Pseudomonas is a genus of Gram-negative, Gammaproteobacteria, belonging to the family Pseudomonadaceae and containing 191 validly described species. The members of the genus demonstrate a great deal of metabolic diversity and consequently are able to colonize a wide range of niches. Their ease of culture in vitro and availability of an increasing number of Pseudomonas strain genome sequences has made the genus an excellent focus for scientific research; the best studied species include P. aeruginosa in its role as an opportunistic human pathogen, the plant pathogen P. syringae, the soil bacterium P. putida, and the plant growth-promoting P. fluorescens, P. lini, P. migulae, and P. graminis.
An endophyte is an endosymbiont, often a bacterium or fungus, that lives within a plant for at least part of its life cycle without causing apparent disease. Endophytes are ubiquitous and have been found in all species of plants studied to date; however, most of the endophyte/plant relationships are not well understood. Some endophytes may enhance host growth, nutrient acquisition and improve the plant's ability to tolerate abiotic stresses, such as drought, salinity and decrease biotic stresses by enhancing plant resistance to insects, pathogens and herbivores.
Diazotrophs are bacteria and archaea that fix atmospheric nitrogen gas into a more usable form such as ammonia.
Paenibacillus is a genus of facultative anaerobic, endospore-forming bacteria, originally included within the genus Bacillus and then reclassified as a separate genus in 1993. Bacteria belonging to this genus have been detected in a variety of environments, such as: soil, water, rhizosphere, vegetable matter, forage and insect larvae, as well as clinical samples. The name reflects: Latin paene means almost, so the paenibacilli are literally "almost bacilli". The genus includes P. larvae, which causes American foulbrood in honeybees, P. polymyxa, which is capable of fixing nitrogen, so is used in agriculture and horticulture, the Paenibacillus sp. JDR-2 which is a rich source of chemical agents for biotechnology applications, and pattern-forming strains such as P. vortex and P. dendritiformis discovered in the early 90s, which develop complex colonies with intricate architectures as shown in the pictures:
Paenibacillus polymyxa, also known as Bacillus polymyxa, is a Gram-positive bacterium capable of fixing nitrogen. It is found in soil, plant tissues, marine sediments and hot springs. It may have a role in forest ecosystems and potential future applications as a biofertilizer and biocontrol agent in agriculture.
Pseudomonas flavescens is a Gram-negative bacterium that causes blight cankers on walnut trees. Based on 16S rRNA analysis, P. flavescens has been placed in the P. aeruginosa group.
Pseudomonas libanensis is a Gram-negative, rod-shaped, fluorescent, motile bacterium isolated from natural springs in Lebanon. Based on 16S rRNA analysis, P. libanensis has been placed in the P. fluorescens group.
Pseudomonas veronii is a Gram-negative, rod-shaped, fluorescent, motile bacterium isolated from natural springs in France. It may be used for bioremediation of contaminated soils, as it has been shown to degrade a variety of simple aromatic organic compounds. Based on 16S rRNA analysis, P. veronii has been placed in the P. fluorescens group.
Pseudomonas mosselii is a Gram-negative, rod-shaped, bacterium clinically isolated in France. Based on 16S rRNA analysis, P. mosselii has been placed in the P. putida group.
Pseudomonas plecoglossicida is a non-fluorescent, Gram-negative, rod-shaped, motile bacterium that causes hemorrhagic ascites in the ayu fish, from which it derives its name. Based on 16S rRNA analysis, P. plecoglossicida has been placed in the P. putida group.
Pseudomonas cedrina is a Gram-negative, rod-shaped bacterium isolated from spring waters in Lebanon. Based on 16S rRNA analysis, P. cedrina has been placed in the P. fluorescens group.
Pseudomonas lini is a fluorescent, Gram-negative, rod-shaped bacterium isolated from rhizospheric soil in France. The type strain is CFBP 5737, though there are also eight other strains known. This bacterium has also been isolated from endophytic tissues of lodgepole pine trees growing on gravel mining sites with potential to perform biological nitrogen fixation and plant growth promotion.
Pseudomonas gessardii is a fluorescent, Gram-negative, rod-shaped bacterium isolated from natural mineral waters in France. Based on 16S rRNA analysis, P. gessardii has been placed in the P. fluorescens group.
Pseudomonas rhodesiae is a Gram-negative, rod-shaped bacterium isolated from natural mineral waters. Based on 16S rRNA analysis, P. rhodesiae has been placed in the P. fluorescens group.
Pseudomonas azotoformans is a Gram-negative bacterium that infects cereal grains—especially rice. Based on 16S rRNA analysis, P. azotoformans has been placed in the P. fluorescens group.
Paraburkholderia phytofirmans is a species of proteobacteria. They have been reported to colonize endophytic tissues of hybrid spruce and lodgepole pine with a strong potential to perform biological nitrogen fixation and plant growth promotion.
Caballeronia sordidicola is a species of proteobacteria which has been reported to perform biological nitrogen fixation and promote plant growth
Caballeronia udeis is a bacterium from the genus Caballeronia and family Burkholderiaceae which has been reported to perform biological nitrogen fixation and promote plant growth
Paraburkholderia is a genus of Proteobacteria that are gram negative, slightly curved rods that are motile by means of flagella. They have been reported to colonize endophytic tissues of hybrid spruce and lodgepole pine with a strong potential to perform biological nitrogen fixation and plant growth promotion. Unlike Burkholderia species, Paraburkholderia members are not commonly associated with human infection. Paraburkholderia members form a monophyletic clade within the Burkholderiaceae family, which is what prompted their distinction as a genus independent from Burkholderia species, in combination with the finding of robust conserved signature indels which are unique to Paraburkholderia species, and are lacking in members of the genus Burkholderia. These CSIs distinguish the genus from all other bacteria. Additionally, the CSIs that were found to be shared by Burkholderia species are absent in Paraburkholderia, providing evidence of separate lineages.
Caballeronia is a genus of bacteria from the family of Burkholderiaceae which has been reported to perform biological nitrogen fixation and promote plant growth
