Within the first line of research, we use bacteria of the genus Pseudomonas as a model system. The root-colonizing strain Pseudomonas putida is our model to analyze relevant mechanisms involved in plant-microbe interactions in the rhizosphere, such as the development of biofilms during root colonization, the chemotactic response towards root exudates such as amino acids and Krebs’ cycle intermediates, as well as signaling pathways between bacterial cells or with the plant. We analyse the role of surface determinants (exopolysaccharides, adhesins and other extracellular proteins) in planktonic and sessile bacterial populations, and how the levels and transduction of the second messenger cyclic diguanylate modulates the switch between lifestyles. The human opportunistic pathogen Pseudomonas aeruginosa is our model to study host-pathogen interactions, in particular those required for the infection process, with the ultimate goal of finding new antimicrobial compounds that block such interactions and therefore bacterial virulence. Using these bacteria, we study different mechanisms by which bacteria sense environmental and host signals, including chemosensory pathways, one- and two-component systems, and cell-surface signaling systems. Sensory mechanisms currently studied modulate a number of important bacterial functions like chemotaxis, biofilm formation, stress responses, iron uptake, virulence and synthesis and degradation of antibiotics. The identification of environmental signals which define different features of bacterial physiology, and of the specific signal molecules that interact with the sensor proteins, is a necessary requisite for diverse biotechnological applications.
Our research on biodegradation especially targets mono- and polycyclic aromatic hydrocarbons, nitroaromatics, and polychlorinated aromatic compounds, as well as pesticides, among others. We are looking for novel aerobic and anaerobic pathways, their genetic determinants, and the molecular mechanisms controlling their expression. The objectives include the construction of improved strains through metabolic engineering and the molecular analysis of pathway enzymes and regulatory proteins. We are also interested in the bacterial diversity of polluted and pristine sites to investigate the response of microbial communities towards environmental changes and explore them as a source for new activities of biotechnological relevance using metagenomic approaches.
The biological control of pathogens, pollutant elimination and phytoremediation are potential applications of our research.