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Influence du tryptophane sur le pouvoir pathogène de Streptomyces scabiei, l'agent causal de la gale commune de la pomme de terre
| Content Provider | Semantic Scholar |
|---|---|
| Author | Legault, Geneviève |
| Copyright Year | 2010 |
| Abstract | Streptomyces scabiei is the causal agent of potato common scab but the bacterium is also known for its ability to inhibit the growth of most monocot and dicot seedlings. The virulence of this phytopathogenic agent mainly depends upon the production of a toxin called thaxtomin A. S. scabiei also produces the plant growth hormone auxin [indole-3-acetic acid (IAA)] but the role of this hormone in the interaction between pathogenic stretomycetes and plants has not been elucidated yet. Tryptophan is a biosynthetic precursor of both auxin and thaxtomin A. While the in vitro auxin production by S. scabiei depended mostly on the availability of tryptophan, addition of this amino acid to a culture medium inhibited the biosynthesis of thaxtomin A. Expression of thaxtomin A biosynthetic genes nos and txtA were strongly repressed in the presence of tryptophan, however no modulation of the expression was observed for IAA biosynthetic genes iaaM and iaaH. The effect of an exogenous supply of tryptophan on S. scabiei virulence was assessed on radish seedlings grown under gnotobiotic conditions. Addition of tryptophan reduced symptoms of infected radish roots when compared to seedlings grown in the absence of the bacterium, at the same tryptophan concentration. S. scabiei even acted as a plant growth promoting bacterium at high tryptophan concentrations. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://savoirs.usherbrooke.ca/bitstream/handle/11143/4877/MR70740.pdf?isAllowed=y&sequence=1 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
