Xanthomonas campestris: Difference between revisions
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==Application to Biotechnology== | ==Application to Biotechnology== | ||
''X. campestris'' is used to create a stabilizing agent called xanthan gum. [1] It was first produced at Kelco Company, a major pharmaceutical company. This preservative is an ingredient in products like Kraft French dressing, Weight Watchers food, Wonder Bread products, and more. [6] Fermented from glucose by ''X. campestris'', xanthan gum is used to extend freshness for food products. In addition, xanthan gum also prolongs oil and gas wells even after production. Either pumped into the ground or using high pressure sandblasting, mixing water and xanthan gum into the wells will help release crude products of oil and cut through rocks in gas and oil wells. Xanthan gum costs $7 per pound compared to cornstarch for 89 cents per pound. [6] | |||
==Current Research== | ==Current Research== | ||
Revision as of 07:56, 27 August 2007
A Microbial Biorealm page on the genus Xanthomonas campestris
Classification
Higher order taxa
[Kingdom] Bacteria
[Phylum] Proteobacteria
[Class] Gamma Proteobacteria
[Order] Xanthomonadales
[Family] Xanthomonadaceae
[Genus] Xanthomonas
[Species] Xanthomonas campestris
Species
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NCBI: Taxonomy |
Xanthomonas campestris
Description and significance
Xanthomonas campestris is an aerobic, Gram-negative rod known to cause the black rot in crucifers by darkening the vascular tissues. Host associated, over 20 different pathovars of X. campestris have been identified by their distinctive pathogenicity on a wide range of plants including crops and wild plants. This bacteria is mesophilic with optimal temperature at 25-30 degrees Celsius (77-85 degrees Fahrenheit). It is inactive at temperatures below 10 degrees Celsius (50 degrees Fahrenheit) [10]. X. campestris have a long pili that helps them glide through water. They can live in a soil for over a year and spread through irrigation and surface water. Spraying healthy plants with copper fungicides may reduce the spread of the bacteria in the field. However, once the plant has been infected, X. campestris will eventually spread to the seed stalk inhibiting the growth of a healthy offspring.
By pure culture fermentation, X. campestris can produce an extracellular polysaccharide known as xanthan gum that is commerically manufactured as a stabilizing agent used in many industries. This organism is a model organism for plant pathogens to study their interaction between host. Due to the deficit in crops, further study of X. campestris’ genome may provide a solution to make plants resistant to this pathogen.
Genome structure
X. campestris have circular chromosomes containing at least two plasmids. The genome structures of X. campestris contain variation depending on the pathovars. However, the different strains of X. campestris exhibit similar characteristics like the mobile genetic elements and protein coding sequences. Over 4500 genes have been found in the genome to encode proteins however over one-third has no known function [11]. In X. campestris pv. campestris (Xcc) wild-type strain B100, it is found to contain a plasmid which contains 3-4 kb of chromosomal fragments [11]. With over 548 unique coding sequences, X. campestris pv. Vesicatoria (Xcv) is composed of a 5.17-Mb circular chromosome, four plasmids, and an essential type III protein secretion system for pathogenicity [3]. Using Recominbase-based In Vivo Expression Technology to target tomato, Xcv has been found to have 61 genes that are involved in the interaction between pathogen and host including a necessary virulence transporter, citH homologue gene [2].
Cell structure and metabolism
X. campestris is an aerobic, rod-shaped Gram-negative bacteria characterized by its two cell walls and yellow pigment. It has a filamentous structure of pili that provides motility in water, appendage to cell surface, and also a way to transfer bacterial proteins to the plant. Proteins found in X. campestris include XpsD protein which is required for extracellular protein secretion. X. campestris contains a type III secretion system (TTSS) that is necessary in order for this pathogen to attack the host. TTSS is important in pathogenesis because it delivers effector proteins into the host cell. These effectors may behave avirulently by disguising itself to secrete several hypersensitive reaction and outer proteins in order for interaction to occur with the host cells. [13] X. campestris is known to use cell-cell communication through diffusible signal factor (DSF) [4].
Ecology
Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.
Pathology
How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
Application to Biotechnology
X. campestris is used to create a stabilizing agent called xanthan gum. [1] It was first produced at Kelco Company, a major pharmaceutical company. This preservative is an ingredient in products like Kraft French dressing, Weight Watchers food, Wonder Bread products, and more. [6] Fermented from glucose by X. campestris, xanthan gum is used to extend freshness for food products. In addition, xanthan gum also prolongs oil and gas wells even after production. Either pumped into the ground or using high pressure sandblasting, mixing water and xanthan gum into the wells will help release crude products of oil and cut through rocks in gas and oil wells. Xanthan gum costs $7 per pound compared to cornstarch for 89 cents per pound. [6]
Current Research
Enter summaries of the most recent research here--at least three required
References
Edited by Tammie Chau, student of Rachel Larsen
