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Ettinger CL, Byrne FJ, de Souza Pacheco I, Brown DJ, Walling LL, Atkinson PW, Redak RA, Stajich JE. Transcriptome and population structure of glassy-winged sharpshooters (Homalodisca vitripennis) with varying insecticide resistance in southern California. BMC Genomics 2022; 23:721. [PMID: 36273137 PMCID: PMC9587601 DOI: 10.1186/s12864-022-08939-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 10/13/2022] [Indexed: 12/02/2022] Open
Abstract
Background Homalodisca vitripennis Germar, the glassy-winged sharpshooter, is an invasive insect in California and a critical threat to agriculture through its transmission of the plant pathogen, Xylella fastidiosa. Quarantine, broad-spectrum insecticides, and biological control have been used for population management of H. vitripennis since its invasion and subsequent proliferation throughout California. Recently wide-spread neonicotinoid resistance has been detected in populations of H. vitripennis in the southern portions of California’s Central Valley. In order to better understand potential mechanisms of H. vitripennis neonicotinoid resistance, we performed RNA sequencing on wild-caught insecticide-resistant and relatively susceptible sharpshooters to profile their transcriptome and population structure. Results We identified 81 differentially expressed genes with higher expression in resistant individuals. The significant largest differentially expressed candidate gene linked to resistance status was a cytochrome P450 gene with similarity to CYP6A9. Furthermore, we observed an over-enrichment of GO terms representing functions supportive of roles in resistance mechanisms (cytochrome P450s, M13 peptidases, and cuticle structural proteins). Finally, we saw no evidence of broad-scale population structure, perhaps due to H. vitripennis' relatively recent introduction to California or due to the relatively small geographic scale investigated here. Conclusions In this work, we characterized the transcriptome of insecticide-resistant and susceptible H. vitripennis and identified candidate genes that may be involved in resistance mechanisms for this species. Future work should seek to build on the transcriptome profiling performed here to confirm the role of the identified genes, particularly the cytochrome P450, in resistance in H. vitripennis. We hope this work helps aid future population management strategies for this and other species with growing insecticide resistance. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08939-1.
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Affiliation(s)
- Cassandra L Ettinger
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, USA.
| | - Frank J Byrne
- Department of Entomology, University of California, Riverside, Riverside, CA, USA
| | | | - Dylan J Brown
- Department of Entomology, University of California, Riverside, Riverside, CA, USA
| | - Linda L Walling
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, USA.,Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, USA
| | - Peter W Atkinson
- Department of Entomology, University of California, Riverside, Riverside, CA, USA.,Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, USA
| | - Richard A Redak
- Department of Entomology, University of California, Riverside, Riverside, CA, USA
| | - Jason E Stajich
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, CA, USA. .,Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, USA.
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Zhang L, Zhang J, Wang C, He Y, Wen X, Xu Z, Wang C. Toxicological, Behavioral, and Horizontal Transfer Effects of Cycloxaprid Against Formosan Subterranean Termites (Blattodea: Rhinotermitidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2022; 115:1240-1250. [PMID: 35583241 DOI: 10.1093/jee/toac073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Indexed: 06/15/2023]
Abstract
Cycloxaprid, 9-((6-chloropyrid-3-yl)methyl)-4-nitro-8-oxa-10,11-dihydroimidazo-[2,3-a]-bicyclo-[3,2,1]-oct-3-ene, is a cis-configuration neonicotinoid insecticide. In the present study, the lethal and sublethal effect of cycloxaprid against Formosan subterranean termites, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), was evaluated and compared with fipronil. Toxicity bioassays showed that cycloxaprid had slightly lower toxicity than fipronil. The minimum cycloxaprid concentration in sand and soil that causes 100% termite mortality was 100 ppm. Similar to fipronil, cycloxaprid significantly reduced wood consumption and tunneling activities of termites. In the tunneling-choice tests, termite tunneling activity measured in both length and area was significantly lower in sand treated with cycloxaprid (10 or 100 ppm) than that in untreated sand. In the aggregation-choice tests, cycloxaprid exhibited inhibition to termite aggregation starting from 100 ppm. In addition, cycloxaprid exhibited significant horizontal transfer effect at 10 ppm. In conclusion, our study showed that cycloxaprid is slightly less toxic than fipronil and more repellent to C. formosanus than fipronil. Future studies are needed to evaluate the effectiveness of cycloxaprid against subterranean termites in the field.
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Affiliation(s)
- Lang Zhang
- Guangdong Key Laboratory for Innovation Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Jianlong Zhang
- Guangdong Key Laboratory for Innovation Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Changlu Wang
- Department of Entomology, Rutgers University, New Brunswick, NJ 08901, USA
| | - Yinghao He
- Guangdong Key Laboratory for Innovation Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Xiujun Wen
- Guangdong Key Laboratory for Innovation Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Zhiping Xu
- Shanghai Key Laboratory of Biological Chemistry, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Cai Wang
- Guangdong Key Laboratory for Innovation Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
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Cheng X, Zhang H, Wang Y, Zhang S, Ye Q. Fate of the neonicotinoid insecticide cycloxaprid in different soils under oxic conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 821:153448. [PMID: 35093364 DOI: 10.1016/j.scitotenv.2022.153448] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/17/2022] [Accepted: 01/22/2022] [Indexed: 06/14/2023]
Abstract
Neonicotinoids are the most widely used pesticides worldwide due to their high toxicity to invertebrates. However, these compounds also increase the probability of environmental contamination. Cycloxaprid (CYC) is a promising neonicotinoid due to its insecticidal effectiveness and low cross resistance, but little is known about its fate in soils. Using radioisotope tracing techniques, the fate of 14C-labeled CYC enantiomers and racemic mixtures in aerobic soil was investigated in this research. After 100 d of incubation, the extractable residue (ER) of CYC decreased from 89.6% to 36.4% in red clay soil, from 46.1% to 10.1% in yellow loam soil, and from 93.2% to 12.2% in coastal saline soil. The radioactivity was substantially lower in methanol than in the other two solvents, but the distribution of CYC ER in various solvents across the three soils dramatically differed. The fraction of radioactive CYC that diffused into bound residue (BR) in the three soils increased over time to 56.8-83.0%. The variability in BR was influenced by soil properties such as organic matter concentration, pH, and residual microbial activity. Among the soils, yellow loam soil had the greatest tendency (53.0-83.0%) to form BR, while red clay soil showed the lowest capacity (7.5-61.2%). Cumulative mineralization (MI) to 14CO2 accounted for 0.12-0.23%, 6.69-7.31% and 14.82-20.06% in acidic soil, neutral soil and alkaline soil, respectively, which suggests that the environmental fate of chiral pesticides may be influenced by soil pH. No stereoselective behavior was detected in this study. These findings provide a framework to assess the environmental impact and ecological safety of CYC application.
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Affiliation(s)
- Xi Cheng
- Institute of Nuclear Agricultural Sciences, Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture of the PRC and Zhejiang Province, Zhejiang University, Hangzhou 310058, PR China.
| | - Hanxue Zhang
- Shanghai Qizhen Environmental Technology Co., Ltd, 659 Maoyuan Rd, Shanghai 201403, PR China
| | - Yichen Wang
- Hangzhou Botanical Garden, Hangzhou 310013, PR China.
| | - Sufen Zhang
- Institute of Nuclear Agricultural Sciences, Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture of the PRC and Zhejiang Province, Zhejiang University, Hangzhou 310058, PR China.
| | - Qingfu Ye
- Institute of Nuclear Agricultural Sciences, Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture of the PRC and Zhejiang Province, Zhejiang University, Hangzhou 310058, PR China.
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