More than one way to bug a plant: Rhodococcus fascians infects plants and is one cause of the condition known as witches' broom. New results implicate an unusual linear plasmid in production of this complex disease phenotype
A common environmental condition that plants encounter is contact with bacteria. A variety of bacteria-plant interactions lead to alterations in normal plant processes and development. Alteration of normal plant growth also occurs with infection by Rhodococcus fascians, a Gram positive phytopathogen...
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Veröffentlicht in: | Current biology 1992-01, Vol.2 (7), p.387-388 |
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Sprache: | eng |
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Zusammenfassung: | A common environmental condition that plants encounter is contact with bacteria. A variety of bacteria-plant interactions lead to alterations in normal plant processes and development. Alteration of normal plant growth also occurs with infection by Rhodococcus fascians, a Gram positive phytopathogen evolutionarily distinct from the Gram negative pathogens Agrobacterium and Pseudomonas. Rhodococcus fascians (also known as Corynebacterium fascians) causes fasciation disease in many types of dicotyledonous and monocotyledonous plants, characterized by loss of apical dominance and outgrowth of lateral buds, producing leafy galls. Extreme cases of fasciation in dicotyledons results in a condition termed witches' broom, a multitude of lateral buds growing close together. Early experiments duplicated the symptoms of fasciation by treating seeds or seedlings with continual application of increased levels of cytokinins. Although the production and release of cytokinins by R. fascians was quickly detected, the location of the responsible genes has been elusive. In the R. fascians strain studied by Crespi et al., the essential fasciation genes were found not on a circular plasmid, as seen in the Gram negative phytopathogenic bacterial systems such as Agrobacterium , but on a large (200 kb) conjugative linear plasmid, pFiD188. Analysis of other R. fascians strains showed that the presence of similarly sized linear plasmids correlates with virulence. |
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ISSN: | 0960-9822 |