susceptible tick larvae from laboratory strains of the southern cattle tick, Rhipicephalus (Boophilus) microplus were exposed to low doses of the organophosphate (OP) acaricide, coumaphos. The technique of serial analysis of gene expression (SAGE) was used to analyze differential gene expression in response to OP treatment and to compare the responses of OP-treated and -untreated resistant and susceptible ticks. The aim was to identify specific genes which are either activated or deactiviated upon tick exposure to coumaphos. A database of gene sequences exists and is designated the B. microplus Gene Index (http://www.tigr.org/tdb/tgi). This database was used as a resource of DNA sequences to help determine the function and identity of genes whose abundance changed in response to acaricide exposure. A second technique, called relative quantitative RT-PCR, was used to confirm the differential expression results from the gene quantification experiments. Of particular interest is a gene which was identified as a cytochrome P450 EST in the Gene Index. This gene's product was more abundant in untreated OP resistant larvae compared to untreated OP susceptible larvae. This gene's product was also more abundant in OP resistant larvae treated with OP compared to OP susceptible larvae treated with OP. Cytochrome P450s form a large gene family, many of whose members are involved in detoxification of various chemicals and whose abundance increases under exposure to toxins. Because this specific P450 from . microplus appears to be more common in OP resistant or OP treated ticks, a role in pesticide resistance is possible for this gene.

Technical Abstract: Organophosphate resistant and susceptible tick larvae from laboratory strains of the southern cattle tick, Rhipicephalus (Boophilus) microplus were exposed to low doses of the organophosphate (OP) acaricide, coumaphos. Serial analysis of gene expression (SAGE) was used to analyze differential gene expression in response to OP treatment and to compare the responses of OP-treated and -untreated resistant and susceptible ticks. A B. microplus Gene Index (http://www.tigr.org/tdb/tgi) was used as an EST database to identify genes which corresponded to SAGE tags whose abundance changed in response to acaricide exposure. Relative quantitative RT-PCR was used to confirm the differential expression results from the SAGE experiments. Of particular interest is a SAGE tag which corresponds to a cytochrome P450 EST in the Gene Index which was more abundant in untreated OP resistant larvae compared to untreated OP susceptible larvae. This SAGE tag was also more abundant in OP resistant larvae treated with OP compared to OP susceptible larvae treated with OP.

Last Modified: 9/1/2014