Analysis of sequence variations in the GABA gated chloride gene associated with resistance to fipronil in Rhipicephalus (Boophilus) microplus ticks from Argentina

SARLI, MACARENA; NAVA, SANTIAGO; MOREL, NICOLÁS; TORRENTS, JORGELINA

Ticks and Tick-borne Diseases

Elsevier

Año: 2022 vol. 13

1877-959X

This study aimed to evaluate the sequence variations of the GABA-Cl gene of Rhipicephalus (Boophilus) microplusticks from Argentina with different resistance levels to fipronil. Genomic DNA was obtained from engorged females(n = 50) of fipronil-susceptible and resistant tick field populations from five localities in northernArgentina. Tick populations were tested for fipronil resistance by in vitro larval packet test. DNA encoding aminoacid residues 264?360 of the GABA-Cl was amplified by PCR. PCR products were sequenced and the translatedamino acid sequences were aligned and compared among each other and with sequences of the GABA-Clbelonging to the Brazilian and Uruguayan reference strains fipronil-susceptible (Mozo) and resistant (RFSanand Juarez). All the GABA-Cl amino acid sequences obtained from the R. microplus specimens from Argentinawere identical, regardless of the fipronil resistance-susceptibility status of each population. Mutations present inGABA-Cl sequence of RFSan and Juarez strains were not present in any of the populations from Argentinaanalyzed. These results indicate the failure of this gene as a molecular marker of resistance to fipronil, at least inthe R. microplus populations from northern Argentina.