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Tavares CS, Mishra R, Kishk A, Wang X, Ghobrial PN, Killiny N, Bonning BC. The beta pore-forming bacterial pesticidal protein Tpp78Aa1 is toxic to the Asian citrus psyllid vector of the citrus greening bacterium. J Invertebr Pathol 2024; 204:108122. [PMID: 38710321 DOI: 10.1016/j.jip.2024.108122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 04/22/2024] [Accepted: 05/02/2024] [Indexed: 05/08/2024]
Abstract
The Asian citrus psyllid (ACP) Diaphorina citri transmits the causative agent of huanglongbing, or citrus greening disease, that has decimated global citrus production. Pesticidal proteins derived from bacteria such as Bacillus thuringiensis (Bt) can provide effective and environmentally friendly alternatives for management of D. citri, but few with sufficient toxicity to D. citri have been identified. Here, we report on the toxicity of 14 Bt-derived pesticidal proteins from five different structural groups against D. citri. These proteins were selected based on previously reported toxicity to other hemipteran species and on pesticidal protein availability. Most of the proteins were expressed in Escherichia coli and purified from inclusion bodies or His-tag affinity purification, while App6Aa2 was expressed in Bt and purified from spore/crystal mixtures. Pesticidal proteins were initially screened by feeding psyllids on a single dose, and lethal concentration (LC50) then determined for proteins with significantly greater mortality than the buffer control. The impact of CLas infection of D. citri on toxicity was assessed for selected proteins via topical feeding. The Bt protein Tpp78Aa1 was toxic to D. citri adults with an LC50 of approximately 204 µg/mL. Nymphs were more susceptible to Tpp78Aa1 than adults but no significant difference in susceptibility was observed between healthy and CLas-infected nymphs or adults. Tpp78Aa1 and other reported D. citri-active proteins may provide valuable tools for suppression of D. citri populations.
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Affiliation(s)
- Clebson S Tavares
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA.
| | - Ruchir Mishra
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA
| | - Abdelaziz Kishk
- Department of Plant Pathology, Citrus Research and Education Center, IFAS, University of Florida, Lake Alfred, FL 33850, USA; Department of Plant Protection, Faculty of Agriculture, Tanta University 31527, Egypt
| | - Xinyue Wang
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA
| | - Pierre N Ghobrial
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA
| | - Nabil Killiny
- Department of Plant Protection, Faculty of Agriculture, Tanta University 31527, Egypt
| | - Bryony C Bonning
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, USA
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Ibanez F, Vieira Rocha S, Dawson WO, El-Mohtar C, Robertson C, Stelinski LL, Soares-Costa A. Gene silencing of cathepsins B and L using CTV-based, plant-mediated RNAi interferes with ovarial development in Asian citrus psyllid (ACP), Diaphorina citri. FRONTIERS IN PLANT SCIENCE 2023; 14:1219319. [PMID: 37841623 PMCID: PMC10570424 DOI: 10.3389/fpls.2023.1219319] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 09/12/2023] [Indexed: 10/17/2023]
Abstract
Diaphorina citri Kuwayama (Hemiptera: Liviidae) is a vector of the bacteria Candidatus Liberibacter americanus (CLam) and Candidatus Liberibacter asiaticus (CLas), which are phloem-restricted and associated with the most important and destructive worldwide citrus disease, Huanglongbing (HLB). Currently, no cure for HLB has been described. Therefore, measures have focused on reducing D. citri populations. In these insects, cathepsin B (DCcathB) and L (DCcathL) enzymes play an important role in digestion, and are involved in embryogenesis, immune defense, and ecdysis. In this study, we used a CTV-based vector to deliver dsRNA (CTV-dsRNA) into Citrus macrophylla plants targeting DCcathB and DCcathL genes in D. citri that fed on the phloem of these CTV-RNAi infected plants. Subsequently, we evaluated expression of DCcathB and DCcathL genes as well as the Vitellogenin (Vg) gene by RT-qPCR in D. citri fed on CTV-dsRNA occurring in plant phloem. It was found that a defective phenotype in D. citri females as a result of knockdown of DCcathB and DCcathL genes mediated by CTV dsRNA. These results showed that Psyllids fed on plants treated with the CTV-dsRNA exhibited downregulation of the Vg gene, one of the most important genes associated with embryogenic and female development, which was associated with dsRNA-mediated silencing of the two cathepsin genes. Based on our findings, a CTV-based strategy for delivering RNAi via plants that targets DCcathB and DCcathL genes may represent a suitable avenue for development of dsRNA-based tools to manage D. citri that limits the spread of HLB.
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Affiliation(s)
- Freddy Ibanez
- Department of Entomology, Texas A&M AgriLife Research, Weslaco, TX, ;United States
| | - Sâmara Vieira Rocha
- Department of Genetics and Evolution, Federal University of São Carlos, São Carlos, SP, ;Brazil
| | - William O. Dawson
- Plant Pathology Department, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, ;United States
| | - Choaa El-Mohtar
- Plant Pathology Department, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, ;United States
| | - Cecile Robertson
- Plant Pathology Department, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, ;United States
| | - Lukasz L. Stelinski
- Department of Entomology and Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, ;United States
| | - Andrea Soares-Costa
- Plant Pathology Department, Citrus Research and Education Center, University of Florida, Lake Alfred, FL, ;United States
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Santos Correa KC, Moreira AC, Abd El-Raheem Ibrahim AG, Ramos de Jesus HC, Micocci KC, Crizóstomo Kock FV, Bueno OC, Venâncio T, Henrique-Silva F, Souza DHF. Identification and characterization of a recombinant cysteine peptidase (AsCathL) from leaf-cutting ant Atta sexdens Linnaeus, 1758 (Hymenoptera, Formicidae). Protein Expr Purif 2023; 201:106174. [DOI: 10.1016/j.pep.2022.106174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/10/2022] [Accepted: 09/14/2022] [Indexed: 11/24/2022]
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