P. Syringae ( Pseudomonas syringae syringae , TAX: 208964) is a Bactérie S of the Pseudomonas which is a complex more than cash 60 species in stick, very with negative Gram and provided with Flagelle S polar, able to multiply on varied mediums.

Certain stocks of Pseudomonas are symbions of plants and the microflora of the ground, but under certain conditions, some Pseudomonas are pathogenic mortals for the animal and the Man, which explains why part of the data on P. Syringae are published by medical checks (Example)

Description

P. Syringae : Like all the Pseudomonas (except one), P. Syringae is very mobile thanks to Flagelle S (or lashes) polar. Recluse, in small groupings, or present in Biofilm, it is not very demanding and ubiquist. A battery of Enzyme (Gélatinase, Collagénase, Lécithinase, Protease S, Élastase, and for some types saprophytes or pathogenic opportunist of animals; Arginine dihydrolase) indeed enable him to dissolve and to digest a large variety of substances and organic matters which it finds in the ground or water, on the surface of the sheets or in the cells of plants as it can there introduire.
P. Syringae can under certain conditions of producing pigments having an oxydase, but unable to ferment the glucose.
It produces exotoxins (Toxine S extracellular), whose exotoxin S and exotoxin have, near to the diphteric toxin (evolutionary convergence) detected at 90% of the stocks of P. aeruginosa , and whose production is exacerbated when the bacterium does not have iron). These toxins inhibit the proteinic synthesis of the infected cell, by killing it. The pseudomonas produce also endotoxines and often, but not always (and that depends in particular on the culture medium) of the toxic Pigments or with antibiotic properties which defend them against of others pseudomonas. These endotoxines is: Fluorescein (= Pyoverdine) (pigment yellow-green, water soluble), Phenazine S, Pyocyanin, (pigment blue-green, soluble in the Chloroform), Pyorubine (brown pigment), Oxyphénazine (product breakdown of pyocyanin).

Dynamics of the populations

P. Syringae is famous not very active in summer or by very great colds, but it is nevertheless sometimes abundant on the surface of the sheets in summer.
Il would be mainly diffused by the wind and the rain, in particular in windy, cold and very wet weather at the end of winter and the beginning of spring, in moderate zone. It is at this period that the contagion would be maximum, without need for animal vector or inoculator.

Equipped with an external membrane resistance to the Ultraviolet S and the Oxidant S, and impermeable with many Antibiotic S, this bacillus is famous being a strict Aérobie. (It would however be advisable to check that certain stocks of P. Synringae did not inherit other stocks a capacity to extract Oxygen from Nitrate S (NO3) from the ground or in solution, which would make then them also able to breathe nitrate (Some Pseudomonas do it without difficulty in experimental condition, in a Gélose enriched in nitrates). Knowing that the grounds and water and even the air are increasingly rich in nitrates lost by the sewer S, purification plants and especially by the agricultural Engrais, and knowing that downtown, certain feet of trees are abundantly sprinkled with urine and of excrements, dogs mainly, this property could have an importance, the more so as since 1980s, several stocks of Peudomonas were applied to cereal seeds or directly to the grounds to compete with other pathogenic microbes and mushrooms.
La production of pyoverdine at certain pseudomonas tested, is doped by a high percentage of Phosphate, which is another product (manure, often containing radioactive residues and of Cadmium; two factors of stress for the plant) that agriculture uses massively. Lastly, some pseudomonas are able to benefit from nitrogen the oxides to extract the Dioxygène from it, but, the nitrogen oxides are also pollutants very present in the cities and suburbs, emitted by the vehicles, the heating and agriculture périurbaine.

Habitat

The Pseudomonas are a broad group and very ubiquist. Being satisfied with little and being able to nourish itself on many substrates, this bacterium multiplies until in very poor environments (until in Bi-distilled water!). One finds some in the ground, the air and fresh water, salted and Saumâtre S thus and on many surfaces (vegetable in particular). One found some in the air until in the clouds (where the wind transports them and where they seem to play a part for the nucleation of the water drops, but especially in the crystal formation of ice).
De many Pseudomonas plays an important role for the fertility of the ground, in particular by dissimilating nitrogen oxides and by limiting the populations of bacteria or mushrooms pathogenic. Pseudomonas spp. fluorescent seems to be symbions of the plants in the Rhizosphère, but survives badly in context of intensive agriculture. Certain variable of P Syringae are effective in biological fight. They are implied in particular in the cycle of the Fer and the Azote, and seem to contribute to push back the other pathogenic ones.

Presence

Four hundred stocks of Pseudomonas syringae were analyzed before the end 2006 only in Belgium, on the basis of phenotypical nature (phytotoxines, sidérophores and Bactériocines), and on genetics bases (analyzes of the type PCR which revealed a hundred different profiles, making it possible to differentiate the stocks enters and within the Pathovar S).

P. syringae was found almost everywhere, with a broad interspecific diversity, of which genetic in those of the Verger S of Poirier, Cerisier soft, acid cherry tree and Prunier which was studied in the Belgian areas of Gembloux and of Gorsem. Both principal pathovars of the species known on these cultures (pathovars syringae and morsprunorum, two races of the pathovar morsprunorum), but also various stocks of unspecified Pseudomonas syringae of pathovars and atypical Pseudomonas viridiflava were identified 169 times in these orchards, with varied damage and symptoms, sometimes serious.

Starting from 235 collections in fruit-bearing orchards in all the Wallonia, of the tests by Bio-PCR made it possible by ex to gather 501 new stocks of the group Pseudomonas syringae (for 41 new stocks of Erwinia will amylovora).
Source

The case of the Canker of the Chestnut tree (Historical)

The bacterial canker of the chestnut tree is a emergent Maladie with the probably multiple causes. It was initially believed that a succession of very soft winter, hot summers and wet springs and other factors (pollution, contamination by the size, etc) had supported the infections of chestnut trees by pathogenic organizations close to mushrooms, pertaining to the complex Phytophthora found in cankers observed since the end of the year 1990 on various species of trees. But in 2005, whereas with the the United Kingdom, the Commission of the forests (Forestry commission) estimated that 35.000 to 50.000 trees were sick and several thousands already died of this new disease, the analysis of attacked fabric samples (coming from the south of England) systematically highlighted a complex of bacteria Pseudomonas syringae . In the Hampshire, on 230 studied chestnut trees, approximately 50% presented symptoms of the disease. Three species at least are touched, and where young chestnut trees were planted in the place of those which died, they presented traces of the infection in a few years.

With the Netherlands in 2005, bacteria Pseudomonias syringae were also found on the studied sick trees. In the same way with Brussels and in all central Belgium in 2006 (but not in the South-east of the country (the Belgian Ardennes and Gaume) where the chestnut trees seem curiously saved by the disease). These " P. syringae" seem close to the agent of the bacterial Chancre to the cherry tree and other fruit-lofts (bacteria which are one of the main subjects of research of the laboratory of bacteriology of the Walloon center of agronomic research (CRA-W) in Belgium, since the middle of the years 1990. January 11th, 2006, the bacterium is isolated starting from the sick trunks of two chestnut trees from the Avenue from Tervuren in Brussels then several tens of stocks will be isolated starting from 6 sites of Brussels and 11 Walloon sites, which will be studied, including for their genetic prints (by REP-PCR) by the CRA-W (as from January 2006). The setting in culture and the test of these bacteria by the CRA-W showed an unusual virulence on the chestnut tree, and that the infection of cortical fabrics of chestnut trees by the bacterium had caused many cankers as observed at this tree for a few years.

A Dutch group of work ( Aesculaap ) was created when the deterioration of the chestnut trees appeared to be a national problem in the Netherlands. A first program named “Red of kastanje voor Nederland”, which means “To save the chestnut trees of Holland” worked with several cities to chart the progression of the phenomenon, before launching in 2005 a national survey, for in particular identifying the pathogenic ones potentially causes some and judging a possible co-responsibility of mineuse chestnut tree, invasive recent in the affected areas by the canker. One studies the biochemical processes of the infection, and in Houten, of the lesions were treated in experiments with various products to test their capacity to treat the disease. Wood samples, of bark, flowers, roots and of ground are gathered studied, as well as natural defenses of the chestnut tree to produce possible means of fight and practical advices. The researchers also check that the bacterial cankers found on other species of tree are not due to infections by P. syringae. Whereas the number of affected regions increased in the country and in Europe, a new program “Behoud of kastanje” (“To preserve the chestnut tree”) was launched in 2006, associating more half of the cities of the country (chart). The researchers confirmed there that Pseudomonas Syringae was quite responsible for this disease. He studies natural defenses of the chestnut tree and the factors of stresses which could support the disease and continuous to seek solutions. In the United Kingdom, the Forestry review & British Timber, also concluded, in March 2006 (p20), that P. Syringae is almost certainly the person in charge of the disease and not the mushrooms will phytophtora as one had initially believed. In several countries, the identification of stocks presenting of the particular characteristics is in hand, as well as phylogenetic analyzes.

Everywhere, it seems that the majority of the first sick and dead trees are old from 10 to 30 years. P. syringae were found (be 2006 in Brussels) in cortical fabrics of older chestnut trees, but which do not seem to induce of canker. The zone starting of epidemic of canker of the chestnut tree are often zones of pollution industrial, urban, automobile and agricultural, and for the case of the fruit-lofts, and of the Marronnier S), it seems that the sick trees are often trees stressed or badly planted (in the 10 to 30 last years), or having all the same seedbeds like origin; the fact that they are infected the first pleads for a anthropic responsibility. Some atypical cases (old chestnut trees touched in one of the isolated private parks…) could also be explained by a contamination carried by tools not disinfected at the time of cuts or sizes of maintenance the previous years (Pseudomonas is moreover, known to resist some disinfecting).

A possible dispersion increased by the Mineuse of the chestnut tree is studied since 2006.

Symptoms

At the chestnut tree, cherry tree or fruit-lofts: the Symptôme S are many and atypical if they are taken separately: débourrement slowed down then blocked, followed by a drying of the sheets and barks or flowers, with various heights or various stages of vegetation, which involves a delay or stop of the growth. Only one Rameau can be touched, or one or more branch (S) main (S) or all the tree (including the roots for example in the case of the Nectarine infected by or all the plant (in the case of annual). Spots and necrose are formed on the sheets (spots of very diverse appearances according to the stocks and the hosts concerned). According to certain authors, the attacks on the sheets often occur after strong rains and of the strong gales.

The Dessiccation is accompanied or preceded by Nécrose S Chancre use from where a brownish Exsudat with reddish runs out. The cankers from where runs a dark exsudat are one of the most characteristic symptoms. They are often accompanied by long vertical slits (at the chestnut tree) and/or by an separation of the bark at the trees. Under the bark of the reddish spots to brownish develop. Sometimes important castings of exsudat color the bark, marking a flow along the trunk, with a diffusion horizontal on the microphone Algue S and micro Lichen S épiphytes for examples. Various Mushroom S opportunist or Insecte S Saproxylophage S can then colonize sick or dead wood. In the years 2000-2006, the presence of cankers with flows on trees from 10 to 20 years systematically seem to announce the death of the tree, often in 1 year or two. Rem: Possible confusion with Pseudonomas viridiflava .

Virulence

Very the many variable ones (Phenotype S) of this bacterium probably exist. More than 40 Pathovar S is known, even very studied because causes important economic losses by attacking various Fruit S and Légume S (ex: Tomato, Tobacco, Cucumber, Bean, Apricot, Apple, Pear, Lemon-yellow, Soya. Its effects were also studied at a model plant of laboratory; the Arabidopsis. Each Pathovar is indicated by the initials statement. and a name and number (Ex: P. syringae statement. syringae B728a ) which attacks bean.
Pour the majority of the studied plants one finds cultivars resistant to P. syringae .
Il does not have yet a consensus there on the processes of Infection and Contagion. In the case of the cultivated annual plants, it is thought that the Bacille is present in the ground or on seed, that it colonizes initially the outside of the plant (Phylloplane). It can infect the cells of surface (it is then pathogenic) or simply colonize the phylloplane in manner épiphyte without damaging the plant which is not whereas a support. It can in both cases penetrate by wounds (or by the Stomate S of the sheets?). The bacillus can then start a second phase of growth in the Apoplaste (the whole of intercellular spaces of the sheet, of the skin of the fruit), or in subcortical fabrics (under-bark) when it is about a tree. Certain authors evoke also infections racinaires.
Une team at least works on the assumption of a complex interaction between bacillus-insect-host.
Les plants which resist Pseudomonias pathogenic can start a cellular programme of suicide its involved. But some pathovars seem able to inhibit this program. The populations of this bacillus Co-evolve/move with many plants since probably very a long time. It is possible that the establishment of contact between bacilli and plants which knew a divergent evolution on different continents supports stocks which appear highly virulent, for lack of protection genetically programmed among their hosts, but Ca does not remain in 2006 qu ' an assumption.

At the annual plants the damage can be important in wet and fresh period, and is stopped with the arrival of the beautiful season. Since the Nineties, with a strong aggravation in the years 2000, some particularly virulent stocks of P. Syringae seem responsible for mortality important of horse chestnut trees in the center of Western Europe. Studies were undertaken in 2006 for better including/understanding this new virulence on the chestnut tree, but of the former studies concerning of other target species continue (ex Berkeley, Cornell University (the USA), Université of Wisconsin (the USA), CPU-Riverside (the USA) with INRA in France or Belgium, and elsewhere, certain researchers pleading for a Séquençage of various stocks to identify genes implied in the virulence of the bacillus and to produce fast tests in the form of biochips ( microphone-array ) identifying the stocks of the bacterium. Within the same target species-host, there exist Génotype S which protect certain stocks from plants against this bacterium. The Université of Berkeley identified many genes which are expressed only when the plant is on a plant or infects it, and not in culture medium. These genes play a role still unknown or badly included/understood.

According to work of Dr. Matthias Ulrich, University of Bremen (Germany), it seems that a Protéine made up of two elements of the bacterium can change form when the temperature drops. This molecule would play at the same time the part of a Thermostat which would activate the gene which orders the production of coronatine which is phytotoxique, at the time when the plant is more vulnerable there when the weather is cold and gray.

Enough different from the species-type Pseudomonas aeruginosa a sub-type bacterium seems to attack only one species of plants, even with a subpopulation having genetic characteristics of susceptibility to this particular Pseudomonas. It can also develop on them in épiphyte, without posing apparent pathological problem. A chestnut tree which seems healthy can be seriously touched the year following and died two years later.

Genetics

The genome of '' Pseudomonas syringae statement. tomato DC3000 '' was sequence, just as that of P. Putida and P. aeruginosa (available in 2006 on Internet on the database genetics KEGG) (see also http://leah.haifa.ac.il/~hosid/Curved_Promoters/Table1.html) The pathovar Psy B728a decoded in 2005 lays out

Rem: the majority of the pseudomonas are Lysogène S or multilysogenes, i.e. them Génome contains one or more genomes of virus, which would be one of the explanations of the virulence of certain stocks, and of their facility to be transferred.

Work is in hand on the stocks which decimate the chestnut trees in certain parks, gardens or urban areas in the center of Western Europe.

Habitat

This bacterium is normally and largely present in the Environnement in moderate zone. One finds it on many plants, pathogenic or not according to the stock and the plant species which can be or not protected some.

Pseudomonas are considered to appreciate the fresh and/or wet environments. One can find them in the ground, in fresh water, salted or brackish and thermal as on the surface of the sheets. They would be less present in water rich in organic matters, in particular stagnant, probably because of the competition of other more adapted species, supporting lower oxygen rates.

One found some until in the clouds. The road wind, rain and spray are famous capacity to disperse it. Present in the rain water tanks, it can during watering of the flower or vegetables to contaminate them (for the species phytopathogenes).

Certain variable pathogenic (Pathovar) are known only in some countries, or were discovered in two opposite points of the planet, of which for example Pseudomonas syringae statement. persicae (see world chart) which one found in Croatia, in France, with the the United Kingdom and in New Zealand. (Recall: nonthe presence on the chart can result from a defect of monitoring or declaration, and relates to only area EPPO).

Phytopathogenicity

When the temperatures are negative the bacterium, by its capacity glacogene seems to be able to penetrate in the buds and/or to cross the barrier of the bark on the branches or the bark of the trunk and to necrose them. According to Vigouroux (1989), the cycles freezing-thawing can also facilitate the penetration of the bacterium. The wounds resulting from the size are easy ways of penetration for Pseudomonas syringae 2 statement persicae on fishing it, especially if the size is made in winter and on sensitive fabrics by tools polluted by bacterium (Luisetti and Al, 1981). In spring, starting from the contaminated bodies, the bacterium can colonize the surface of the bark and the sheets in épiphyte (Gardan and Al, 1972), with a possible production of foliar spots supporting in spring of important a Inoculum. They would be however the sheets and the petioles, abundantly colonized by the bacterium in autumn, which would be the inoculum responsible for the lesions carried out through the petiolar wounds. It should be noted that the illumination by delaying the fall of the sheets could perhaps have an impact on the cicatrization of the petiolar wounds.

P. Syringae is usually found in épiphyte on the sheets without it infecting this one. It must penetrate the interior of the cells to become pathogenic. It could perhaps also be opportunist (as in the Man or the animal) and benefit from wounds, of cracks in the barks before inhibiting the natural mechanisms of defense of the plants which are sensitive there. Could the capacity of Pseudomonas to produce white frost before the temperature does not go down to zero degree help it to infect certain plants? That remains to be cleared up.

Use

Some nonpathogenic stocks of pseudomonas are used in biological Lutte to protect certain fruits in antagonist from the micro-organisms which cause Moisissure S and the Pourriture. At least two stocks of Pseudomonas are sold like bio-fungicides . The stock P. syringae ESC-11 (in the past named L-59-66) sold under trade name BioSaveTM 110 is used to protect pears and apples, after harvest. P. syringae ESC-10 is sold under the name of BioSaveTM 100 to control the rot of collected lemon. A research program of the European commission n° QLRT-2001-00914 aims at exploring different genomes from these bacteria for better using them.

This bacterium present in the air plays a part in the appearance of Neige or the Givre at a temperature close to 0°C. Several stocks of P. syringae were used in experiments then industrially by the Industry of the Biotechnologie S for their capacity with nucléer the water drops to form a crystal core of ice when the temperature approaches 0 °C, for example, in the form of lyophylized bacteria for the production of artificial snow for the tracks of Ski or the cinema. A Snomax commercial product is sold for this purpose.
One thus created artificial islands of ice to facilitate oil drillings on the Arctic Ocean.
On planned to use Pseudomonas as activator of nucleation of ice to produce in winter of enormous blocks of ice which could be used in summer for the Climatisation of large industrial buildings, offices, Patinoire S. to even accelerate - while consuming less electricity - the congelation of various food, of which frozen emulsions (Ice cream for example).

The industry of biotechnology is interested in particular in the genome of Pseudomonas fluorescens .

Resistance to antibiotics

Pseudomonas are known for their ''' multirésistance with disinfectants and many antibiotics '''. P. Syringae resists many bacterial inhibiters: For example, a change (acquired or spontaneous?) with the Rifampicine was found at a stock infecting beans in Wisconsin. Various Pseudomonas resists many chemical agents disinfecting, continuing even to grow and to reproduce in certain solutions disinfectants or of the environments usually biocides such as the water of the swimming pools, the antibiotic or disinfectant solutions (chlorehexidine aqueous, éosine, polymyxine B, Cétrimide) and even ...... liquid soap). This is why the Pseudomonas which infect the Man and the animal are classified with high-risk of nosocomial, in particular P. aeruginosa .
Cette resistance is it natural or acquired? One is unaware of it, but this common bacterium in water is frequently in contact with residues of disinfecting, biocides and antibiotics, which can have generated multiple selective adaptations. Resistance comes from phenomena of proofing of the external membrane to these molecules (modification of the porines) and/or to the production of enzymes inactivantes. In the USA in particular, antibiotics such as streptomycine and oxytetracycline were used during 40 years like phytopharmacological, primarily at the time of flowering, against the bacteria developing on fruit-lofts or fruits, (what could contribute to select resistant stocks) <>McManus. 2000. Antibiotic uses and microbial resistance in seedling agriculture. ASM News 66 (8): 448-9<>Vidaver AK. 2002. Use antimicrobials in seedling agriculture off. Clin Infect Say 34:5107 - 10.

Means of fight

One does not know any yet which is effective for a chestnut tree already infected. For the reasons evoked above, the Antibiotique S which were used on fruit-lofts are not recommended (or prohibited), and in any event a priori useless at the plants once the infection is advanced. Their use is likely quickly to cause the appearance of resistant stocks.

P. Syringae apparently usually opportunist, i.e. infecting plants is already weakened by pollution, a hydrous stress, bad conditions of plantation, another disease, wounds, a constrained or asphyxiated system racinaire.
On lack still of data to confirm it or cancel it, but restore an environment (water, air, ground) of quality seems useful on suspicion, just as to plant in deep grounds corresponding to the needs for the plant, with a sufficient water capacity.

Cupric pulps (containing Cuivre) are sometimes used on the trees with the fall of the sheets, but at least certain stocks are resistant to copper thanks to a protein which traps and inert copper.

Precautions

This bacterium is considered to require alive cells to live, without thus being able to survive in the deadwood. To burn this last would not be used then for nothing. On the other hand the transport of logs, branches, sheets dead or coldly cut sick trunks could contribute to diffuse the bacterium, which in addition seems nevertheless able to diffuse itself by the wind and the rain. Better is worth to perforate wood and sheets on the spot, possibly under a layer of ground of 10 cm for the sheets and the barks. One can take care on suspicion of the good conditions of development of the tree. The chestnut tree is in the beginning a forest tree which appreciate a ground rich in Humus and a place sufficient for its development racinaire.

The Agency of research of the English commission of the forests recommends not to replant chestnut trees where others died not very front, the experiment showing that they fall sick in a few years.

The red chestnut tree and the white were shown also sensitive to the bacterial canker, other species are in the course of evaluation (in 2006-2008).

The stressed bacteria being able to exchange some their genes, one can ask for so certain uses of Pseudomonas were well evaluated from the point of view of the risks.

Bacteriological characters

Microscopic morphology

The Pseudomonas are negative bacilli Gram , ends, rights and very mobiles thanks to a Flagelle (S) polar (S): ciliature monotriche. They are deprived of spores and capsules. They appear generally isolated or in Diplobacille S.

Characters of culture

Conditions of culture

They develop on all the usual mediums, even simplest, while being very thermically tolerating around an optimum of growth of 24-35°C (Mésophile) in culture, but supporting a broad fork of temperature: 4 with 42°C even more temporarily. A relative cold slows down to them Métabolisme, more or less according to the species or variable the genetics seems it. Stocks known as Psychrophile S reproduce at low temperature (from 4°C). Their growth is not completely blocked by the winter nor by the refrigeration. They are killed with the microwave which allows the disinfection of the gloves and fabrics.

Culture media used

• nonselective Milieux
• ordinary Gélose
• Gélose BCP
• peptonée Eau
• selective Milieux
• Gélose cétrimide
• Milieu of King has
• Milieu of King B

Biochemical characters

Metabolism

P. Syringae reduces a Oxydase and it degrades the Glucose by the way of Entner-Doudoroff, like all the Pseudomonas . Fluorescence under UV, which characterizes the Pseudomonas is one of the means of detecting it and of quantifying.

Production of pigments

Many representatives of this kind produce a Pigment. Let us quote those used for the identification: Like many Pseudomonas, P. Syringae produces Pyoverdine (green fluorescent, water soluble). It thus belongs to the group known as fluorescens .

Sources and references

Internal bonds

• Pseudomonas

External bonds:

• Photo

  of the bacillus, under the electron microscope, on French bean sheet ('' Phaseolus vulgaris '')

• Page of the INRA with photographs of the symptoms
• L P S NR
• Photographs of infected plants (of which under the microscope in fluorescence)
• Canker on '' Acer rubrum ''
• Damage on willow
• Damage on olive-tree, of with '' Pseudomonas syringae subsp. savastanoi statement. nerii ''
• Pseudomonas like bio-pesticide
• a pseudomonas discovered at the same time in France and New Zealand
• Gate of data on the genome of the pathovar Psychological B728a (publication 2005)
• Sequencing of '' Pseudomonas syringae phaseolicola1448A '' by Center for Biological Sequenceanalysis.
• Pseudomonas syringae statement. mori and mulberry tree of the worms with silk.

Literature:

• Pseudomonas Syringae and Related Pathogens: Biology and Genetic , Cindy E. Morris, Alan Collmer, David E. Stead, Giuseppe Surico, Jesus Murillo, John W. Mansfield, Matthias S. Ulrich, N.S. Iacobellis, N.W. Schaad, Steven W. Hutcheson. ED: Kluwer Academic Pub (August 1st, 2003) (SBN: 1402012276)

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