Difference between revisions of "Agrobacterium"

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<td bgcolor="#ffffff" height="874" valign="top" width="802"> <p><font size="+1"><b><a name="classif"></a>Classification</b></font><br>
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{{Curated}}
            <b>Higher order taxa:</b> Bacteria; Proteobacteria; Alphaproteobacteria; Rhizobiales; Rhizobiaceae; Rhizobium/Agrobacterium group <br>
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{{Biorealm Genus}}
            <b>Species: </b><em>Agrobacterium
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agile, Agrobacterium albertimagni, Agrobacterium aurantiacum,
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[[Image:Agro1.JPG|frame|''Agrobacterium'' ''tumefaciens'' cells attached to a plant cell. From [http://www.genomenewsnetwork.org/articles/12_01/A_tumefaciens_genome.shtml Genome News Network and Martha Hawes].]]
Agrobacterium larrymoorei, Agrobacterium radiobacter, Agrobacterium
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rhizogenes, Agrobacterium rubi, Agrobacterium tumefaciens,
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Agrobacterium vitis, Agrobacterium </em>sp.</p>
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{| width="800" cellspacing="2" cellpadding="2" align="center"
          <p><font size="+1"><b><a name="desc"></a>Description and Significance<br>
+
| width="802" height="874" bgcolor="#ffffff" valign="top" |
            </b></font>At the turn of the century <em>Agrobacterium tumefaciens</em>
+
<h2>Classification</h2><br style="clear:both" /><h3>'''Higher order taxa:'''</h3> Bacteria; Proteobacteria; Alphaproteobacteria; Rhizobiales; Rhizobiaceae; Rhizobium/Agrobacterium group <br /><h3>'''Species: '''</h3>''Agrobacterium agile, Agrobacterium albertimagni, Agrobacterium aurantiacum, Agrobacterium larrymoorei, Agrobacterium radiobacter, Agrobacterium rhizogenes, Agrobacterium rubi, Agrobacterium tumefaciens, Agrobacterium vitis, Agrobacterium ''sp.
was identified as the causal agent in crown gall disease in
+
 
dicotyledonous plants. Since then, thorough research has been done on
+
{|
this bacterium's mechanism of tumor induction; in addition, <em>Argorbacterium</em> is used in numerous research projects as a means with which to introduce new genes into the genomes of a number of plants. </p>
+
| height="10" bgcolor="#FFDF95" |
          <font size="+1"><b><a name="genome"></a>Genome Structure</b><font size="3"><br>
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'''NCBI: [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=357 Taxonomy] [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=genomeprj&cmd=Search&dopt=DocSum&term=txid357%5BOrganism:exp%5D Genomes]
              <em>Agrobacterium</em> <em>tumefaciens str. C58 </em>
+
|}
has an unusual chromosomal organization - it has a 2 Mb linear and a
+
 
2.8 Mb circular chromosome as well as a 206.479 kbp Ti (tumor-inducing)
+
<h2>Description and Significance<br /></h2>At the turn of the century ''Agrobacterium tumefaciens'' was identified as the causal agent in crown gall disease in dicotyledonous plants. Since then, thorough research has been done on this bacterium's mechanism of tumor induction; in addition, ''Argorbacterium'' is used in numerous research projects as a means with which to introduce new genes into the genomes of a number of plants.
plasmid. The genes that cause gall formation in plants are located for
+
<h2>Genome Structure</h2><br />''Agrobacterium'' ''tumefaciens str. C58 '' has an unusual chromosomal organization - it has a 2 Mb linear and a 2.8 Mb circular chromosome as well as a 206.479 kbp Ti (tumor-inducing) plasmid. The genes that cause gall formation in plants are located for the most part on the the Ti plasmid. Interestingly, if ''Agrobacterium'' is grown near its maximum temperature of about 30<sup>o</sup>C, then the plasmid is lost as well as the pathogenicity of the bacterium. The bacterium itself is still functional and can thrive in culture (Deacon).</font></font> The genome of ''Agrobacterium vitis'' is currnetly being sequenced. It causes gall disease in grapes.
the most part on the the Ti plasmid. Interestingly, if <em>Agrobacterium</em> is grown near its maximum temperature of about 30<sup>o</sup>C,
+
 
then the plasmid is lost as well as the pathogenicity of the bacterium.
+
<h2>Cell Structure and Metabolism</h2>
The bacterium itself is still functional and can thrive in culture
+
 
(Deacon).</font></font> The genome of <i>Agrobacterium vitis</i> is currnetly being sequenced. It causes gall disease in grapes.
+
{| width="802"
              <p> <font size="+1"><b><a name="cell"></a>Cell Structure and Metabolism</b></font></p>
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| width="792" height="156" |
          <table border="0" height="160" width="802">
+
''Agrobacterium'' ''tumefaciens'' is a Gram-negative, non-sporeforming, rod-shaped bacterium. ''Agrobacterium'' strains use different carbohydrates and are classified into three main biovars. The differences among biovars are mainly determined by the genes on the circular chromosome. ''A. tumefaciens ''is known for calling the formation of galls on plants that it infects. When a wound opens on the plant tissue, the motile cells of ''A. tumefaciens'' move into the tissue by chemotaxis as a response to the release of sugars and other components normally in the roots. While ''A''. ''tumefaciens'' cells without Ti plasmids recognize and move towards plant wounds, the strains containing the Ti plasmids respond even more strongly because they recognize phenolic compounds such as acetosyringone that come out of the wound (Deacon).
            <tbody><tr>
+
 
              <td height="156" width="792"><p><em>Agrobacterium</em> <em>tumefaciens</em> is a Gram-negative, non-sporeforming, rod-shaped bacterium. <em>Agrobacterium</em>
+
<h2>Ecology</h2>
strains use different carbohydrates and are classified into three main
+
 
biovars. The differences among biovars are mainly determined by the
+
''Agrobacterium'' ''tumefaciens'' can generally be found on and around root surfaces known as the rhizosphere. There it seems to use nutrients that leak from the root tissue. It will infect the tissue at wound sites formed from transplanting seedlings, burrowing animals or bugs, etc (Deacon). ''Agrobacterium'' ''radiobacter'' grows on various explosives such as nitroglycerine - they use this as their sole source of nitrogen. It removes two nitro groups from nitroglycerine by an NADH-dependent oxidoreductase, but can not use the carbon in nitroglycerine for growth because it cannot remove the third nitro group to release glycerol (White).
genes on the circular chromosome. <em>A. tumefaciens </em>is known for
+
 
calling the formation of galls on plants that it infects. When a wound
+
<h2>Crown Gall Disease</h2>
opens on the plant tissue, the motile cells of <em>A. tumefaciens</em> move into the tissue by chemotaxis as a response to the release of sugars and other components normally in the roots. While <em>A</em>. <em>tumefaciens</em>
+
 
cells without Ti plasmids recognize and move towards plant wounds, the
+
''Agrobacterium'' ''tumefaciens'' is most widely known for causing crown gall disease that affects many dicotyledonous (broad-leaved) plants; another strain called biovar 3 causes crown gall disease in grapvines. The disease causes the formation of tumor-like swellings called galls that can generally be found on the crown of the plant just above the soil. Crown gall disease does not usually seriously harm older plants; however, it may reduce the value of a plant in a nursery.
strains containing the Ti plasmids respond even more strongly because
+
[[Image:gall.jpg|frame|left|Courtesy of [http://biologi.uio.no/plfys/haa/gen/gmo.htm Halvor Aarnes
they recognize phenolic compounds such as acetosyringone that come out
+
A gall caused by ''Agrobacterium'' ''tumefaciens.'']]
of the wound (Deacon).</p>
+
''Agrobacterium'' ''tumefaciens'' causes crown gall disease by first transferring part of its DNA into an opening in the plant. The DNA is attches itself to the plants DNA through histones. The DNA then integrates itself into the plant's genome and causes the formation of the gall. Because of how smoothly ''Agrobacterium tumefaciens'' is able to transfer DNA it has become a helpful tool for scientists to use.
              </td>
+
 
            </tr>
+
<h2>Banana Vaccines </h2>
          </tbody></table>         
+
 
          <table border="0" height="521" width="797">
+
Bananas have potential to become the world's first edible vaccine due to ''Agrobacterium''. An edible vaccine doesn't need sterile syringes, costly refrigeration, or multiple injections. According to the World Health Organization (WHO), more than 2 million children die worldwide each year from diarrhea that can be prevented easily with vaccines.
            <tbody><tr>
+
[[Image:bananas.JPG|frame|left|From [http://www.wegmans.com/kitchen/ingredients/produce/fruit/bananas.asp Wegmans Bananas]]] Thus, researchers lead by Dr. Charles Arntzen are looking into making the food vaccines to prevent diarrhea caused by ''Escherichia coli'' and ''Vibrio cholara'' bacteria. First, the gene for an immune system-stimulating disease protein would have to be spliced into the bacterium. The bacterium is then allowed to contaminate banana cells, inserting the Ti plasmid (containing the spliced gene) into their chromosomes. The next step is to grow the cells until they are mature fruit-bearing plants. The fruits, when eaten, would transfer the immunity to a particular disease into the consumer's body. This would be a relatively inexpensive and feasible method to distribute certain vaccines to people, especially in developing countries.
              <td height="517" valign="top" width="441"><div align="left">
+
 
                <p><font size="+1"><b><a name="eco"></a>Ecology</b></font></p>
+
 
                </div>
+
This has already been shown to work using potatoes and a modified'' E. coli'' protein that is known to cause severe diarrhea. When mice ate the raw engineered potatoes, they developed the antibodies to the ''E. coli ''toxin. Clinical tests on humans eating genetically engineered potatoes also showed that they started producing antibodies against Norwalk virus, which causes acute bouts of diarrhea (Redig 2003). For now, all clinical trials involve genetically modified potatoes or tomatoes, both of which can easily be freeze-dried, transported, and reconstituted. These can be more easily dosage regulated and quality controlled, unlike a banana tree growing in the middle of a village, for example. But the ideal of fresh banana vaccines is still being developed and perfected.
                <p align="left"><em>Agrobacterium</em> <em>tumefaciens</em>
+
 
can generally be found on and around root surfaces known as the
+
<h2>References</h2>
rhizosphere. There it seems to use nutrients that leak from the root
+
 
tissue. It will infect the tissue at wound sites formed from
+
[http://www.wegmans.com/kitchen/ingredients/produce/fruit/bananas.asp Brown, Kathryn. 1996. "Vaccine Cuisine." Environmental Health Perspectives, vol. 104, no. 3. ]
transplanting seedlings, burrowing animals or bugs, etc (Deacon). <em>Agrobacterium</em> <em>radiobacter</em>
+
 
grows on various explosives such as nitroglycerine - they use this as
+
[http://helios.bto.ed.ac.uk/bto/microbes/crown.htm Deacon, Jim. The University of Edinburgh: The Microbial World: Biology and Control of Crown Gall (''Agrobacterium tumfaciens'').]
their sole source of nitrogen. It removes two nitro groups from
+
 
nitroglycerine by an NADH-dependent oxidoreductase, but can not use the
+
[http://www.plantphysiol.org/cgi/content/full/138/3/1318 Abraham Loyter][http://www.plantphysiol.org/cgi/content/full/138/3/1318 , Joseph Rosenbluh, Nehama Zakai, Jianxiong Li, Stanislav V. Kozlovsky, Tzvi Tzfira and Vitaly Citovsky. The Plant VirE2 Interacting Protein 1. A Molecular Link between the Agrobacterium T-Complex and the Host Cell Chrom<font size="3">atin?''Plant Physiology'', July 2005, Vol. 138, pp. 1318-1321.</font>]
carbon in nitroglycerine for growth because it cannot remove the third
+
 
nitro group to release glycerol (White).</p>               
+
[http://www.jyi.org/volumes/volume7/issue1/features/Redig_bananas.pdf Redig, Mandy. 2003. "Banana vaccines: A conversation with Dr. Charles Arntzen." Journal of Young Investigators, vol. 7, no. 1. ]
                <p align="left"><strong><font size="+1"><a name="gall"></a>Crown Gall Disease</font></strong></p>
+
 
                <p align="left"><em>Agrobacterium</em> <em>tumefaciens</em>
+
[http://www.cf.ac.uk/biosi/research/molecular/staff/gfw.html White, Graham. The Molecular Cell Biology Research Group: Research ]
is most widely known for causing crown gall disease that affects many
+
|}
dicotyledonous (broad-leaved) plants; another strain called biovar 3
 
causes crown gall disease in grapvines. The disease causes the
 
formation of tumor-like swellings called galls that can generally be
 
found on the crown of the plant just above the soil. Crown gall disease
 
does not usually seriously harm older plants; however, it may reduce
 
the value of a plant in a nursery.</p>
 
              <p align="left"><em>Agrobacterium</em> <em>tumefaciens</em>
 
causes crown gall disease by first transferring part of its DNA into an
 
opening in the plant. The DNA is attches itself to the plants DNA
 
through histones. The DNA then integrates itself into the plant's
 
genome and causes the formation of the gall. Because of how smoothly <em>Agrobacterium tumefaciens</em> is able to transfer DNA it has become a helpful tool for scientists to use. </p></td>
 
              <td width="341"><p align="center"><img src="Agrobacterium_files/gall.jpg" alt="gall caused by agrobacterium tumefaciens" height="345" width="275"></p>
 
              <p align="center">A gall caused by <em>Agrobacterium</em> <em>tumefaciens</em>. Courtesy of <a href="http://biologi.uio.no/plfys/haa/gen/gmo.htm">Halvor Aarnes</a>.</p></td>
 
            </tr>
 
          </tbody></table>         
 
          <p><strong><font size="+1"><a name="banana"></a>Banana Vaccines </font></strong></p>
 
          <table border="0" width="792">
 
            <tbody><tr>
 
              <td height="287" valign="top" width="332"><p align="center"><img src="Agrobacterium_files/bananas.JPG" alt="bananas" height="257" width="321"></p>
 
              <p align="center">Bananas. From <a href="http://www.wegmans.com/kitchen/ingredients/produce/fruit/bananas.asp">Wegmans</a>. </p></td>
 
              <td width="450"><p align="left">Bananas have potential to become the world's first edible vaccine due to <em>Agrobacterium</em>.
 
An edible vaccine doesn't need sterile syringes, costly refrigeration,
 
or multiple injections. According to the World Health Organization
 
(WHO), more than 2 million children die worldwide each year from
 
diarrhea that can be prevented easily with vaccines. Thus, researchers
 
lead by Dr. Charles Arntzen are looking into making the food vaccines
 
to prevent diarrhea caused by <em>Escherichia coli</em> and <em>Vibrio cholara</em>
 
bacteria. First, the gene for an immune system-stimulating disease
 
protein would have to be spliced into the bacterium. The bacterium is
 
then allowed to contaminate banana cells, inserting the Ti plasmid
 
(containing the spliced gene) into their chromosomes. The next step is
 
to grow the cells until they are mature fruit-bearing plants. The
 
fruits, when eaten, would transfer the immunity to a particular disease
 
into the consumer's body. This would be a relatively inexpensive and
 
feasible method to distribute certain vaccines to people, especially in
 
developing countries.</p>
 
              </td>
 
            </tr>
 
          </tbody></table>         
 
          <p align="left">This has already been shown to work using potatoes and a modified<em> E. coli</em>
 
protein that is known to cause severe diarrhea. When mice ate the raw
 
engineered potatoes, they developed the antibodies to the <em>E. coli </em>toxin.
 
Clinical tests on humans eating genetically engineered potatoes also
 
showed that they started producing antibodies against Norwalk virus,
 
which causes acute bouts of diarrhea (Redig 2003). For now, all
 
clinical trials involve genetically modified potatoes or tomatoes, both
 
of which can easily be freeze-dried, transported, and reconstituted.
 
These can be more easily dosage regulated and quality controlled,
 
unlike a banana tree growing in the middle of a village, for example.
 
But the ideal of fresh banana vaccines is still being developed and
 
perfected. </p>
 

Latest revision as of 21:40, 23 July 2010

This is a curated page. Report corrections to Microbewiki.

A Microbial Biorealm page on the genus Agrobacterium

Agrobacterium tumefaciens cells attached to a plant cell. From Genome News Network and Martha Hawes.


Classification


Higher order taxa:

Bacteria; Proteobacteria; Alphaproteobacteria; Rhizobiales; Rhizobiaceae; Rhizobium/Agrobacterium group

Species:

Agrobacterium agile, Agrobacterium albertimagni, Agrobacterium aurantiacum, Agrobacterium larrymoorei, Agrobacterium radiobacter, Agrobacterium rhizogenes, Agrobacterium rubi, Agrobacterium tumefaciens, Agrobacterium vitis, Agrobacterium sp.

NCBI: Taxonomy Genomes

Description and Significance

At the turn of the century Agrobacterium tumefaciens was identified as the causal agent in crown gall disease in dicotyledonous plants. Since then, thorough research has been done on this bacterium's mechanism of tumor induction; in addition, Argorbacterium is used in numerous research projects as a means with which to introduce new genes into the genomes of a number of plants.

Genome Structure


Agrobacterium tumefaciens str. C58 has an unusual chromosomal organization - it has a 2 Mb linear and a 2.8 Mb circular chromosome as well as a 206.479 kbp Ti (tumor-inducing) plasmid. The genes that cause gall formation in plants are located for the most part on the the Ti plasmid. Interestingly, if Agrobacterium is grown near its maximum temperature of about 30oC, then the plasmid is lost as well as the pathogenicity of the bacterium. The bacterium itself is still functional and can thrive in culture (Deacon). The genome of Agrobacterium vitis is currnetly being sequenced. It causes gall disease in grapes.

Cell Structure and Metabolism

Agrobacterium tumefaciens is a Gram-negative, non-sporeforming, rod-shaped bacterium. Agrobacterium strains use different carbohydrates and are classified into three main biovars. The differences among biovars are mainly determined by the genes on the circular chromosome. A. tumefaciens is known for calling the formation of galls on plants that it infects. When a wound opens on the plant tissue, the motile cells of A. tumefaciens move into the tissue by chemotaxis as a response to the release of sugars and other components normally in the roots. While A. tumefaciens cells without Ti plasmids recognize and move towards plant wounds, the strains containing the Ti plasmids respond even more strongly because they recognize phenolic compounds such as acetosyringone that come out of the wound (Deacon).

Ecology

Agrobacterium tumefaciens can generally be found on and around root surfaces known as the rhizosphere. There it seems to use nutrients that leak from the root tissue. It will infect the tissue at wound sites formed from transplanting seedlings, burrowing animals or bugs, etc (Deacon). Agrobacterium radiobacter grows on various explosives such as nitroglycerine - they use this as their sole source of nitrogen. It removes two nitro groups from nitroglycerine by an NADH-dependent oxidoreductase, but can not use the carbon in nitroglycerine for growth because it cannot remove the third nitro group to release glycerol (White).

Crown Gall Disease

Agrobacterium tumefaciens is most widely known for causing crown gall disease that affects many dicotyledonous (broad-leaved) plants; another strain called biovar 3 causes crown gall disease in grapvines. The disease causes the formation of tumor-like swellings called galls that can generally be found on the crown of the plant just above the soil. Crown gall disease does not usually seriously harm older plants; however, it may reduce the value of a plant in a nursery.

Courtesy of [http://biologi.uio.no/plfys/haa/gen/gmo.htm Halvor Aarnes A gall caused by Agrobacterium tumefaciens.

Agrobacterium tumefaciens causes crown gall disease by first transferring part of its DNA into an opening in the plant. The DNA is attches itself to the plants DNA through histones. The DNA then integrates itself into the plant's genome and causes the formation of the gall. Because of how smoothly Agrobacterium tumefaciens is able to transfer DNA it has become a helpful tool for scientists to use.

Banana Vaccines

Bananas have potential to become the world's first edible vaccine due to Agrobacterium. An edible vaccine doesn't need sterile syringes, costly refrigeration, or multiple injections. According to the World Health Organization (WHO), more than 2 million children die worldwide each year from diarrhea that can be prevented easily with vaccines.

Thus, researchers lead by Dr. Charles Arntzen are looking into making the food vaccines to prevent diarrhea caused by Escherichia coli and Vibrio cholara bacteria. First, the gene for an immune system-stimulating disease protein would have to be spliced into the bacterium. The bacterium is then allowed to contaminate banana cells, inserting the Ti plasmid (containing the spliced gene) into their chromosomes. The next step is to grow the cells until they are mature fruit-bearing plants. The fruits, when eaten, would transfer the immunity to a particular disease into the consumer's body. This would be a relatively inexpensive and feasible method to distribute certain vaccines to people, especially in developing countries.


This has already been shown to work using potatoes and a modified E. coli protein that is known to cause severe diarrhea. When mice ate the raw engineered potatoes, they developed the antibodies to the E. coli toxin. Clinical tests on humans eating genetically engineered potatoes also showed that they started producing antibodies against Norwalk virus, which causes acute bouts of diarrhea (Redig 2003). For now, all clinical trials involve genetically modified potatoes or tomatoes, both of which can easily be freeze-dried, transported, and reconstituted. These can be more easily dosage regulated and quality controlled, unlike a banana tree growing in the middle of a village, for example. But the ideal of fresh banana vaccines is still being developed and perfected.

References

Brown, Kathryn. 1996. "Vaccine Cuisine." Environmental Health Perspectives, vol. 104, no. 3.

Deacon, Jim. The University of Edinburgh: The Microbial World: Biology and Control of Crown Gall (Agrobacterium tumfaciens).

Abraham Loyter, Joseph Rosenbluh, Nehama Zakai, Jianxiong Li, Stanislav V. Kozlovsky, Tzvi Tzfira and Vitaly Citovsky. The Plant VirE2 Interacting Protein 1. A Molecular Link between the Agrobacterium T-Complex and the Host Cell Chromatin?Plant Physiology, July 2005, Vol. 138, pp. 1318-1321.

Redig, Mandy. 2003. "Banana vaccines: A conversation with Dr. Charles Arntzen." Journal of Young Investigators, vol. 7, no. 1.

White, Graham. The Molecular Cell Biology Research Group: Research