Plant cell wall degradative enzymes have attracted great interest of scientists due to their many biological roles and industrial applications such as in biofuels, paper, textiles, food and beverage production processes. However, the depolymerization of plant cell wall by enzymatic routes is neither a fully consolidated process nor economically viable, being necessary the development of new strategies and biochemically more efficient processes. Phytopathogenic organisms, such as fungi and bacteria, have a large arsenal of glycoside hydrolase (GH), enzymes which act on plant cell wall polysaccharides, favoring the infectious process, providing nutrients and mediating plant-pathogen interactions. Therefore, the elucidation of the molecular mechanisms underlying these enzymes is very important not only because of their biotechnological appeal, but also to provide a better understanding of their role in pathogen development as well as in biological events associated with the plant-pathogen interaction. Xanthomonas axonopodis pv. citri (Xac), causative agent of citrus canker, has a large number of GHs, including enzymes from the GH43 family, which are represented by multiple genes, suggesting the existence of functional divergence and distinct biological roles. Besides that, GH43 family is notoriously ubiquitous in plant biomass maceration specialized organisms, acting on the degradation of key polysaccharides that constitute the hemicellulose such as xylan and arabinans. The GH43 family is defined as polyspecific due to its large functional diversity, so this family was latter divided into 37 subfamilies. According to this new classification, several subfamilies remain completely unknown such as the subfamily 9, which is present in Xac's genome. Thus, this project aims to provide a mechanistic understanding of Xac GH43 enzymes using structural, biochemical and cellular approaches that will allow us to infer the roles of these enzymes for the pathogen (either in virulence, signaling, plant-pathogen interaction or nutrition). On the light of these results, we will also be able to estimate the potential biotechnological applications for these enzymes, considering that the GH43 family is still poorly explored and has strong correlation with plant cell wall maceration.
News published in Agência FAPESP Newsletter about the scholarship: