INVESTIGADORES
GIORDANO Walter Fabian
congresos y reuniones científicas
Título:
Cell autoaggregation, biofilm development, and plant attachment in a Sinorhizobium meliloti lpsb mutant.
Autor/es:
BOGINO, P., SORROCHE, F., MORALES, G., GIORDANO, W.
Reunión:
Encuentro; Sexto Encuentro de Física y Química de Superficies.; 2014
Resumen:
Bacterial surface
molecules are crucial for establishment of successful rhizobia-legume
symbiosis, and in most bacteria are also critical for adherence properties and
surface colonization [1,
2]. Mutants defective in the production of exopolysaccharides (EPS),
lipopolysaccharides (LPS), and capsular polysaccharides are usually affected in
the process of root infection [3]. Here we evaluated the role of LPS in cell-cell and cell-surface interactions. Using Confocal Laser Scanning Microscopy (CLSM) the progression of biofilm
development of GFPuv-tagged, EPS II-producing strains Rm8530 (wild type) and
Rm8530 lpsB (LPS mutant), was
determined. Biofilm formation was perturbed in Rm8530 lpsB, as compared to parental strain Rm8530. EPS II seems to be
essential for the development of the ordered bacterial honeycomb-like arrays of
the wild type strain, in which the rods adhere to each other through lateral
interactions, forming rows of bacteria identically oriented. Despite that
Rm8530 lpsB is able to synthesize EPS
II, such structures were not visualized in mutant biofilms. Experiments combining theLPS and EPS mutants were able to showthat both polymers have an
impact in cell-cell adhesive interactions leading to autoaggregation. Polar bacteria-bacteria adhesive interactions were
increased in Rm8530 lpsB as compared
to Rm8530 and typical zig-zag or bacterial bouquets formations were
visualized only in the mutant. These observations indicate that the LPS has a
role in determining cell-cell interactions. Such interactions were also detected
when these strains were imaging by Atomic Force Microscopy (AFM). An altered LPS molecule increased
bacterial adsorption to roots. Our findings clearly indicate that mutants in the core of LPS showed alterations
in the formation of biofilmsand adhered to alfalfa roots in greater numbers than the wild strains withLPS, whereas the increased autoaggregation in these mutants was evident in
the absence of EPS II.