The expression and function of opsin genes related to the phototactic behavior of Asian citrus psyllid

Liu

Pest Management Science

et al. 2021

BACKGROUND: Opsins are crucial for animal vision. The identity and function of opsins in Plutella xylostella remain unknown. The aim of the research is to confirm which opsin gene(s) contribute to phototaxis of P. xylostella.RESULTS: LW-opsin, BL-opsin and UV-opsin, were identified in the P. xylostella genome. LW-opsin was more highly expressed than the other two opsin genes, and all three genes were specifically expressed in the head. Three P. xylostella strains, LW-13 with a 13-bp deletion in LW-opsin, BL + 2 with a 2-bp insertion in BL-opsin, and UV-29 with a 5-bp insertion and a 34-bp deletion in UV-opsin, were established from the strain G88 using the CRISPR/Cas9 system. Among the three opsin-knockout strains, only male and female LW-13 exhibited weaker phototaxis to lights of different wavelengths and white light than G88 at 2.5 lx due to defective locomotion, and LW-13 was defective to sense white, green and infrared lights. The locomotion of LW-13 was reduced compared with G88 at 2.5, 10, 20, 60, 80, 100, and 200 lx under the green light, but the locomotion of LW-13 female was recovered at 80, 100 and 200 lx. The defective phototaxis to the green light of male LW-13 was not affected by light intensity, while the defective phototaxis to the green light of female LW-13 was recovered at 10, 20, 60, 80, 100, and 200 lx. CONCLUSION: LW-opsin is involved in light sensing and locomotion of P. xylostella, providing a potential target gene for controlling the pest.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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CRISPR/Cas9‐mediated knockout of LW‐opsin reduces the efficiency of phototaxis in the diamondback moth Plutella xylostella

Liu

Pest Management Science

et al. 2021

“…Artificial diet 200-1000 ng µL − 1 Higher mortality (Galdeano et al 2017) The fertility gene boule (DcBol) Artificial diet 50-500 ng µL − 1 Higher mortality (Yu and Killiny 2018b) Sucrose hydrolase (DcSuh) Topical feeding 50-500 ng µL − 1 Higher mortality due do hyperosmotic pressure (Santos-Ortega and Killiny 2018) Cytochrome P450 (CYP4g15, CYP303A1, CYP4C62 and CYP6BD5), glutathione S-transferase gene (GSTS1) and esterase gene (EST-6) Topical feeding 10-100 ng µL − 1 Increased susceptibility to insecticides and increased adult mortality (Tian et al 2019a) UDP-glycosyltransferases (UGTs) Topical feeding 100 and 200 ng µL − 1 Increased susceptibility to imidacloprid and increased adult mortality (Tian et al 2019b) Chitin synthase (DcCHS) Artificial diet 150 ng µL − 1 High mortality and malformed phenotypes (Lu et al 2019a Tropomyosin1-X2 isoform (DcTm1-X2) artificial diet 150 ng µL − 1 High mortality and increased CLas infection (Lu et al 2019b) Opsin genes (Dc-UV, Dc-LW and Dc-BW) Topical application 1000 ng µL − 1 Reduced phototactic efficiency to ultraviolet light, green light, and blue light (Li et al 2020) Chitin deacetylase 3 (DcCDA3) Artificial diet 300 ng µL − 1 No obvious influence on D. citri phenotype (Yu et al 2020) • delivery methods included topical application (dsRNA applied to psyllid abdomen then it penetrates to haemocoel), topical feeding (dsRNA applied to the mouthparts and it is acquired though feeding), artificial diet (dsRNA added to 20% sucrose solution between two layers of parafilm and insects acquire it through feeding) and virus-based plant mediated (virus induced gene silencing and insect acquire dsRNA through feeding on plants)…”

Section: Challenges and Prospectsmentioning

confidence: 99%

RNA interference-mediated control of Asian citrus psyllid, the vector of the huanglongbing bacterial pathogen

Killiny

2020

Trop. plant pathol.

Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is the natural vector of the Huanglongbing (HLB) pathogen that presents an unparalleled challenge to citrus production. RNA interference (RNAi) has already shown great potential for insect pest management owing to its high specificity. RNAi technique relies on the delivery of exogenous double-stranded RNAs (dsRNAs) that target essential genes in insects. The D. citri genome possesses three dsRNase homologs and all core RNAi machinery genes, aside from the R2D2 that functions as a cofactor of Dicer-2 in the siRNA pathway. Nevertheless, ever-increasing research on the application of RNAi to suppress D. citri population has promulgated outstanding progress. Here, we provide a comprehensive review of the recent literature, and summarize the current understanding of RNAi mechanisms and advances in the applications of RNAi in D. citri. The major challenges including the potential of dsRNA degradation, target gene selection, and dsRNA delivery methods, as well as the implications of using RNAi for D. citri control are reviewed.

“…Opsins covalently bind to small molecular chromophores to form light-sensitive photopigments—rhodopsins—which initiate the phototransduction cascade [ 2 , 4 ]. Opsins contribute to phototactic behaviors in insects, such as Drosophila [ 13 ], Nephotettix cincticeps (Uhler, 1896) (rice green leafhopper, Hemiptera: Cicadellidae) [ 14 ], Spodoptera exigua (Hübner, 1808) (beet armyworm, Lepidoptera: Noctuidae) [ 15 ], Diaphorina citri (Kuwayama, 1908) (Asian citrus psyllid, Hemiptera: Liviidae) [ 16 ], and Plutella xylostella (Linnaeus, 1758) (diamondback moth, Lepidoptera: Plutellidae) [ 17 ]. These studies, however, only focus on the function of opsin, and research is lacking on changes in the expression levels of other genes in the phototransduction pathway caused by an opsin mutation.…”

Section: Introductionmentioning

confidence: 99%

An LW-Opsin Mutation Changes the Gene Expression of the Phototransduction Pathway: A Cryptochrome1 Mutation Enhances the Phototaxis of Male Plutella xylostella (Lepidoptera: Plutellidae)

Lin

Qiu

et al. 2023

Insects

Plutella xylostella is a typical phototactic pest. LW-opsin contributes to the phototaxis of P. xylostella, but the expression changes of other genes in the phototransduction pathway caused by the mutation of LW-opsin remain unknown. In the study, the head transcriptomes of male G88 and LW-opsin mutants were compared. A GO-function annotation showed that DEGs mainly belonged to the categories of molecular functions, biological processes, and cell composition. Additionally, a KEGG-pathway analysis suggested that DEGs were significantly enriched in some classical pathways, such as the phototransduction-fly and vitamin digestion and absorption pathways. The mRNA expressions of genes in the phototransduction-fly pathway, such as Gq, ninaC, and rdgC were significantly up-regulated, and trp, trpl, inaD, cry1, ninaA and arr1 were significantly down-regulated. The expression trends of nine DEGs in the phototransduction pathway confirmed by a RT-qPCR were consistent with transcriptomic data. In addition, the influence of a cry1 mutation on the phototaxis of P. xylostella was examined, and the results showed that the male cry1 mutant exhibited higher phototactic rates to UV and blue lights than the male G88. Our results indicated that the LW-opsin mutation changed the expression of genes in the phototransduction pathway, and the mutation of cry1 enhanced the phototaxis of a P. xylostella male, providing a basis for further investigation on the phototransduction pathway in P. xylostella.