Pseudonocardia sp.

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Classification

Members of the Pseudonocardia genus are classified as such:

Domain Bacteria

Phylum Actinomycetota

Class Actinomycetia

Order Pseudonocardiales

Family Pseudonocardiaceae

Genus Pseudonocardia

Species

This page covers details about the general genus of Pseudonocardia sp. There are currently 53 members of the Pseudonocardia genus.

Description and Significance

Describe the appearance, habitat, etc. of the organism, and why you think it is important. Pseudonocardia are Gram-positive bacteria, meaning they have only one cell membrane and a very thick peptidoglycan cell wall. They are non-motile bacteria, meaning they are unable to move independently in their environments. They are also aerobic bacteria, meaning they use oxygen as a terminal electron acceptor in metabolic pathways. They are rod-shaped and often grow in a branching pattern.

Many specific Pseudonocardia species have been isolated from soils, trees, and plant roots from China and Australia, highlighting their importance as environmental bacteria. However, they can also be found in aquatic ecosystems. Pseudonardia are known as "free-living," meaning they are not dependent on another organism for survival. That being said, Pseudonocardia species often are part of very significant symbiotic relationships

Attine ants are fungus-growing, leaf-cutting ants. Such ants have their own symbiotic relationships with fungi. These ants grow fungi underground, which they can then eat. In turn, the fungus relies on the ants for its vertical transmission. These fungi are incapable of reproducing sexually using spores, and so ant queens take a piece of the fungal colony with them when they go to establish a new colony, thus propagating the fungus. However, this symbiotic relationship is susceptible to disruption via infection by other fungal species like Escovopsis. This fungus can be extremely pathogenic toward the fungus the ants grow. At the same time that this fungus was discovered, a bacterial symbiont was discovered in the ant that produces compounds that fight infection by organisms like Escovopsis. This bacterium is Pseudonocardia. Compounds naturally produced by Pseudonocardia are used to protect both the ants and their fungi from infection. These compounds have both antibiotic (bacteria-killing) and antifungal (fungus-killing) properties. Thus, ants having a symbiotic relationship with Pseudonocardia protects their own symbiotic relationship with the fungi from disruption by infection.

Genome Structure

Pseudonocardia sp. have one circular chromosome about six million base-pairs (~6,135 kbp, ~6.1 mbp) in length. Pseudonocardia sp. also often have two extrachromosomal plasmids, named pFRP1-1 and pFRP1-2. Both of these plasmids are circular as well. Both are significantly smaller than the genome; pFRP1-1 is about 297 kbp in length while pFRP1-2 is about half of that size, at 121 kbp in length. All in all, the genetic material housed by Pseudonocardia sp. cells code for 5,109 proteins and 63 RNAs. However, because these bacteria live in the soil, they are difficult to isolate and thus there are only about 20 genome sequences currently available for the entire genus, which houses 53 species.

Cell Structure, Metabolism and Life Cycle

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

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

Pseudonocardia https://en.wikipedia.org/wiki/Pseudonocardia

Pseudonocardia acaciae https://en.wikipedia.org/wiki/Pseudonocardia_acaciae

Pseudonocardia sp. EC080625-04 https://www.genome.jp/kegg-bin/show_organism?org=psee

Genome Analysis of Two Pseudonocardia Phylotypes Associated with Acromyrmex Leafcutter Ants Reveals Their Biosynthetic Potential https://www.frontiersin.org/articles/10.3389/fmicb.2016.02073/full

Author

Page authored by Caleb Hill, Sannnoong Hu, and Abby Jackson, students of Prof. Jay Lennon at Indiana University.