Genome‐wide assessment and development of molecular diagnostic methods for imidacloprid‐resistance in the brown planthopper, Nilaparvata lugens (Hemiptera; Delphacidae)

Abstract

BACKGROUND The brown planthopper, Nilaparvata lugens (Stål), is one of the most notorious pests of rice throughout Asia. The brown planthopper has developed high resistance to imidacloprid, a member of neonicotinoid insecticides. Several genes and mutations conferring imidacloprid resistance in N. lugens, especially in eastern and southeastern Asia populations, have been reported. Thus, the key mechanisms of imidacloprid resistance need to be examined. RESULTS RNA‐seq analyses revealed that only one cytochrome P450 monooxygenase gene, CYP6ER1, was commonly upregulated in the five resistant strains tested. Sequences of CYP6ER1, which were highly expressed in the imidacloprid‐resistant strains, contained a three‐nucleotide deletion in the coding region, and amino acid substitutions and deletion, compared to that in an imidacloprid‐susceptible strain. RNAi‐mediated gene knockdown of CYP6ER1 increased imidacloprid susceptibility in a resistant strain. Further, we established two simple and convenient PCR‐based molecular diagnostic methods to detect the CYP6ER1 locus with the three‐nucleotide deletion. Using these methods, the resistance of F2 progenies derived from the crosses of F1 siblings from susceptible and resistant parents was analyzed, showing that the imidacloprid resistance had a relationship to the CYP6ER1 locus with the three‐nucleotide deletion. CONCLUSION The overexpression of a variant CYP6ER1 with amino acid substitutions and deletion was involved in imidacloprid resistance in N. lugens. Based on these findings, molecular diagnostic methods have been developed and are promising tools for monitoring imidacloprid resistance in paddy fields. © 2020 Society of Chemical Industry

Molecular Evolutionary Mechanisms of CYP6ER1vA-Type Variant Associated with Resistance to Neonicotinoid Insecticides in Field Populations of Nilaparvata lugens

“…In contrast to the results for the two susceptible strains, NLS (collected in 1984 in Japan) and Izumo-87 (collected in 1987 in Japan), which only expressed the ancestral CYP6ER1vL -type gene in their genomes, our S strain (collected in 1995 in China) has already undergone the T318S, A375del, and A376G mutations, all of which are key mutations that distinguish CYP6ER1vA -type from CYP6ER1vL and other variants ( vL and other variants without these key mutations are totally defined as vL -type in the current study). Utilizing S-A and S-B strains with specific CYP6ER1 genotypes isolated from S strain and multiple field strains provided unambiguous and compelling evidence to suggest that the expression level of CYP6ER1vA -type is associated with the resistance of N.…”

“…lugens and then examined the genotypes of their offspring. If the heterogeneity was an allelic variant on a pair of chromosomes, the genotypes of the offspring produced from the vA-type/vL-type-hetero parents would be expected to segregate into vL-type-homo, vA-type/vL-type-hetero, and vA-type-homo with a 1:2:1 ratio . However, during three trials conducted for the S-B or XA-2017 strains, only vA-type/vL-type-hetero, genotype was observed in the offspring, with no vA-type-homo or vL-type-homo genotypes detected (Table S5).…”

Transcriptomic modulation in response to an intoxication with deltamethrin in a population of Triatoma infestans with low resistance to pyrethroids

“…In this sense, high-throughput RNA-Seq represents an approach to identify expression changes that could be involved in detoxification mechanisms, e.g. comparing transcription profiles of susceptible and resistant populations (as for example in [18][19][20]). Recently, the analysis of transcriptomic databases allowed the identification of new relevant components of the detoxifying response to insecticides in mosquitoes [21][22][23].…”

The Role of Insect Cytochrome P450s in Mediating Insecticide Resistance

“…In addition, the polymorphism analysis of CYP6Z1 and CYP6Z3 showed 19 amino acid changes in CYP6Z1 and 9 amino acid changes in CYP6Z3, which identified potential mutations related to pyrethroid resistance in Anopheles [109]. It has recently been discovered that the overexpression of a variant CYP6ER1 with amino acid substitutions and deletions in N. lugens populations in East and Southeast Asia is associated with imidacloprid resistance [110].…”