Abstract
Nicotinamide adenine dinucleotide phosphate (NADPH)-cytochrome P450 reductases (CPRs) function as redox partners of cytochrome P450 monooxygenases (P450s). CPRs and P450s in insects have been found to participate in insecticide resistance. However, the CPR of the moth Spodoptera litura has not been well characterized yet. Based on previously obtained transcriptome information, a full-length CPR cDNA of S. litura (SlCPR) was PCR-cloned. The deduced amino acid sequence contains domains and residues predicted to be essential for CPR function. Phylogenetic analysis with insect CPR amino acid sequences showed that SlCPR is closely related to CPRs of Lepidoptera. Quantitative reverse transcriptase PCR (RT-qPCR) was used to determine expression levels of SlCPR in different developmental stages and tissues of S. litura. SlCPR expression was strongest at the sixth-instar larvae stage and fifth-instar larvae showed highest expression in the midgut. Expression of SlCPR in the midgut and fat body was strongly upregulated when fifth-instar larvae were exposed to phoxim at LC15 (4 μg/mL) and LC50 (20 μg/mL) doses. RNA interference (RNAi) mediated silencing of SlCPR increased larval mortality by 34.6% (LC15 dose) and 53.5% (LC50 dose). Our results provide key information on the SlCPR gene and indicate that SlCPR expression levels in S. litura larvae influence their susceptibility to phoxim and possibly other insecticides.
Highlights
The tobacco cutworm, Spodoptera litura (F.) (Lepidoptera, Noctuidae) is a serious polyphagous insect pest
According to Cheng et al (2017) [13] and nucleotide sequences deposited at the DDBJ/ENA/GenBank databases, S. litura possesses a single copy of the cytochrome P450 monooxygenases (P450s) reductases (CPRs) gene
Insect CPRs in phylogenetic trees are clearly segregated into clusters that correspond to different insect orders [16,21]
Summary
The tobacco cutworm, Spodoptera litura (F.) (Lepidoptera, Noctuidae) is a serious polyphagous insect pest. The moth has a broad host range that includes economically important crops such as tomato, cotton, and groundnut [1]. Many field populations of S. litura acquired resistance to various insecticides, in Pakistan, China, and India. The task of controlling insecticide-resistant S. litura populations is becoming exceedingly challenging [1,2,3]. Phoxim has become one of the most widely used organophosphate insecticides for the control of S. litura [1,2,3]. Cytochrome P450 monooxygenases (CYPs or P450s) belong to a superfamily of heme-containing enzymes that catalyze the monooxygenation of xenobiotics and endogenous compounds [4,5].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
