Controlled spatial organization of bacterial growth reveals key role of cell filamentation preceding Xylella fastidiosa biofilm formation

Abstract

The morphological plasticity of bacteria to form filamentous cells commonly represents an adaptive strategy induced by stresses. In contrast, for diverse human and plant pathogens, filamentous cells have been recently observed during biofilm formation, but their functions and triggering mechanisms remain unclear. To experimentally identify the underlying function and hypothesized cell communication triggers of such cell morphogenesis, spatially controlled cell patterning is pivotal. Here, we demonstrate highly selective cell adhesion of the biofilm-forming phytopathogen Xylella fastidiosa to gold-patterned SiO2 substrates with well-defined geometries and dimensions. The consequent control of both cell density and distances between cell clusters demonstrated that filamentous cell formation depends on cell cluster density, and their ability to interconnect neighboring cell clusters is distance-dependent. This process allows the creation of large interconnected cell clusters that form the structural framework for macroscale biofilms. The addition of diffusible signaling molecules from supernatant extracts provides evidence that cell filamentation is induced by quorum sensing. These findings and our innovative platform could facilitate therapeutic developments targeting biofilm formation mechanisms of X. fastidiosa and other pathogens.

Thidiazuron: New Trends and Future Perspectives to Fight Xylella fastidiosa in Olive Trees

“…Xf Wells is a xylem-limited Gram-negative bacterium native to the Americas, which belongs to the family Xanthomonadaceae (Gammaproteobacteria); it is an obligatory colonizer of plant and insect hosts [ 66 ] and is able to form biofilms, the mechanism of which is currently under study [ 67 ]. The first to report on a disease caused by Xf was Newton Pierce in 1892 [ 68 ], whose studies were addressed to PD, an epidemic of vine disease in Southern California that had devastating consequences in the grape industry.…”

Physiochemically Distinct Surface Properties of SU-8 Polymer Modulate Bacterial Cell-Surface Holdfast and Colonization

“…24 In particular, the entire biofilm formation process, starting from single-cell adhesion, has been investigated, turning X. fastidiosa into a reliable bacterial model. 18,25 This species is also interesting as it shares many genetic traits with other human bacteria 26,27 and has a relatively slow duplication time (∼6 h), 28 which renders the observation of surface colonization more straightforward. Moreover, X. fastidiosa relies on type-IV pili, which are about 2-to 6-μm long, for twitching motility; these pili are significantly impacted by surface chemistry.…”

Exploring Active Peptides with Antimicrobial Activity In Planta against Xylella fastidiosa

“…Xylella fastidiosa subspecies pauca strain De Donno was isolated in 2014 from OQDS-stricken olive trees and its complete genome has been sequenced [ 7 , 8 ]. The crucial pathogenic mechanism of Xf depends on biofilm formation causing the obstruction of xylem vessels [ 9 , 10 ]. Within the biofilm, the cells organize their function and behavior to persist in their environment and to survive.…”