Abstract
Salicylic acid (SA), jasmonic acid (JA), and ethylene (ET)
are each involved in the regulation of basal resistance
against different pathogens. These three signals play important roles in induced resistance as well. SA is a key
regulator of pathogen-induced systemic acquired resistance
(SAR), whereas JA and ET are required for rhizobacteriamediated induced systemic resistance (ISR). Both types of
induced resistance are effective against a broad spectrum
of pathogens. In this study, we compared the spectrum of
effectiveness of SAR and ISR using an oomycete, a fungal,
a bacterial, and a viral pathogen. In noninduced Arabidopsis plants, these pathogens are primarily resisted through
either SA-dependent basal resistance (Peronospora parasitica and Turnip crinkle virus [TCV]), JA/ET-dependent
basal resistance responses (Alternaria brassicicola), or a
combination of SA-, JA-, and ET-dependent defenses (Xanthomonas campestris pv. armoraciae). Activation of ISR resulted in a significant level of protection against A. brassicicola, whereas SAR was ineffective against this pathogen.
Conversely, activation of SAR resulted in a high level of
protection against P. parasitica and TCV, whereas ISR conferred only weak and no protection against P. parasitica
and TCV, respectively. Induction of SAR and ISR was
equally effective against X. campestris pv. armoraciae.
These results indicate that SAR is effective against pathogens that in noninduced plants are resisted through SAdependent defenses, whereas ISR is effective against pathogens that in noninduced plants are resisted through JA/ETdependent defenses. This suggests that SAR and ISR constitute a reinforcement of extant SA- or JA/ET-dependent
basal defense responses, respectively.
are each involved in the regulation of basal resistance
against different pathogens. These three signals play important roles in induced resistance as well. SA is a key
regulator of pathogen-induced systemic acquired resistance
(SAR), whereas JA and ET are required for rhizobacteriamediated induced systemic resistance (ISR). Both types of
induced resistance are effective against a broad spectrum
of pathogens. In this study, we compared the spectrum of
effectiveness of SAR and ISR using an oomycete, a fungal,
a bacterial, and a viral pathogen. In noninduced Arabidopsis plants, these pathogens are primarily resisted through
either SA-dependent basal resistance (Peronospora parasitica and Turnip crinkle virus [TCV]), JA/ET-dependent
basal resistance responses (Alternaria brassicicola), or a
combination of SA-, JA-, and ET-dependent defenses (Xanthomonas campestris pv. armoraciae). Activation of ISR resulted in a significant level of protection against A. brassicicola, whereas SAR was ineffective against this pathogen.
Conversely, activation of SAR resulted in a high level of
protection against P. parasitica and TCV, whereas ISR conferred only weak and no protection against P. parasitica
and TCV, respectively. Induction of SAR and ISR was
equally effective against X. campestris pv. armoraciae.
These results indicate that SAR is effective against pathogens that in noninduced plants are resisted through SAdependent defenses, whereas ISR is effective against pathogens that in noninduced plants are resisted through JA/ETdependent defenses. This suggests that SAR and ISR constitute a reinforcement of extant SA- or JA/ET-dependent
basal defense responses, respectively.
Original language | Undefined/Unknown |
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Pages (from-to) | 27-34 |
Number of pages | 8 |
Journal | Molecular Plant-Microbe Interactions |
Volume | 15 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2002 |
Keywords
- Plant biology (Botany)
- Life sciences