Characterization of the phoP gene (XAC4023) from Xanthomonas citri subsp. citri and its relationship with cell division

• Grant number: 20/02340-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): January 01, 2021
• Effective date (End): December 31, 2021
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: Henrique Ferreira
• Grantee: Hayen Alonso
• Host Institution: Instituto de Biociências (IB). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil

Abstract

According to IBGE data, the state of São Paulo is the world's largest producer of sweet oranges, with most of the production destined for the manufacture of juice. Citrus cancer is one of the most worrying bacterial diseases for citrus in Brazil. The most widespread and severe form of cancer, citrus cancer type A, is caused by the bacterium Xanthomonas citri subsp. citri (X. citri). The characterization of genes not yet or little studied in X. citri is important for the evaluation of the potential of new compounds to control citrus canker. The two-component system (TCS) PhoP-PhoQ, represents a typical signal transduction system. PhoQ is a histidine kinase (HK) attached to the inner membrane. After detecting environmental signals, PhoQ activates the transfer of a phosphate group to PhoP, a cytosolic response regulator (RR), which has the function of activating or inhibiting the transcription of genes. The PhoP-PhoQ TCS regulates the virulence of numerous pathogenic bacteria, especially those belonging to the Proteobacteria taxon. Preliminary experiments by our research group showed that the deletion of the phop gene in X. citri 306 caused cell filamentation, suggesting that this gene may be directly or indirectly related to processes of cell division and / or chromosomal segregation. Thus, one of the objectives of this work is to study the subcellular location of the GFP-Zap a protein in the mutant strain opphop and thus verify whether the formation of the Z-ring is anomalous. In addition, it is intended to perform a phoP complementation, in order to verify its direct role in the altered phenotype. Finally, we will evaluate the cell morphology of the mutant, the distribution of the nucleoids (DAPI staining), growth profile in culture, mobility, biofilm formation, pathogenicity and compare with the profiles observed in these questions for the wild isolate.