Surface physicochemical properties at the micro and nano length scales: role on bacterial adhesion and Xylella fastidiosa biofilm development.
The phytopathogen Xylella fastidiosa grows as a biofilm causing vascular occlusion and consequently nutrient and water stress in different plant hosts by adhesion on xylem vessel surfaces composed of cellulose, hemicellulose, pectin and proteins. Understanding the factors which influence bacterial adhesion and biofilm development is a key issue in identifying mechanisms for preventing biofilm formation in infected plants. In this study, we show that X. fastidiosa biofilm development and architecture correlate well with physicochemical surface properties after interaction with the culture medium. Different biotic and abiotic substrates such as silicon (Si) and derivatized cellulose films were studied. Both biofilms and substrates were characterized at the micro- and nanoscale, which corresponds to the actual bacterial cell and membrane/ protein length scales, respectively. Our experimental results clearly indicate that the presence of surfaces with different chemical composition affect X. fastidiosa behavior from the point of view of gene expression and adhesion functionality. Bacterial adhesion is facilitated on more hydrophilic surfaces with higher surface potentials; XadA1 adhesin reveals different strengths of interaction on these surfaces. Nonetheless, despite different architectural biofilm geometries and rates of development, the colonization process occurs on all investigated surfaces. Our results univocally support the hypothesis that different adhesion mechanisms are active along the biofilm life cycle representing an adaptation mechanism for variations on the specific xylem vessel composition, which the bacterium encounters within the infected plant.
Departamento de Física Aplicada, Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil.
Gabriela S
GS
Lorite
Richard
R
Janissen
João H
JH
Clerici
Carolina M
CM
Rodrigues
Juarez P
JP
Tomaz
Boris
B
Mizaikoff
Christine
C
Kranz
Alessandra A
AA
de Souza
Mônica A
MA
Cotta
D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism*; D001422:Bacterial Adhesion / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D002482:Cellulose / Q000737:chemistry / Q000378:metabolism; D018625:Microscopy, Atomic Force; D036103:Nanotechnology; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism*; D012825:Silicon / Q000737:chemistry / Q000378:metabolism; D013499:Surface Properties; D044167:Xylella / Q000254:growth & development* / Q000378:metabolism*
D018829:Adhesins, Bacterial; D011108:Polymers; D002482:Cellulose; D012825:Silicon