Identification, recombinant production and characterization of cysteine peptidases from the insect Diaphorina citri, vector of the Citrus Disease Huanglongbing

• Grant number: 19/09652-7
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Effective date (Start): August 01, 2019
• Effective date (End): November 30, 2023
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Adriana Karaoglanovic Carmona
• Grantee: Patricia da Silva Lima
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

Huanglongbing (HLB) is one of the major diseases of citrus, which is caused by the Gram-negative bacteria of the genus Candidatus Liberibacter The main symptoms of HLB in plants are the yellowing of the branches, chlorosis of the leaves and damages to the fruits, which become asymmetric, small, with aborted seeds and bitter taste. In Asia and the Americas, the spread of the disease occurs through transmission of the pathogen through the psyllid vector Diaphorina citri Kuwayama, being prevention the best mode of control. The combat against D. citri is done with insecticides, normally harmful to the environment and human health, and for this reason, forms of biological control and the use of biotechnology are welcome. The search for molecular targets is interesting, and cathepsins are promising enzymes because they have a variety of actions in living beings. In insects, cathepsins of the class of cysteine peptidases, besides being digestive enzymes act on metamorphosis, activation of apoptosis, immune system, among others. The characterization of these enzymes in D. citri, and the search for their inhibitors, may lead, in the future, to the production of transgenic plants overexpressing inhibitors capable of delaying the development and proliferation of the insect. In addition, gene silencing techniques of these enzymes may be developed. In the present project we propose the identification, recombinant production in E. coli and characterization of Diaphorina citri cathepsins (L-like and B-like), as well as enzymatic inhibition assays using synthetic inhibitors and citrus cystatins, aiming the validation of these enzymes as possible targets for insect control. (AU)