Q.30 Prior exposure of plants to pathogens is known to increase resistance to future pathogen attacks.
This phenomenon is known as
(A) systemic acquired resistance (B) hypersensitive response
(C) innate immunity (D) antibody mediated response

Prior exposure of plants to pathogens triggers systemic acquired resistance (SAR), enhancing defense against future attacks. This SEO-optimized article covers the correct answer, detailed explanations of all options, and key plant immunity concepts.

Correct Answer

The phenomenon where prior exposure of plants to pathogens increases resistance to future attacks is systemic acquired resistance (SAR), option (A).​

SAR activates after localized infection, spreading protection plant-wide via salicylic acid signaling and pathogenesis-related proteins.​

Option Explanations

Systemic Acquired Resistance (A)

SAR provides long-lasting, broad-spectrum resistance following an initial pathogen encounter, often linked to hypersensitive response or necrosis.​

It involves salicylic acid accumulation, activating defense genes systemically in uninfected tissues.​

Hypersensitive Response (B)

Hypersensitive response (HR) causes rapid, localized cell death at the infection site to contain pathogens, not systemic resistance.​​

HR triggers SAR but is a local reaction, limiting spread without conferring whole-plant immunity.​​

Innate Immunity (C)

Innate immunity refers to plants’ baseline, constitutive defenses like physical barriers and pattern recognition receptors, active without prior exposure.​

Unlike SAR, it does not require pathogen priming for enhanced response.​

Antibody Mediated Response (D)

Antibody-mediated response is an animal-specific adaptive immunity feature involving antibodies, absent in plants lacking such systems.​

Plants rely on RNA interference, hormones, and protein-based defenses instead.​