Effects of Sublethal Doses of Methyl Benzoate on the Life History Traits and Acetylcholinesterase (AChE) Activity of Aphis gossypii

Abstract

Safer alternatives to synthetic pesticides are essential for sustainable agriculture. Methyl benzoate (MB) is a volatile essential oil found in several plants. Recent reports of the toxicity of MB to arthropod pests suggest that MB may be a useful alternative insecticide. The present study assessed the effects of a sublethal concentration of MB (LC30, 0.22%) on the life history and reproductive characteristics of the cotton aphid, Aphis gossypii Glover, in both a treated parental generation (F0) and untreated progeny (F1). MB treatment significantly decreased longevity and fecundity in both the F0 and F1 generations, and prolonged the developmental duration of each immature instar of the F1 generations, compared with controls. The intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (R0) of the F1 generation were significantly reduced, compared to controls. The mode of action of MB is not known, but in aphids treated with LC30 MB, the activity of the enzyme acetylcholinesterase (AChE) decreased by more than 65%, compared with untreated controls. AChE activity was rapidly inhibited within 1 h, and remained inhibited for 6 h after in vivo exposure to MB. Moreover, molecular docking analysis revealed that MB had a strong affinity with the catalytic site of AChE, with a binding energy value of −6.2 kcal/mole. Our results suggest that MB targets AChE, and that a sublethal dose of MB can have adverse transgenerational effects on cotton aphids.

Potential of Cucurbitacin B and Epigallocatechin Gallate as Biopesticides against Aphis gossypii

“…Biopesticides (natural products) have emerged as a better alternative for pest control [31]. CucB and EGCG are the major secondary metabolites of host plants cucurbits and cotton, which are the host plant of two typical biotypes of the notorious agricultural pest aphid-CU and CO [14,15,38].…”

“…EGCG strongly and directly inhibits telomerase [24] and affects metabolism in mammals and insects [25,26]. Cytochrome P450 monooxygenases (P450s), glutathione S-transferases (GSTs), carboxylesterase (CarE), acetylcholinesterase (AchE), and acid phosphatase (ACP) are involved in xenobiotic metabolism of insects [27][28][29][30][31]. However, the effects of CucB and EGCG on population-level fitness and xenobiotic metabolism enzymes of cotton-melon aphids have never been adequately characterized.…”

Methyl Benzoate as a Promising, Environmentally Safe Insecticide: Current Status and Future Perspectives

“…Additionally, MBe exhibited hydrophobic interactions with at least five AChE amino acids [122]. These results suggest that MBe is potentially targeting AChE at a molecular level.…”

“…Recently, Feng and Zhang [14] revealed that MBe had a significant impact on D. suzukii development. Mostafiz et al [122] found that a sublethal dose of MBe (LC 30 = 0.22%) significantly reduced the fecundity and longevity of the aphid A. gossypii in the treated parental generation (F0) and their untreated progeny (F1). Moreover, MBe prolonged the developmental duration of each immature instar of the F1 generation compared with the controls.…”

“…Thus, this enzyme is often designated as the target molecule for organophosphate and carbamate insecticides [126]. Most recently, Mostafiz et al [122] revealed that AChE activity in cotton aphids, A. gossypii, treated with MBe (0.22%) was reduced by 65% compared to the control. A molecular-docking program was also used to simulate how MBe and AChE would interact with each other.…”