''Pseudomonas savastanoi'' is a

gram-negative Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists ...

plant pathogen Plant diseases are diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like orga ...

bacterium Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the ...

that infects a variety of

plant Plants are the eukaryotes that form the Kingdom (biology), kingdom Plantae; they are predominantly Photosynthesis, photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with c ...

s. It was once considered a

pathovar A pathovar is a bacterial strain or set of strains with the same or similar characteristics, that is differentiated at infrasubspecific level from other strains of the same species or subspecies on the basis of distinctive pathogenicity to one o ...

of ''

Pseudomonas syringae ''Pseudomonas syringae'' is a rod-shaped, Gram-negative bacterium with polar flagella. As a plant pathology, plant pathogen, it can infect a wide range of species, and exists as over 50 different pathovars, all of which are available to research ...

,'' but following DNA-relatedness studies, it was instated as a new species. It is named after Savastano, a worker who proved between 1887 and 1898 that olive knot are caused by bacteria.George M. Garrity: ''

Bergey's Manual of Systematic Bacteriology ''Bergey's Manual of Systematic Bacteriology'' is the main resource for determining the identity of prokaryotic organisms, emphasizing bacterial species, using every characterizing aspect. The manual was published subsequent to ''Bergey's Manual ...

''. 2. Auflage. Springer, New York, 2005, Volume 2: ''The Proteobacteria, Part B: The Gammaproteobacteria'' The pathovar of greatest economical significance is ''Pseudomonas savastanoi'' pv. ''savastanoi'', which causes the disease

olive The olive, botanical name ''Olea europaea'' ("European olive"), is a species of Subtropics, subtropical evergreen tree in the Family (biology), family Oleaceae. Originating in Anatolia, Asia Minor, it is abundant throughout the Mediterranean ...

knot. Symptoms include formation of

galls Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants. Plant galls are abnormal outgrowths of plant tissues, similar to benign tumors or wart ...

on infected trees; tumour formation is induced by indoleacetic acid biosynthesis by the bacteria, in a similar manner to the well-studied crown gall pathogen, ''

Agrobacterium tumefaciens ''Agrobacterium tumefaciens'' (also known as ''Rhizobium radiobacter'') is the causal agent of crown gall disease (the formation of tumours) in over 140 species of eudicots. It is a rod-shaped, Gram-negative soil bacterium. Symptoms are cause ...

''.Hosni T, et al. 2011. Sharing of quorum-sensing signals and role of interspecies communities in a bacterial plant disease. ISME J. .

History

One of the first scientists to carry out scientific and modern research on the disease of

olive trees The olive, botanical name ''Olea europaea'' ("European olive"), is a species of subtropical evergreen tree in the family Oleaceae. Originating in Asia Minor, it is abundant throughout the Mediterranean Basin, with wild subspecies in Africa ...

caused by ''Pseudomonas savastanoi'' () was Giuseppe Maria Giovene (1753-1837), who explained his conclusions in his publication ''Sulla rogna degli ulivi'' (1789).

Pathovars

* ''Pseudomonas savastanoi'' causes ash bacterial canker.Smith, Dunez, Lelliot, Phillips and Archer (1988) European Handbook of Plant Disease. Blackwell Scientific Publications. * ''Pseudomonas savastanoi'' attacks

oleander ''Nerium oleander'' ( ), commonly known as oleander or rosebay, is a shrub or small tree cultivated worldwide in temperate and subtropical areas as an ornamental and landscaping plant. It is the only species currently classified in the genus ...

. * ''Pseudomonas savastanoi'' causes

knot. * ''Pseudomonas savastanoi'' attacks ''

Phaseolus ''Phaseolus'' (bean, wild bean) is a genus of herbaceous to woody annual and perennial vines in the family Fabaceae containing about 70 plant species, all native to the Americas, primarily Mesoamerica. It is one of the most economically importan ...

'' (bean) plants B. P Borowicz, A Maćkowiak, H Pospieszny (2002) Improved identification of ''Pseudomonas savastanoi'' pv. ''phaseolicola'' at the molecular level. EPPO Bulletin 32 (3), 467–469.

Quorum sensing

''P. s.'' pv. ''s.'' has an unusual

quorum sensing In biology, quorum sensing or quorum signaling (QS) is the process of cell-to-cell communication that allows bacteria to detect and respond to cell population density by gene regulation, typically as a means of acclimating to environmental disadv ...

dynamic: It shares quorum with an entirely different

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

, the Enterobacterales. Hosni et al., 2011 and Caballo-Ponce et al., 2018 find ''P. s.'' pv. ''s.'' produces very similar ''N''-acyl homoserine lactones (AHLs) to the Erwiniaceae ''

Erwinia ''Erwinia'' is a genus of Enterobacterales bacteria containing mostly plant pathogenic species which was named for the famous plant pathologist, Erwin Frink Smith. It contains Gram-negative bacteria related to ''Escherichia coli'', '' Shigella ...

'' '' toletana'' and '' Pantoea agglomerans''. Hosni find an avirulent mutant – defective for AHL production – is restored to virulence by the presence of ''E. toletana'' and ''P. agglomerans''. These results demonstrate disease enhancing cooperation but also reveal a possible way that undiscovered cheating may be occurring.

References

External links

Type strain of ''Pseudomonas savastanoi'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
Pseudomonadales Bacterial plant pathogens and diseases Fruit tree diseases Pulse crop diseases Bacteria described in 1982 {{Pseudomonadales-stub