Pseudomonas oryzihabitans

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1. Classification

a. Higher order taxa

Domain: Bacteria Phylum: Proteobacteria Class: Gammaproteobacteria Order: Pseudomonadales Family: Pseudomonadaceae Genus: Pseudomonas Species: Pseudomonas oryzihabitans

2. Introduction

Pseudomonas oryzihabitans is a rod-shaped, Gram-negative bacterium known to cause infections in humans, in both immunocompromised and non-immunocompromised individuals. Some infections that P. oryzihabitans can cause include nosocomial (hospital-acquired) sepsis, bacteremia, endophthalmitis, and peritonitis (1). In other unique cases, P. oryzihabitans has been documented to cause urinary tract infections and green nail syndrome (2, 3). P. oryzihabitans is commonly found in hospital settings, on respiratory equipment and unsterilized medical tools (1). In nature, P. oryzihabitans can be found in moist environments, like soil, rice paddies, running or standing water, and groundwater (4,5). In these environments, P. oryzihabitans has potential to promote root growth via suppressing parasitic nematode populations, making it easier to grow and maintain certain crops (6). Additionally, P. oryzihabitans has a positive growth effect on members of the cucurbit family affected by Bacterial Fruit Blotch disease (BFB) (7). P. oryzihabitans also negatively impacts the growth of Muskmelon by causing stem and leaf rot (8). Overall, in this paper we discuss how P. oryzihabitans is a multifaceted organism that plays various roles ecologically, agriculturally, and medically that has not been compiled previously.

3. Genome structure

The genome of two strains of Pseudomonas oryzihabitans, AXSa06 and AXSa07, have been sequenced (9). The genome of the P. oryzihabitans strain AXSa06 has 5,109,344 base pairs in total and the AXSa07 strain has 4,666,115 base pairs. The two strains share a similar % G+C content, both around 66% of the whole genome (9). In the AXSa07 strain genome, there are 4495 protein coding sequences. However, the AXSa07 strain has 15 rRNA genes, higher than the AXSa06 strain, which has 5 rRNA genes (9). A key difference between the AXSa06 strain and the AXSa07 strain lies in their ACC deaminase activity. ACC deaminase activity is often used by soil microorganisms to enhance plant growth by inhibiting the enzyme 1-aminocyclopropane-1-carboxylic acid (ACC), which is a precursor to ethylene, a hormone that controls plant maturation. The P. oryzihabitans strain AXSa06 has genes coding for ACC deaminase activity, while AXSa07 strain does not (9). In the P. oryzihabitans strain AXSa06 genome, there are 4929 protein coding sequences (9). Besides AXSa06 and AXSa07 strains, the genome of GCMCC 6169, a soil strain of P. oryzihabitans, was shown to encode the protein POEP1 which aids cellulose breakdown. Although POEP1 does not break down cellulose directly, it synergistically enhances the activity of cellulase, a protein that directly hydrolyzes cellulose for energy (10).

4. Cell structure

Pseudomonas oryzihabitans is a rod-shaped, Gram-negative bacteria that forms yellow-color colonies with a rough or wrinkled appearance (9). Since P. oryzihabitans is a Gram-negative bacteria, this means that it has a thin peptidoglycan cell wall with porins that allow substance passage and lipopolysaccharides that may cause toxicity to an infected host. The yellow pigmentation is not dissolvable in water (11). In addition, P. oryzihabitans is non-endospore forming (11). P. oryzihabitans bacterium is motile via one or more polar flagella (11).

5. Metabolic processes

P. oryzihabitans optimal growth conditions are 37℃, 7.5 pH (11). P. oryzihabitans does not ferment and cannot break down glucose (6). This bacterium can also break down 2,4-DNT, a common soil contaminant, (11). When an oxidase test was performed on the bacterium, P. oryzihabitans tested oxidase positive (12). The top two carbon sources for P. oryzihabitans are listed respectively: Lactose and Succinate all at 0.2%. The top three nitrogen sources for the bacterium’s growth yeast, casein, and KNO3 (12). A particular strain of P. oryzihabitans,PGP01, can achieve optimal growth by utilizing carbon and nitrogen sources from agro-food waste. Since P. oryzihabitans can have a positive relationship with plant roots, plant and food waste were used as nutrient sources (13). Frozen potato peel and pulp medium (FPP), tryptone (10 g/L), sugar cane molasses (10 g/L), along with NaCl (5 g/L) and K2HPO4 (2.5 g/L) were combined for optimal growth of P. oryzihabitans. The study demonstrated the potential of P. oryzihabitans in re-purposing and diminishing food waste using its metabolic processes (13). Metabolic ability for chemical substances in P. oryzihabitans can differ from other members of the Pseudomonas genus and within separate strains of P. oryzihabitans species. Two strains (NT0-1 and NT0-6) of P. oryzihabitans in particular have different H2O2 metabolism abilities in seedlings (14). Compared to the Pseudomonas fluorescens strains NT0-2 and NT0-8, which did not produce a level of H2O2 above detection, both P. oryzihabitans strains produce measurable amounts of H2O2 and have a 3.6 time decrease in H2O2 after 1.5 hours of inoculation. However, H2O2 concentration generated by P. oryzihabitans NT0-1 was 3.2 times higher than that of the NT0-6 strain, and the decrease in H2O2 metabolic concentration followed an initial increase (14). Other strains of P. oryzihabitans, such as the GCMCC 6169 strain, have a genome that encodes for the protein POEP1. When incubated together, POEP1 and cellulase produced a maximum cellulose breakdown amount of 4.2mg, while cellulase alone only hydrolyzed 2.00mg of cellulose after a 48 hour period (10). Furthermore, L-Asparaginase, a protein that catalyzes the production of aspartic acid and ammonia from the amino acid asparagine, was found in an endophytic strain of P. oryzihabitans isolated from Hibiscus rosa-sinensis (Shoeblack plant)(15). The endosymbiont P. oryzihabitans strain exhibited high L-Asparaginase activity (4.3 U/mL) under optimized growth environments. L-Asparaginase has crucial therapeutic value and effectively treats acute lymphocytic leukemia (ALL)(15).

6. Ecology

Habitat; symbiosis; contributions to the environment.

7. Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

8. Current Research

Include information about how this microbe (or related microbes) are currently being studied and for what purpose

9. References

It is required that you add at least five primary research articles (in same format as the sample reference below) that corresponds to the info that you added to this page. [Sample reference] Faller, A., and Schleifer, K. "Modified Oxidase and Benzidine Tests for Separation of Staphylococci from Micrococci". Journal of Clinical Microbiology. 1981. Volume 13. p. 1031-1035.