Proteínas moonlighting e sua relação com a patogenicidade da bactéria Xanthomonas citri subsp. citri, causadora do cancro cítrico

Abstract

Citriculture has been present in Brazil since its colonization when orange seedlings were imported and commercialized. Due to the fertile soil and favorable climate, over the decades, Brazil has become the largest producer of oranges and exporter of orange juice worldwide, generating a lot of profit for the country. Nevertheless, over time, several diseases that bring significant losses to the citrus industry have also developed, and many of them still have no cure. Citrus canker is one of them and is caused by the bacterium Xanthomonas citri subsp. citri (Xac). Many investigations have been carried out to elucidate the infection mechanism of the bacteria in the host, how they defend themselves and why they are so virulent. After a proteomic analysis of the cell surface performed on Xac under two different conditions, host infection and non-infection, different amounts of some proteins on the surface were found, being many of them already reported and related to virulence in other bacteria and classified as moonlighting proteins, which are proteins that have a well-defined function usually in the cytosol, but were also found performing completely different functions in other cellular regions, mostly on the surface. Such proteins may be related to biofilm production, defense response against the host, adhesion of bacteria to surfaces, and various other functions. Studies in recent years have tried to unravel their possible recognition mechanisms inside the cell and how they are secreted out, as well as trying to understand what functions they have when they are on the surface. In this work, the topics mentioned above were addressed in detail and the possible relationship of surface moonlighting proteins with the virulence of the citrus canker-causing bacteria was discussed.