Identification of interaction partner proteins of XanB, an enzyme essential for the pathogenicity of Xanthomonas citri subsp. citri

• Grant number: 24/21337-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2025
• End date: December 31, 2025
• Field of knowledge: Biological Sciences - Biochemistry - Biochemistry of Microorganisms
• Principal Investigator: Maria Teresa Marques Novo Mansur
• Grantee: Ana Elisa Moraes Rosa
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Citrus canker is an important phytopathology that affects citriculture worldwide, generating significant impacts on citrus fruit production, especially in Brazil, one of the five largest citrus producers in the world. Among the proteins involved in the pathogenicity of the bacterium that causes the disease, Xanthomonas citri subsp. citri (XAC), is the XanB protein, a bifunctional enzyme associated with xanthan gum biosynthesis and biofilm formation. This protein was detected in greater quantities on the surface of XAC in infectious situations (in vivo) than in non-infectious situations (in vitro) in previous work at LBBMA-UFSCar. This project aims to investigate the protein-protein interactions of recombinant XanB (rXanB) in vitro to identify partner proteins associated with XAC pathogenicity. The rXanB protein will be obtained by heterologous expression in Escherichia coli and used for the Pull-down assay, through which its interaction with proteins from cell lysate and periplasm-enriched fractions of XAC cells (wild-type) and a XAC mutant with XanB deletion, grown in pathogenicity-inducing medium in vitro, will be evaluated. The interaction profiles will be analyzed by SDS-PAGE and the partner proteins will be identified by mass spectrometry. From this we hope to identify interactions that provide insights into the XanB protein, such as targeting mechanisms in XAC, which should differ from those conventionally known, since XanB does not have a predicted signal peptide. We also hope to broaden our understanding of the molecular processes associated with the pathogenicity of XAC, contributing to the development of more sustainable control strategies in relation to the copper compounds currently used, which pose risks to the environment and human health.