Induced resistance

Definition

Induced resistance refers to a plant's ability to activate its defense mechanisms in response to specific stimuli, such as pathogen attacks or herbivore feeding. This adaptive response enhances the plant's ability to resist subsequent threats, allowing it to mobilize resources and produce defensive compounds more effectively than it would under normal conditions.

5 Must Know Facts For Your Next Test

1. Induced resistance can be triggered by various factors including herbivore damage, pathogen infection, or even the presence of certain signaling molecules like jasmonic acid.
2. Unlike constitutive defenses, which are always present, induced resistance is a dynamic response that can be activated and deactivated as needed.
3. Plants often communicate with neighboring plants through volatile organic compounds (VOCs) when they experience stress, leading to a preemptive activation of induced resistance in nearby plants.
4. Induced resistance is not only effective against pathogens but can also enhance the plant's overall fitness by improving growth and reproductive success when conditions allow.
5. Research into induced resistance has potential applications in agriculture, as it may lead to the development of crops that require fewer chemical pesticides due to their enhanced natural defenses.

Review Questions

• How does induced resistance differ from constitutive defenses in plants, and what implications does this difference have for plant survival?
  • Induced resistance differs from constitutive defenses in that it is not always active; instead, it is activated in response to specific stimuli like herbivore or pathogen attacks. This allows plants to conserve resources by only deploying defenses when necessary. The ability to induce resistance enhances plant survival by enabling them to respond more effectively to threats while minimizing energy expenditure on constant defense mechanisms.
• Discuss the role of signaling molecules in the process of induced resistance and how they contribute to a plant's defense strategy.
  • Signaling molecules such as jasmonic acid and salicylic acid play critical roles in initiating and regulating the process of induced resistance. When a plant detects damage from herbivores or pathogens, these molecules are produced and trigger signaling pathways that lead to the expression of defense genes. This results in the production of defensive compounds like phytoalexins, strengthening the plant’s ability to fend off future attacks and ensuring a coordinated defense strategy.
• Evaluate the potential benefits and challenges of utilizing induced resistance in agricultural practices aimed at pest management.
  • Utilizing induced resistance in agriculture presents several benefits, including reduced reliance on chemical pesticides and improved crop resilience against pests and diseases. However, challenges include the variability of induced responses among different plant species and environmental conditions, as well as the need for further research to understand the mechanisms involved. Additionally, there may be a risk of over-reliance on induced resistance leading to pest adaptation or the emergence of resistant strains, which necessitates a balanced approach integrating various pest management strategies.

Related terms

Systemic Acquired Resistance (SAR): A whole-plant defense response that is triggered by a localized infection and provides enhanced resistance against a broad spectrum of pathogens.

Priming: A phenomenon where plants are prepared for a faster and stronger defense response upon subsequent exposure to stressors, without an immediate activation of defenses.

Phytoalexins: Small molecules produced by plants in response to stress, such as pathogen attack, which have antimicrobial properties and contribute to plant defense.