<p class="Body"><strong>Expression profiles of glutathione S-transferases genes in semi-engorged </strong><strong><em>Haemaphysalis longicornis</em></strong><strong> (Acari: Ixodidae) exposed to <em>Cymbopogon citratus</em> essential oil</strong></p>

Abstract

Glutathione S-transferases (GSTs) are phase II detoxification enzymes, which function via combining with pesticidal molecules and catalyzing the conjugation of molecules by thiol of glutathione, so as to protect tissues from oxidative stress damage. In the tick Haemaphysalis longicornis, glutathione S-transferases (HlGST and HlGST2) have been previously identified. However, the relationship between the transcription of glutathione S-transferases and the essential oil treatment in ticks remains unexplored. Hence, in the present study, the transcription profiles of HlGST and HlGST2 mRNAs were evaluated in H. longicornis after exposure to Cymbopogon citratus essential oil. At 24 h post-exposure of H. longicornis to different sublethal concentrations of C. citratus essential oil, there was significant difference (P = 0.0001) in the transcription of HlGST. Tukey’s test showed that HlGST was significantly induced after treatment with 1% C. citratus essential oil (P = 0.0002); whereas no significant difference (P = 0.3551) was detected after treated by 2% C. citratus essential oil. No significant difference (P = 0.4555) in the transcription of HlGST2 between the treatment and the control group of 50% ethanol. Nevertheless, the down-regulation of HlGST2 in the treatment groups versus the untreated control group was not significant (P = 0.1208). The above results imply that the essential oil can modulate the expression of GST mRNA, therefore, further understanding of the underlying mechanisms of the GST at the molecular level could contribute to the development of effective control measures for ticks and tick-borne diseases.

<p class="Body"><strong><em>Cymbopogon citratus</em></strong><strong> essential oil-induced ultrastructural &amp; morphological changes in the midgut, cuticle &amp; Haller’s organ of the tick <em>Haemaphysalis longicornis</em> (Acari: Ixodidae)</strong></p>

“…Lemongrass essential oil has shown pesticidal properties against mosquitoes, flies, and the larvae and adults of Rhipicephalus microplus (Chauhan et al 2016;Manh et al 2020;Sheziyna et al 2020). Additionally, our previous investigation demonstrated the acaricidal effects of lemongrass essential oil on the mortality and external morphology of H. longicornis and revealed lethal concentrations (LC 50 ) of 29.21, 28.18, 28.06 mg/mL for the adults, nymphs, and larvae, respectively (Agwunobi et al 2020a), and also its effect on the expression profiles of genes of the detoxification enzyme glutathione s-transferases in H. longicornis (Agwunobi et al 2020b). The present study evaluated the ultrastructural and morphological alterations induced by the essential oil of lemongrass on the midgut, integument, and the Haller's organ of the unfed adult H. longicornis tick with the purpose to aid the further understanding of the acaricidal potentials of lemongrass essential oil.…”

Interactive Gene Expression Between Metarhizium anisopliae JEF-290 and Longhorned Tick Haemaphysalis longicornis at Early Stage of Infection

“…For this reason, various methods using biological control agents have recently been studied. Cymbopogon citratus essential oil has a relatively high mortality rate in longhorned ticks (Agwunobi et al, 2020). Another report showed that the antlion Euroleon coreaus could become a new predator for the ticks (Nwanade et al, 2020).…”