Molecular Plant Pathology - Pathogen Profiles
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From host recognition to T-DNA integration: the
function of bacterial and plant genes in the Agrobacterium–plant cell
interaction]
Tzvi Tzfira and Vitaly Citovsky
Department of Biochemistry and Cell Biology, State University of
New York, Stony Brook, NY 11794-5215, USA
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| Summary: |
Agrobacterium tumefaciens and its related species, A.
rhizogenes and A. vitis, are the only known bacterial pathogens
which ‘genetically invade’ host plants and stably integrate part of
their genetic material into the host cell genome. Thus, A. tumefaciens
has evolved as a major tool for plant genetic engineering. Further-more,
this unique process of interkingdom DNA transfer has been utilized as a
model system for studies of its underlying biological events, such as
intercellular signalling, cell-to-cell DNA transport, protein and DNA
nuclear import and integration. To date, numerous bacterial proteins and
several plant proteins have been implicated in the A. tumefaciens–plant
cell interaction. Here, we discuss the molecular interactions among these
bacterial and plant factors and their role in the A. tumefaciens–plant
cell DNA transfer. |
| Taxonomic relationship: |
Bacteria; Proteobacteria; alpha subdivision; Rhizobiaceae
group; Rhizobiaceae family; Agrobacterium genus. |
| Microbiological properties: |
Gram-negative, nonsporing, motile, rod-shaped,
soil-borne. |
| Related species: |
A. rhizogenes (causes root formation in infected
plants), A. vitis (causes gall formation on grapevines). |
| Disease symptoms: |
Formation of neoplastic swellings (galls) on plant roots,
crowns, trunks and canes. Galls interfere with water and nutrient flow in
the plants, and seriously infected plants suffer from weak, stunted growth
and low productivity. |
| Host range: |
One of the widest host ranges known among plant pathogens;
can potentially attack all dicotyledonous plant species. Also, under
controlled conditions (usually in tissue culture), can infect, albeit with
lower efficiency, several monocotyledonous species. |
| Agronomic importance: |
The disease currently affects plants belonging to the rose
family, e.g. apple, pear, peach, cherry, almond, roses, as well as poplar
trees (aspen). |
| Useful web site: |
http://www.bio.purdue.edu/courses/gelvinweb/gelvin.html |
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Agrobacterium tumefaciens, bacterium and disease. Scanning electron
micrograph of wild-type A. tumefaciens cells colonizing aspen roots
bar = 80 mm (left); Crown gall formation on a stem of a tomato plant
infected with wild-type A. tumefaciens (right)
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