Endopathogenic lifestyle of Pseudomonas savastanoi pv. savastanoi in olive knots.
Bottom Line: The endophytic phase of Pseudomonas savastanoi pv. savastanoi in olive stems and the structural and ultrastructural histogenesis of olive knots have been studied.Hypertrophy of the stem tissue was concomitant with the formation of bacterial aggregates, microcolonies and multilayer biofilms, over the cell surfaces and the interior of plasmolysed cells facing the air-tissue interface of internal opened fissures, and was followed by invasion of the outer layers of the hypertrophied tissue.This is the first real-time monitoring of P. savastanoi disease development and the first illustrated description of the ultrastructure of P. savastanoi-induced knots.
Affiliation: Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus de Teatinos s/n, E-29071, Málaga, Spain.Show MeSH
Related in: MedlinePlus
Mentions: To visualize the organization of P. savastanoi pv. savastanoi cell clusters during their endopathogenic phase in greater detail, cross‐sections of olive knots induced by NCPPB 3335‐GFP at 35 dpi were examined by scanning electron microscopy. Small groups (Fig. 6A and B) and microcolonies (Fig. 6C) of rod‐shaped bacterial cells, about 0.5 µm wide and 1–2 µm long, were visualized attached to each other and to the surface of hypertrophied host cells by an extracellular fibrillar matrix. However, the majority of the bacterial cells were found forming biofilms composed of a multilayer of bacterial cells. Biofims were observed colonizing the surface (Fig. 6D) and interior of plasmolysed host cells (Fig. 6E).
Affiliation: Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus de Teatinos s/n, E-29071, Málaga, Spain.