Genome Mining and Expression Analysis of Carboxylesterase and Glutathione S-Transferase Genes Involved in Insecticide Resistance in Eggplant Shoot and Fruit Borer, Leucinodes orbonalis (Lepidoptera: Crambidae)

Abstract

The shoot and fruit borer, Leucinodes orbonalis (Lepidoptera: Crambidae) is the major cause of low productivity in eggplant and insecticides being the mainstay of management of L. orbonalis. However, field control failures are widespread due to the evolution of insecticide resistance. Taking advantage of the whole genome sequence information, the present study investigated the level of insecticide resistance and the expression pattern of individual carboxylesterase (CE) and glutathione S-transferases (GSTs) genes in various field collected populations of L. orbonalis. Dose-mortality bioassays revealed a very high level of resistance development against fenvalerate (48.2–160-fold), phosalone (94-534.6-fold), emamectin benzoate (7.2–55-fold), thiodicarb (9.64–22.7-fold), flubendiamide (187.4–303.0-fold), and chlorantraniliprole (1.6–8.6-fold) in field populations as compared to laboratory-reared susceptible iso-female colony (Lo-S). Over-production of detoxification enzymes viz., CE and GST were evident upon enzyme assays. Mining of the draft genome of L. orbonalis yielded large number of genes potentially belonging to the CE and GST gene families with known history of insecticide resistance in other insects. Subsequent RT-qPCR studies on relative contribution of individual genes revealed over-expression of numerous GSTs and few CEs in field populations, indicating their possible involvement of metabolic enzymes in insecticide resistance. The genomic information will facilitate the development of novel resistance management strategies against this pest.

Molecular identification of glutathione S‐transferase genes and their potential roles in insecticides susceptibility of Grapholita molesta

“…Emamectin benzoate (EB), chlorantraniliprole (CT) and lambda-cyhalothrin (LC) are three commonly used synthetic insecticide for controlling moths in the orchard (Liguori et al, 2010). Recently, many pests have developed different degrees resistance to these three insecticides, such as Cydia pomonella (Rodríguez et al, 2010), Pieris rapae (Liu et al, 2017), Heortia vitessoides (Cheng et al, 2018) and Leucinodes orbonalis (Kariyanna et al, 2020). The main biochemical resistance mechanisms of insects are increased metabolism and decreased target sensitivity (Enayati et al, 2005).…”

Pest categorisation of Leucinodes orbonalis

“… Internal feeding in fruit with entry holes sealed make infested fruit difficult to detect unless cut open. Resistance to pesticides has developed within L. orbonalis (Ayam et al., 2016 ; Shirale et al., 2017 ; Kariyanna et al., 2020 ) driven by the frequent application of pesticides (e.g. there can be between 56 and 180 applications during the S. melongena growing season; Chakraborti and Senapati, 2016 ).…”

Current and future prospects of “all-organic” nanoinsecticides for agricultural insect pest management

“…The use of broad-spectrum conventional insecticides, like organochlorines, organophosphates, carbamates, and pyrethroids, has been widespread in agricultural croplands over the past five decades for their immediate effects (Sparks, 2013). However, the indiscriminate and excessive use of these chemicals resulted in a wide range of negative consequences, including eco-framework irregularity (Schäfer et al, 2019;Vašíčková et al, 2019), toxicity to nontarget organisms (Singh and Leppanen, 2020;Teng et al, 2020), and the development of insecticide-resistant pests (Kariyanna et al, 2020;Sparks et al, 2020). In addition to synthetic-chemical pesticides, some organic insecticides have also been recommended to combat insect pests (Lengai et al, 2020;Stankovic et al, 2020).…”