Abstract
Trichoderma species and fluorescent Pseudomonas spp. have been reported to induce systemic resistance in plants.
In this study the effectiveness of a combination of these biological control agents on the efficacy of induced resistance
was investigated in cucumber and the model plant Arabidopsis thaliana. Trichoderma harzianum Tr6, and
Pseudomonas sp. Ps14, both isolated from the rhizosphere of cucumber, were tested as a single application and
in combination for their abilities to elicit induced resistance in cucumber against Fusariumoxysporum f. sp. radicis
cucumerinum and in A. thaliana against Botrytis cinerea. The combination of Tr6 and Ps14 induced a significantly
higher level of resistance incucumber,whichwas associatedwiththe primedexpression of a set of defense-related
genes upon challenge with Fusarium. In Arabidopsis both Ps14 and Tr6 triggered ISR against B. cinerea but their
combination did not show enhanced effects. In the induced systemic resistance-defective Arabidopsis mutant
myb72, none of the treatments protected against B. cinerea,whereas in the SA-impaired mutant sid2 all treatments
were effective. Taken together, these results indicate that in Arabidopsis Ps14 and Tr6 activate the same signaling
pathway and thus have no enhanced effect in combination. The enhanced protection in cucumber by the combination
is most likely due to activation of different signaling pathways by the two biocontrol agents.
In this study the effectiveness of a combination of these biological control agents on the efficacy of induced resistance
was investigated in cucumber and the model plant Arabidopsis thaliana. Trichoderma harzianum Tr6, and
Pseudomonas sp. Ps14, both isolated from the rhizosphere of cucumber, were tested as a single application and
in combination for their abilities to elicit induced resistance in cucumber against Fusariumoxysporum f. sp. radicis
cucumerinum and in A. thaliana against Botrytis cinerea. The combination of Tr6 and Ps14 induced a significantly
higher level of resistance incucumber,whichwas associatedwiththe primedexpression of a set of defense-related
genes upon challenge with Fusarium. In Arabidopsis both Ps14 and Tr6 triggered ISR against B. cinerea but their
combination did not show enhanced effects. In the induced systemic resistance-defective Arabidopsis mutant
myb72, none of the treatments protected against B. cinerea,whereas in the SA-impaired mutant sid2 all treatments
were effective. Taken together, these results indicate that in Arabidopsis Ps14 and Tr6 activate the same signaling
pathway and thus have no enhanced effect in combination. The enhanced protection in cucumber by the combination
is most likely due to activation of different signaling pathways by the two biocontrol agents.
| Original language | English |
|---|---|
| Pages (from-to) | 14-23 |
| Number of pages | 10 |
| Journal | Biological Control |
| Volume | 65 |
| DOIs | |
| Publication status | Published - 2013 |
Keywords
- Arabidopsis thaliana
- Botrytis cinerea
- Cucumber
- Defense genes
- Fusarium oxysporum f. sp. radicis cucumerinum
- Induced systemic resistance
- Pseudomonas
- Trichoderma