Antimicrobial activity of proteins secreted by Xanthomonas citri against microorganisms of medical interest

Abstract

Xanthomonas citri (XAC) is a phytopathogen that infects citrus trees, causing citrus canker. This bacterium possesses a secretion system that takes part in the competition for the environment, the Type IV Secretion System (T4SS), which is transmembrane machinery that contains an injection pilus responsible for the delivery of the secreted proteins into other microorganisms. One of these proteins, XAC2609, has been described and shown lysozyme-like activity in vitro assays against bacteria. There are other 12 putative effectors in the system, with domains that range from lipase to lysozyme-like and whose structures and functions have not been described yet. Therefore, in this project we aim to define the best methods for expression and purification of two other proteins secreted by the T4SS, XAC2885 and XAC3634, while also establishing protocols for testing the antibacterial activity of three XAC effectors, XAC2609, XAC2885 and XAC3634, and evaluate their effectiveness against microorganisms of clinical interest.