Interaction studies between the bacterium Candidatus Liberibacter asiaticus and the insect vector Diaphorina citri, associated with HLB in Citrus

Abstract

Citrus cultivation is of great importance to the world economy. Important producers are found in Brazil and the United States, with production concentrated mainly in the "Citrus Belt" and the state of Florida, respectively. However, significant productivity losses are linked to various diseases that affect the genus. Among these diseases, Huanglongbing (HLB) stands out as the most serious disease in citrus growing, with no effective control to date. The agents associated with HLB, Candidatus Liberibacter asiaticus (CLas) and the vector Diaphorina citri are significantly widespread in citrus regions, causing damage to citriculture worldwide. The definition of complex protein networks is essential for improving the understanding of biological processes. Thus, studying the HLB vector-bacteria interaction can provide important insights into the disease, as well as determining specific targets for its management. Thus, this work aims to understand the relationship between D. citri and CLas, and proteins involved in the process of HLB transmission by the psyllid, with a focus on the cysteine peptidases DCcathB and DcCathL, and inhibitors of cysteine peptidases (citrus cystatins) and flagellins that will be used to investigate bacterium-vector interactions, which seems to be a promising strategy to slow down the spread of HLB disease. Thus, this project aims to employ methods such as Yeast two-hybrid (Y2H), immunolocalization, Bimolecular Fluorescence Complementation (BiFC), microscopy, artificial diet assays, in order to obtain greater elucidation of the spread of HLB and the biological processes involved in the plant-bacteria-vector interaction, thus enabling appropriate management for the most serious disease of Citrus.