Resistance in the Genus Spodoptera: Key Insect Detoxification Genes

Abstract

The genus Spodoptera (Lepidoptera: Noctuidae) includes species that are among the most important crop pests in the world. These polyphagous species are able to feed on many plants, including corn, rice and cotton. In addition to their ability to adapt to toxic compounds produced by plants, they have developed resistance to the chemical insecticides used for their control. One of the main mechanisms developed by insects to become resistant involves detoxification enzymes. In this review, we illustrate some examples of the role of major families of detoxification enzymes such as cytochromes P450, carboxyl/cholinesterases, glutathione S-transferases (GST) and transporters such as ATP-binding cassette (ABC) transporters in insecticide resistance. We compare available data for four species, Spodoptera exigua, S. frugiperda, S. littoralis and S. litura. Molecular mechanisms underlying the involvement of these genes in resistance will be described, including the duplication of the CYP9A cluster, over-expression of GST epsilon or point mutations in acetylcholinesterase and ABCC2. This review is not intended to be exhaustive but to highlight the key roles of certain genes.

Metabolic functional redundancy of the CYP9A subfamily members leads to P450-mediated lambda-cyhalothrin resistance in Cydia pomonella

“…55 Thereafter, several studies have documented that over-expression of CYP9As is associated with insecticide resistance. 56 To further investigate the roles of CYP9A genes in lambda -cyhalothrin resistance, the relative expression of CYP9A120 , CYP9A121 , and CYP9A120 was compared between resistant and susceptible populations. All CYP9A genes were overexpressed in ZW_R, a field population that has evolved a moderate level of resistance to lambda -cyhalothrin.…”

Spodoptera frugiperda Sf9 cells as a model system to investigate the role of detoxification gene expression in response to xenobiotics

“…CYP9A31 was the most induced gene following xenobiotic exposure. It is part of a cluster that contains 12 CYP9As, with CYP9A32 and CYP9A30 on either side of its position in the genome ( Hilliou et al., 2021 ). We chose to heterologously express these three P450s and to investigate their capacity to metabolize diverse coumarin fluorescent probe substrates.…”

Molecular Oscillator Affects Susceptibility of Caterpillars to Insecticides: Studies on the Egyptian Cotton Leaf Worm—Spodoptera littoralis (Lepidoptera: Noctuidae)

“…The proposed target in this case are genes usually related to both development and metabolism in general [ 79 , 80 , 81 , 82 ]. Among the latter, knockout of these involved in the inactivation and removal of xenobiotics from the body is of special importance, as they are shaping the susceptibility of insects to insecticides [ 83 , 84 , 85 , 86 ]. The use of RNAi to increase the susceptibility of insects to insecticides is also logical and used, for example, in strains that have developed resistance to these compounds [ 87 , 88 , 89 ].…”