Xanthomonas gardneri is a gram negative aerobic bacteria with a polar flagella. It is found primarily in association with plants (disease lesions and soil) and is an important plant pathogen for processing tomatoes in Central Brazil and United States. Despite the many reports describing Xanthomonas campestris pv. campestris, including the recent sequencing of its genome, little is known about X. gardneri. Here we describe the extraction of xanthomonadins, a diagnostic pigment for Xanthomonads from X. gardneri. Because Arabidopsis thaliana is the most well studied plant model, we have investigated if it can be a host to X. gardneri. The postulate of Koch has been confirmed and Arabidopsis thaliana can now be added to its list of host plants. Different enzymatic activities including cellulase, xylanase, pectinase, α-arabinofuranosidase and invertase in the presence of different substrates were tested at various timepoints. Both cellulase and α-arabinofuranosidase activities have been detected. The enzymatic activities tested can possibly play a role during the plant-pathogen interaction.