congresos y reuniones científicas
COMPENSATORY BALANCE BETWEEN EXTRACELLULAR MATRIX COMPONENTS OF BACTERIAL BIOFILMS DETERMINES RESISTANCE TO ENVIRONMENTAL STRESSORS
LAMI, MARÍA JESUS; ADLER CONRADO; COSTA GUTIERREZ SB; MARTINEZ-GIL M; QUESADA JM,; VINCENT, PAULA; ESPINOSA-URGEL M; DE CRISTOBAL RE
Congreso; SAIB; 2013
Within a biofilm, bacteria are embedded in a complex extracellular matrix that serves at least for two purposes: providing robustness and stability to the biofilm and protecting the cells against a variety of external aggressions. In Pseudomonas putida, two large secreted proteins, LapA and LapF, are key elements with distinct roles. LapA is essential for irreversible attachment to biotic and abiotic surfaces, while LapF is involved in cell?cell interactions, microcolony formation and a mature biofilm development. It was suggested that these surface proteins could be interacting with different exopolysaccharides (EPSs). We report the existence of a compensatory effect where P. putida reacts to the lack of either LapA or LapF by increasing the expression of the specific EPS encoding genes and the consequent protein synthesis. In spite of this compensatory effect, both mutants showed reduced attachment, microcolony development and biofilm formation. However, lapA and lapF mutants showed high resistance to a variety of antibiotics, detergents and saline stress, also displaying competitive colonization in the corn rhizosphere. Our data confirm the role of exopolysaccharides in stress protection and indicate the existence of an ?allostasis? mechanism by which bacteria would sense and counteract alterations in the composition of the extracellular matrix.