Stenotrophomonas rhizophila

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Classification

Domain: Bacteria

Phylum: Proteobacteria

Class: Gammaproteobacteria

Order: Xanthomonadales

Family: Xanthomonadaceae

Species

NCBI: Taxonomy

Stenotrophomonas rhizophila

Description and Significance

Describe the appearance, habitat, etc. of the organism, and why you think it is important.

Recent agricultural practices have resulted in salinized soils increasing the likelihood of plant life being affected by soil borne diseases. Fortunately the production of osmoprotective substances, trehalose and glucosylglycero, have allowed for plant-bacteria symbiotic relations to form and the cultivation of biofilms that allow plants to tolerate osmotic pressures. For example, in Uzbekistan’s highly salinized soils the presence of S. rhizophila dramatically increased plant growth by 180% [4].

Host dependent to where S. rhizophila's can be found, locations vary from stems, leaves, rhizosphere, or endophytes [5]. In tomatoes for instance, it is more common to find S. rhizophila's in its leaves whereas in cotton or sweet pepper plants will have a higher density in its rhizosphere and begin to deplete as you go up the plant [5]. For potato tubers, endophytic colonization was found to be more common.

Genome Structure

Stenotrophomonas rhizophila has a single circular genome with a length of 4,648,976 base pairs.[1] It shares a high degree of sequence similarity among members of the Stenotrophomonas genus. All members of the genus share genes for host invasion, antibiotic resistance, and anti-fungal properties. While these genes would normally be present in pathogens, S. rhizophila maintains non-pathogenicity due to its loss of virulence factors and heat shock factors. Instead, S. rhizophila maintains genes for spermidine, plant cell-wall degrading enzymes, and high salinity resistance. S. rhizophila also maintains a suite of genes needed for forming biofilms, such as flagella production, surface polysaccharides, and adhesion.[2]

Cell Structure, Metabolism and Life Cycle

Interesting features of cell structure; how it gains energy; what important molecules it produces.

S. rhizophila has important molecular products which help its symbiosis with plants. S. rhizophila produces spermidine which has been shown to increase plant growth as well as provide a molecular base for other polyamines that can protect against drought and salinity.[2] S. rhizophila also excretes glucosylglycerol(GG) and trehalose which have high water retaining capabilities into soil as salinity increases. This further increases plants' resistance to salinity as GG helps promote cell division and growth, despite conditions that would favor cell shrinkage.[3]

Ecology and Pathogenesis

Habitat; symbiosis; biogeochemical significance; contributions to environment.
If relevant, how does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

[1] NCBI "Stenotrophomonas rhizophila". NCBI Genome Assembly. 2013. Web. 21 Apr 2017.

[2] Alavi, P., Starcher, M., Thallinger, G., Zachow, C., Müller, H., and Berg, G. "Stenotrophomonas comparative genomics reveals genes and functions that differentiate beneficial and pathogenic bacteria." BMC Genomics. BioMed Central, 18 June 2014. Web. 21 Apr. 2017.

[3] Roder, A., Hoffmann, E., Hagemann, M., and Berg, G. "Synthesis of the compatible solutes glucosylglycerol and trehalose by salt-stressed cells of Stenotrophomonas strains." FEMS Microbiology Letters. Oxford University Press, 09 Jan. 2006. Web. 21 Apr. 2017.

[4] Alavi, P., Starcher, M., Zachow, C.S., Berg, G., and Müller, H. "Root-microbe systems: The effect and mode of interaction of Stress Protecting Agent (SPA) Stenotrophomonas rhizophila DSM14405T." Frontiers in Plant Science. Frontiers in Plant Science, 14 May 2013. Web. 21 Apr. 2017.

[5] Schmidt, C., Alavi, M., Cardinale, M., Müller, H., and Berg, G. "Stenotrophomonas rhizophila DSM14405T promotes plant growth probably by altering fungal communities in the rhizosphere." SpringerLink. Springer-Verlag, 03 May 2012. Web. 20 Apr. 2017.

[6] Ryan, R., Monchy, S., Cardinale, M., Taghavi, S., Crossman, L., Avison, M., Berg, G., Lelie, D., and Dow, J. "The versatility and adaptation of bacteria from the genus Stenotrophomonas." Nature Reviews Microbiology 7.7 (2009): 514-25. Web.

Author

Page authored by Esmeralda Martinez and Micah Maassen, students of Prof. Jay Lennon at Indiana University.