Baseline determination, susceptibility monitoring and risk assessment to triflumezopyrim in Nilaparvata lugens (Stål)

BACKGROUND: Triflumezopyrim, a novel commercialized mesoionic chemical insecticide, has been confirmed as a promising insecticide for efficiently controlling the brown planthopper, Nilaparvata lugens (Stål). Here, a laboratory triflumezopyrimresistant (TR) strain and an isogenic susceptible (TS) strain were established to characterize the inheritance and fitness costs of triflumezopyrim resistance in N. lugens.RESULTS: After 29 generations of successive selection with triflumezopyrim, the TR strain developed a 155.23-fold higher resistance level than the TS strain. The median lethal concentration (LC 50 ) values from progenies (F 1 RS and F 1 SR) of reciprocal crosses between TR and TS strains suggested that triflumezopyrim resistance in N. lugens was autosomal and codominant. Chi-square analyses of self-bred and backcrossed progenies suggested that the resistance results from a polygenic effect. Compared to the TS strain, the TR strain showed a lower relative fitness (0.62) with a significantly decreased female adult period, longevity, total fecundity, egg hatchability, intrinsic rate of increase (r), finite rate of increase (⊗), net reproductive rate (R 0 ), and prolonged pre-adult period and total preoviposition period (TPOP).CONCLUSION: The inheritance mode of triflumezopyrim resistance in N. lugens was characterized as autosomal, codominant and polygenic. The resistance had a fitness cost, which may be an important factor limiting the evolution of resistance. These findings provide valuable information for optimizing resistance management strategies to delay triflumezopyrim resistance development and maintain sustainable control of N. lugens.

Section: Discussionmentioning

confidence: 68%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Resistance of Nilaparvata lugens (Hemiptera: Delphacidae) to triflumezopyrim: inheritance and fitness costs

Qin

Jin

et al. 2021

“…Zhang et al reported that the median lethal concentration (LC 50 ) of TFM is 0.15 mg L −1 (0.120-0.181) using seedling-dip or 0.064 mg L −1 (0.051-0.082) against the susceptible strain of N. lugens (third-instar nymph) using rice-stem drip. 78 Zhu et al also reported that the LC 50 of TFM is 0.22 mg L −1 (0.18-0.26) against the susceptible strain of N. lugens (newly emerged female adult) using rice-seedling dip. 22 Accordingly, we inferred that seed dressing with TFM effectively controls N. lugens populations, and this may be due to the interaction between the residue toxicity and a secondary metabolism product in plants grown from TFM-coated seed.…”

Section: Discussionmentioning

confidence: 99%

“…Zhang et al . reported that the median lethal concentration (LC 50 ) of TFM is 0.15 mg L −1 (0.120–0.181) using seedling‐dip or 0.064 mg L −1 (0.051–0.082) against the susceptible strain of N. lugens (third‐instar nymph) using rice‐stem drip 78 . Zhu et al .…”

Section: Discussionmentioning

confidence: 99%

Seed dressing with triflumezopyrim controls brown planthopper populations by inhibiting feeding behavior, fecundity and enhancing rice plant resistance

Zhang²,

Chen

et al. 2021

BACKGROUND Triflumezopyrim (TFM), a novel mesoionic insecticide, has high efficiency at a low dosage, and is mainly used to control hopper species. A previous study demonstrated that seed dressing with TFM effectively controlled rice planthopper populations in mechanically transplanted rice fields; however, mode of action for control was unclear. RESULTS The study shows that seed dressing with TFM resulted in elevated levels of oxalic acid, flavonoids, phenolic substances, callose and other compounds associated with Nilaparvata lugens resistance in rice plants, and low TFM residue content in rice plant stem and grain. Host choice behavioral experiments showed that N. lugens females prefer feeding on untreated rice plants. Electrical penetration graph (EPG) data showed that seed dressing with TFM at medium and high doses significantly prolonged the non‐probing period and inhibited phloem ingestion in N. lugens females. These changes led to a significant decrease in female secretion of honeydew, expression of genes encoding vitellogenin and juvenile hormone acid methyltransferase, body weight and longevity, and significantly influenced several physiological parameters resulting in impaired oocyte growth, fecundity and population. Field survey data showed that seed dressing with TFM was efficacious and relatively durable in protecting rice plants from infestation by planthoppers. CONCLUSION This study revealed that seed dressing with TFM enhances rice plant resistance to N. lugens by limiting phloem ingestion and increasing the N. lugens non‐probing period; this leads to reduced fecundity of females and lowers N. lugens numbers in the field. © 2021 Society of Chemical Industry

Overexpression of ATP‐binding cassette transporter Mdr49‐like confers resistance to imidacloprid in the field populations of brown planthopper, Nilaparvata lugens

Wang

Tao

Zhang

et al. 2021

BACKGROUND The brown planthopper (BPH), Nilaparvata lugens (Stål), is the most severe pest attacking rice crops using sucking mouthparts. It causes significant damages to rice growth and food production worldwide. With the long‐term and wide use of insecticides, field populations of BPH have developed resistance to many insecticides. RESULTS Here, we showed that upregulation of an ATP‐binding cassette transporter gene NlMdr49‐like contributes to imidacloprid resistance in field populations of BPH. A comparative transcriptome analysis was performed to evaluate the gene expression in two field populations (JXSG18 and YNTC18). Compared with a susceptible strain (Sus), 202 upregulated genes and 170 downregulated genes were identified in both field populations. Functional enrichment analysis revealed that the differentially expressed genes (DEGs) are mainly linked to metabolic process and transmembrane transport. Among the candidate DEGs, NlMdr49‐like was significantly upregulated in both field populations. Based on the genome and transcriptome of BPH, the full‐length complementary DNA of NlMdr49‐like was sequenced and its molecular characteristics were analyzed. Expression pattern analysis of various tissues showed that NlMdr49‐like was predominantly expressed in midgut and Malpighian tubules which are important excretion organs. Knocking down NlMdr49‐like reduced BPH resistance to imidacloprid, but did not affect its resistance to the other nine insecticides (chlorpyrifos, thiamethoxam, nitenpyram, dinotefuran, sulfoxaflor, triflumezopyrim, ethiprole, buprofezin and pymetrozine). Furthermore, a transgenic strain of Drosophila melanogaster overexpressing NlMdr49‐like was less susceptible to imidacloprid. CONCLUSIONS Our findings indicate that upregulation of NlMdr49‐like is another mechanism contributing to imidacloprid resistance in N. lugens. This result is helpful to further understand the resistance mechanism of N. lugens to imidacloprid. © 2021 Society of Chemical Industry.