Pseudomonas syringae

Cultures of Pseudomonas syringae

Pseudomonas syringae is a gram-negative, rod-shaped bacterium of the genus Pseudomonas. It was isolated in 1902 as a plant pathogen of Commons lilac (Syringa vulgaris). Since it catalyzes the ice nucleating supercooled water which remains liquid down to -40 ° C in absolute purity, up to a temperature of -1.5 ° C, it is in the interest of agriculture and biotechnology.

Features

Pseudomonas syringae is a gram-negative, rod-shaped bacterium and portable. It is strictly aerobic and produced fluorescent pigments on media containing little iron. From other species of the genus Pseudomonas, it is distinguished by a negative response in oxidase and arginine dihydrolase tests, .

Nucleation

A special feature of the bacterium is that intact cells can serve as an organic seed for the formation of water ice. It catalyzes the process up to a temperature of -1.5 ° C. This is very effective so far as the majority of organic or inorganic particles, which are used for nucleation are active below 10 ° C.

Occurrence

Precise distribution information is missing. However, tests show of ice nucleating microorganisms that this ubiquitous on plants ( phyllosphere ) are common. In surveys of 95 plant species was found in almost all Pseudomonas syringae. To what extent is a function of various strains of certain species of plants, must still be investigated.

These microorganisms belong to the ice-forming organisms that may be responsible for the formation of snowflakes and raindrops in clouds. The microorganisms sometimes leave the Phylosphäre and be carried away by the air. So they can also get into the cool high layers of the atmosphere, where they for subcooled water (tiny, -40 ° C to -1.5 ° C but cold liquid water droplets ) are used for nucleation, as you knew it a long time only of solid particles. First as a snowflake, frequently thawed in deeper layers of the atmosphere to a raindrop, P. syringae falls back to earth as precipitation, where the microorganism can colonize new plants.

Of damage

Pseudomonas syringae causes various plant diseases such as canker, wilt or stain. Different tribes, known pathovars, this affected different plant species, including some important crops. Originally 48 pathovar were known. After genetic analysis, however, were many of them associated with other Pseudomonas species. The following pathovars of Pseudomonas syringae are known.

  • Pseudomonas syringae pv aceris affects maples ( Acer)
  • Pseudomonas syringae pv Actinidiae infects Chinese rays stylus ( Actinidia chinensis) and is responsible for a significant drop in production of gold kiwifruit in New Zealand.
  • Pseudomonas syringae pv aesculi infects the Horse-chestnut (Aesculus hippocastanum)
  • Pseudomonas syringae pv aptata infects beet (Beta vulgaris)
  • Pseudomonas syringae pv atrofaciens infests wheat (Triticum aestivum)
  • Pseudomonas syringae pv dysoxylis affects Dysoxylum spectabile
  • Pseudomonas syringae pv glycinea infects soybean ( Glycine max)
  • Pseudomonas syringae pv japonica infests barley ( Hordeum vulgare)
  • Pseudomonas syringae pv Lapsa infests wheat (Triticum aestivum)
  • Pseudomonas syringae pv maculicola infects potatoes (Solanum tuberosum)
  • Pseudomonas syringae pv panici affects Rispenhirsen ( Panicum )
  • Pseudomonas syringae pv papulans affects wood apple (Malus sylvestris)
  • Pseudomonas syringae pv phaseolicola infects bean ( Phaseolus vulgaris)
  • Pseudomonas syringae pv pisi infects peas ( Pisum sativum )
  • Pseudomonas syringae pv syringae infects species of the genera lilac (Syringa ), Prunus and Phaseolus
  • Pseudomonas syringae pv tabaci infects tobacco (Nicotiana )
  • Pseudomonas syringae pv tomato infects tomato ( Solanum lycopersicum ), as Modellpathogen also for studies on the thale cress (Arabidopsis thaliana ) and Nicotiana attenuata is used

Importance in agriculture and biotechnology

Since this bacterium is a cause of frost damage in plants, 1983 Field experiments with strains lacking the gene were ice nucleating (ice ) made ​​in the USA. The aim was to intraspecific competition between the wild- type strain and the mutant strain to promote, thus reducing frost damage in potato plants. This was one of the first deliberate release of genetically modified microorganisms.

Due to its ice-forming properties of the bacterium is also used in the production of artificial snow.

Gammaproteobacteria Pseudomonadaceae Oxidase-Test Drop (liquid) Digital Object Identifier
664046
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