Nuclear factor erythroid‐derived 2–related factor 2 activates glutathione S‐transferase expression in the midgut of Spodoptera litura (Lepidoptera: Noctuidae) in response to phytochemicals and insecticides

Abstract

Detoxication enzymes play an important role in insect resistance to xenobiotics such as insecticides and phytochemicals. We studied the pathway for activating the expression of glutathione S-transferases (GSTs) in response to selected xenobiotics. An assay of the promoter activity of GST epsilon 1 (Slgste1) of Spodoptera litura led to the discovery of a cis-regulating element. An antioxidant response element was activated in response to indole-3-carbinol (I3C) and chlorpyrifos (CPF) and was able to bind with the xenobiotic sensor protein nuclear factor erythroid-derived 2-related factor 2 (SlNrf2). SlNrf2 and Slgste1 were responsive to reactive oxygen species induced by I3C and CPF in a S. litura cell line, as well as in S. litura midguts. SlNrf2 RNA interference (RNAi) reduced the message RNA levels of Slgste1 and the peroxidase activity of GSTs in response to I3C, xanthotoxin, CPF and deltamethrin. SlNrf2 RNAi and inhibitor treatment of GST activity decreased the viability of I3C-treated cells. These results indicate that SlNrf2 activates the expression of GSTs in response to oxidative stresses caused by exposure to xenobiotics.

Transcriptome analysis of Spodoptera litura reveals the molecular mechanism to pyrethroids resistance

“…GST3, which was annotated as GST1 and showed positive correlation with the resistance level among the four resistant populations, was reported to possess high binding activities to deltamethrin and high peroxidase activity [11]. SlNrf2 was reported to bind with the promoter of GST1 and regulate the peroxidase activity in response to the stress induced by deltamethrin and other xenobiotics [29] [30]. In S. exigu, the expression of UGT42B5, UGT40D5, UGT33J3 and UGT33T3 were reported to be induced by lambda-cyhalothrin [31].…”

Molecular Cloning and Characterization of Five Glutathione S-Transferase Genes and Promoters from Micromelalopha troglodyta (Graeser) (Lepidoptera: Notodontidae) and Their Response to Tannic Acid Stress

“…However, little information is available on the GST promoter in insects. Chen et al showed that the Slgste1 promoter played an important role in regulating gene expression in response to phytochemicals and insecticides in Spodoptera litura [ 17 ]; Hu et al reported that in the promoter region of the SeGST gene from Spodoptera exigua , cis -acting elements responded to chlorpyrifos and cypermethrin [ 18 ]. However, there have been no previous reports on the GST promoter in Notodontidae insects.…”

“…To understand molecular mechanisms, many promoters have been identified. For example, the Slgste 1 promoter was found to play an important role in regulating gene expression in response to phytochemicals and insecticides in Spodoptera litura [ 17 ]; in the promoter region of the SeGST gene from Spodoptera exigua , cis -acting elements responded to chlorpyrifos and cypermethrin [ 18 ].…”

The glutathione S-transferase (PxGST2L) may contribute to the detoxification metabolism of chlorantraniliprole in Plutella xylostella(L.)

“…The insect GSTs play key roles in the metabolism of xenobiotic compounds and can enhance insecticide resistance by binding to insecticide molecules. They are also involved in insecticide detoxification by mediating O-dealkylation and catalyzing dehydrochlorination (Chen et al 2018;Konanz and Nauen 2004;Kostaropoulos et al 2001;Lyall 2006;Vontas et al 2001). The GST activity has been associated with resistance to pesticides in many insects.…”