ORIGINAL RESEARCH article
Front. Insect Sci.
Sec. Pest Management
This article is part of the Research TopicNew Integrated Pest Management: Emerging OpportunitiesView all 5 articles
Recombinant Cystatin Ingestion by Diaphorina citri Reduces Insect Survival: Insights into the HLB host–bacteria interaction (D. citri–CLas) focused on DcCathL studies
Provisionally accepted
Sâmara Vieira Rocha1*
Chiara Bernardini2Poulami Sarkar3Chun-Yi Lin4
Karina Fan1
João Paulo Rodrigues Marques5
Juan Camilo Cifuentes-Arenas6
Maria-Cristina da Silva Pranchevicius1
Nelson Arno Wulff6Fabrício J. Jaciani6
Marcelo De Bello Cioffi1
Daniel Stanton4
Amit Levy4
Andrea Soares-Costa1*- 1Universidade Federal de Sao Carlos Centro de Ciencias Biologicas e da Saude, São Carlos, Brazil
- 2Universita degli Studi di Udine, Udine, Italy
- 3University of California Riverside, Riverside, United States
- 4University of Florida, Lake Alfred, United States
- 5Universidade de Sao Paulo, Pirassununga, Brazil
- 6Fundo de Defesa da Citricultura, Araraquara, Brazil
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Huanglongbing (HLB) is considered the most serious Citrus disease for which there are currently no effective control methods. The putative agents of HLB, Candidatus Liberibacter asiaticus (CLas), and the vector Diaphorina citri, are widespread in citrus regions, causing losses in citrus cultivation worldwide. Studying the interactions between D. citri and CLas can elucidate disease epidemiology and determine specific targets for HLB control. This work aimed to improve our understanding of the host–bacteria (D. citri–CLas) relationship, focusing on cysteine peptidase (DcCathL) and its inhibition by citrus cystatin (CsinCPI-2). Using immunolocalization techniques, we demonstrated the presence of DcCathL in midgut, ovary and salivary gland tissues. qPCR and FISH revealed upregulation of the DcCathL gene in CLas bacterium-infected insects. The use of cathepsin inhibitors, called cystatins, in artificial feeding assays revealed that cystatin ingestion increased psyllid mortality in CLas-free and CLas-infected adults and in the CLas-free group of D. citri nymphs. The development of inhibitors that can disrupt the interactions between bacteria and vectors by blocking DcCathL activity may represent a promising strategy to prevent the spread of HLB disease.
Keywords: Huanglongbing, HLB, Diaphorina citri, Candidatus Liberibacter asiaticus, CLAS, Cystatins, Cathepsins
Received: 05 Sep 2025; Accepted: 23 Jan 2026.
Copyright: © 2026 Rocha, Bernardini, Sarkar, Lin, Fan, Marques, Cifuentes-Arenas, Pranchevicius, Wulff, Jaciani, Cioffi, Stanton, Levy and Soares-Costa. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Sâmara Vieira Rocha
Andrea Soares-Costa
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