Given below are two statements, one is labelled as Assertion (A)...

All Subjects General Agriculture, Crop Production & Soils Cell Biology, Genetics, Physiology, Biochemistry & Plant Protection Genetics, Plant Pathology, Seed Science & Agricultural Microbiology Food & Industrial Microbiology, Rural Development

ICAR AIEEA PG 2024 - Plant Sciences

Arranging Order

Arrange the following events in the correct order:

(A) Restoration of Effector Triggered Susceptibility by Pathogen

(B) Effector triggered susceptibility by Pathogen

(C) Effector triggered immunity by Plant

(D) PAMP triggered immunity by Plant

Choose the correct answer from the options given below:

निम्नलिखित घटनाओं को सही क्रम में व्यवस्थित कीजिए:

(A) रोगजनक द्वारा इफेक्टर ट्रिगर्ड ससेप्टिबिलिटी की पुनर्स्थापना (Restoration of Effector Triggered Susceptibility by Pathogen)

(B) रोगजनक द्वारा इफेक्टर ट्रिगर्ड ससेप्टिबिलिटी (Effector triggered susceptibility by Pathogen / ETS)

(C) पौधे द्वारा इफेक्टर ट्रिगर्ड इम्युनिटी (Effector triggered immunity by Plant / ETI)

(D) पौधे द्वारा पीएएमपी ट्रिगर्ड इम्युनिटी (PAMP triggered immunity by Plant / PTI)

नीचे दिए गए विकल्पों में से सही उत्तर चुनिए:

(D), (B), (C), (A) (D), (B), (C), (A) (A), (B), (C), (D) (A), (B), (C), (D) (B), (A), (D), (C) (B), (A), (D), (C) (C), (B), (D), (A) (C), (B), (D), (A)

Zig-Zag Model of Plant Immune System:

The co-evolutionary arms race between plants and pathogens is described in four evolutionary phases:

Phase 1 (D) - PAMP-Triggered Immunity (PTI): Plant pattern recognition receptors (PRRs) recognize pathogen-associated molecular patterns (PAMPs/MAMPs like flagellin or chitin), activating basal defense (PTI).
Phase 2 (B) - Effector-Triggered Susceptibility (ETS): Successful pathogens inject specialized virulence effectors into host cells to suppress PTI, resulting in disease (ETS).
Phase 3 (C) - Effector-Triggered Immunity (ETI): Plants evolve nucleotide-binding leucine-rich repeat (NBS-LRR) resistance proteins ($R$ genes) that directly or indirectly recognize specific pathogen effectors (now called avirulence / Avr factors), triggering an accelerated, robust hypersensitive defense response (ETI).
Phase 4 (A) - Restoration of ETS: Natural selection drives the pathogen to shed or alter recognized effectors or acquire novel effectors that suppress ETI, restoring effector-triggered susceptibility.

Therefore, the correct chronological sequence is (D) $\rightarrow$ (B) $\rightarrow$ (C) $\rightarrow$ (A). Correct Answer: Option 1.

विस्तृत व्याख्या:

Zig-Zag Model of Plant Immune System (पादप प्रतिरक्षा प्रणाली का जिग-जैग मॉडल - Jones & Dangl, 2006):

The co-evolutionary arms race between plants and pathogens is described in four evolutionary phases:

Phase 1 (D) - PAMP-Triggered Immunity (PTI): Plant pattern recognition receptors (PRRs) recognize pathogen-associated molecular patterns (PAMPs/MAMPs like flagellin or chitin), activating basal defense (PTI).
Phase 2 (B) - Effector-Triggered Susceptibility (ETS): Successful pathogens inject specialized virulence effectors into host cells to suppress PTI, resulting in disease (ETS).
Phase 3 (C) - Effector-Triggered Immunity (ETI): Plants evolve nucleotide-binding leucine-rich repeat (NBS-LRR) resistance proteins ($R$ genes) that directly or indirectly recognize specific pathogen effectors (now called avirulence / Avr factors), triggering an accelerated, robust hypersensitive defense response (ETI).
Phase 4 (A) - Restoration of ETS: Natural selection drives the pathogen to shed or alter recognized effectors or acquire novel effectors that suppress ETI, restoring effector-triggered susceptibility.

Therefore, the correct chronological sequence is (D) $\rightarrow$ (B) $\rightarrow$ (C) $\rightarrow$ (A). Correct Answer: Option 1.

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

ICAR AIEEA PG 2024 - Plant Sciences

Assertion & Reason

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R):

Assertion (A) : The secondary spread of the pathogen propagules that are identical in virulence is mostly responsible for epidemics.

Reason (R) : Secondary propagules are mostly asexually produced.

In light of the above statements, choose the correct answer from the options given below:

नीचे दो कथन दिए गए हैं, एक को अभिकथन (A) और दूसरे को कारण (R) के रूप में लेबल किया गया है:

अभिकथन (A) : रोगजनक प्रवर्ध्यों (propagules) का द्वितीयक प्रसार, जो उग्रता (virulence) में समरूप होते हैं, मुख्य रूप से महामारी (epidemics) के लिए उत्तरदायी होता है।

कारण (R) : द्वितीयक प्रवर्ध्य (secondary propagules) अधिकांशतः अलैंगिक रूप से उत्पन्न होते हैं।

उपरोक्त कथनों के आलोक में, नीचे दिए गए विकल्पों में से सही उत्तर चुनिए:

Both (A) and (R) are true and (R) is the correct explanation of (A) (A) और (R) दोनों सत्य हैं और (R), (A) की सही व्याख्या है Both (A) and (R) are true but (R) is NOT the correct explanation of (A) (A) और (R) दोनों सत्य हैं लेकिन (R), (A) की सही व्याख्या नहीं है (A) is true but (R) is false (A) सत्य है लेकिन (R) असत्य है (A) is false but (R) is true (A) असत्य है लेकिन (R) सत्य है

Epidemiology of Polycyclic Plant Diseases:

Assertion (A) is TRUE: In polycyclic plant diseases (e.g., late blight of potato, powdery mildews, rusts), explosive compound-interest epidemics are driven by multiple repeated cycles of secondary infection occurring within a single growing season.
Reason (R) is TRUE and correctly explains (A): Secondary propagules (e.g., conidia, sporangia, urediniospores) are produced asexually through mitosis. Because they are clonal products, they are genetically identical in virulence to the parent strain, allowing millions of equally virulent spores to rapidly colonize neighboring plants without meiotic gene segregation or loss of fitness.

Therefore, both (A) and (R) are true and (R) is the correct explanation of (A). Correct Answer: Option 1.

विस्तृत व्याख्या:

Epidemiology of Polycyclic Plant Diseases (पादप महामारी विज्ञान एवं द्वितीयक प्रसार):

Assertion (A) is TRUE: In polycyclic plant diseases (e.g., late blight of potato, powdery mildews, rusts), explosive compound-interest epidemics are driven by multiple repeated cycles of secondary infection occurring within a single growing season.
Reason (R) is TRUE and correctly explains (A): Secondary propagules (e.g., conidia, sporangia, urediniospores) are produced asexually through mitosis. Because they are clonal products, they are genetically identical in virulence to the parent strain, allowing millions of equally virulent spores to rapidly colonize neighboring plants without meiotic gene segregation or loss of fitness.

Therefore, both (A) and (R) are true and (R) is the correct explanation of (A). Correct Answer: Option 1.

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

ICAR AIEEA PG 2024 - Plant Sciences

Assertion & Reason

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R):

Assertion (A) : Viruses are molecular parasites.

Reason (R) : Viruses depend on host for their basic functions like replication.

In light of the above statements, choose the correct answer from the options given below:

अभिकथन (A) : विषाणु (viruses) आण्विक परजीवी (molecular parasites) हैं।

कारण (R) : विषाणु अपने बुनियादी कार्यों जैसे प्रतिकृति (replication) के लिए पोषक (host) पर निर्भर करते हैं।

उपरोक्त कथनों के आलोक में, नीचे दिए गए विकल्पों में से सही उत्तर चुनिए:

Nature of Viruses as Molecular Parasites:

Assertion (A) is TRUE: Viruses are non-cellular sub-microscopic entities comprising only genetic material (DNA or RNA) enclosed in a protein coat. They are referred to as 'molecular parasites' because they possess genetic information but lack an independent metabolic machinery.
Reason (R) is TRUE and correctly explains (A): Viruses lack ribosomes, ATP-generating enzymes, transfer RNAs, and metabolic substrates. Consequently, they are obligate intracellular parasites that completely hijack the host cell's molecular machinery (ribosomes, polymerases, amino acids, and energy) to synthesize viral proteins and replicate viral genomes.

Therefore, both (A) and (R) are true and (R) is the correct explanation of (A). Correct Answer: Option 1.

विस्तृत व्याख्या:

Nature of Viruses as Molecular Parasites (विषाणु: आण्विक परजीवी):

Assertion (A) is TRUE: Viruses are non-cellular sub-microscopic entities comprising only genetic material (DNA or RNA) enclosed in a protein coat. They are referred to as 'molecular parasites' because they possess genetic information but lack an independent metabolic machinery.
Reason (R) is TRUE and correctly explains (A): Viruses lack ribosomes, ATP-generating enzymes, transfer RNAs, and metabolic substrates. Consequently, they are obligate intracellular parasites that completely hijack the host cell's molecular machinery (ribosomes, polymerases, amino acids, and energy) to synthesize viral proteins and replicate viral genomes.

Therefore, both (A) and (R) are true and (R) is the correct explanation of (A). Correct Answer: Option 1.

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

ICAR AIEEA PG 2024 - Plant Sciences

Assertion & Reason

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R):

Assertion (A) : Biotrophs can be easily cultured in artificial medium.

Reason (R) : Biotrophs lost their independent growth due to co-evolution with the host.

In light of the above statements, choose the most appropriate answer from the options given below:

अभिकथन (A) : अविकल्पी परजीवियों (Biotrophs) को कृत्रिम माध्यम (artificial medium) में आसानी से संवर्धित किया जा सकता है।

कारण (R) : बायोट्रोफ्स ने पोषक (host) के साथ सह-विकास (co-evolution) के कारण अपनी स्वतंत्र वृद्धि क्षमता खो दी है।

उपरोक्त कथनों के आलोक में, नीचे दिए गए विकल्पों में से सबसे उपयुक्त उत्तर चुनिए:

Both (A) and (R) are correct and (R) is the correct explanation of (A) (A) और (R) दोनों सही हैं और (R), (A) की सही व्याख्या है Both (A) and (R) are correct but (R) is NOT the correct explanation of (A) (A) और (R) दोनों सही हैं लेकिन (R), (A) की सही व्याख्या नहीं है (A) is correct but (R) is not correct (A) सही है लेकिन (R) सही नहीं है (A) is not correct but (R) is correct (A) सही नहीं है लेकिन (R) सही है

Nature of Obligate Biotrophs:

Assertion (A) is INCORRECT (False): Obligate biotrophic pathogens (such as rust fungi Puccinia, powdery mildews Erysiphe, downy mildews Peronospora, and viruses) cannot be cultured on standard synthetic nutrient agar media because they strictly depend on metabolic signals and living host plant cytoplasm to survive and reproduce.
Reason (R) is CORRECT (True): Over millions of years of co-evolution and genome reduction with their plant hosts, biotrophic organisms have lost critical metabolic biosynthetic genes (such as nitrate and sulfate assimilation pathways and inorganic nitrogen reduction), rendering them entirely reliant on living host cellular metabolism for their nutrition.

Therefore, (A) is not correct but (R) is correct. Correct Answer: Option 4.

विस्तृत व्याख्या:

Nature of Obligate Biotrophs (अविकल्पी परजीवी / बायोट्रोफ्स की प्रकृति):

Assertion (A) is INCORRECT (False): Obligate biotrophic pathogens (such as rust fungi Puccinia, powdery mildews Erysiphe, downy mildews Peronospora, and viruses) cannot be cultured on standard synthetic nutrient agar media because they strictly depend on metabolic signals and living host plant cytoplasm to survive and reproduce.
Reason (R) is CORRECT (True): Over millions of years of co-evolution and genome reduction with their plant hosts, biotrophic organisms have lost critical metabolic biosynthetic genes (such as nitrate and sulfate assimilation pathways and inorganic nitrogen reduction), rendering them entirely reliant on living host cellular metabolism for their nutrition.

Therefore, (A) is not correct but (R) is correct. Correct Answer: Option 4.

Explanation not matching this question? क्या व्याख्या इस प्रश्न से मेल नहीं खा रही? Report

ICAR AIEEA PG 2024 - Plant Sciences

Assertion & Reason

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R):

Assertion (A) : Rust is incited not only by fungi but also by other organisms.

Reason (R) : Colour of rust pustule reveal its causal agent.

In light of the above statements, choose the correct answer from the options given below:

अभिकथन (A) : किट्ट (Rust) न केवल कवकों द्वारा बल्कि अन्य जीवों द्वारा भी उत्पन्न होता है।

कारण (R) : रस्ट पुस्ट्यूल (पपड़ी) का रंग इसके रोगकारक जीव को प्रकट करता है।

उपरोक्त कथनों के आलोक में, नीचे दिए गए विकल्पों में से सही उत्तर चुनिए:

Rust Diseases in Plants:

Assertion (A) is TRUE: While the vast majority of agricultural rust diseases are incited by basidiomycete fungi of the order Pucciniales (e.g., Puccinia, Uromyces), rust diseases are also caused by other organisms, such as algae (e.g., Red rust of tea, mango, and coffee caused by the parasitic green alga Cephaleuros virescens).
Reason (R) is TRUE: The characteristic color of rust lesions and pustules—such as red/orange-brown (algal rust Cephaleuros), orange/yellow (yellow/stripe rust Puccinia striiformis), brown (leaf rust P. triticina), or black (black stem rust P. graminis)—is diagnostic of the specific spore stage and causal pathogen.
However, the color of the pustule does not provide the causal biological explanation of why organisms other than fungi can incite rust diseases.

Therefore, both (A) and (R) are true, but (R) is NOT the correct explanation of (A). Correct Answer: Option 2.

विस्तृत व्याख्या:

Rust Diseases in Plants (पादपों में रस्ट रोग):

Assertion (A) is TRUE: While the vast majority of agricultural rust diseases are incited by basidiomycete fungi of the order Pucciniales (e.g., Puccinia, Uromyces), rust diseases are also caused by other organisms, such as algae (e.g., Red rust of tea, mango, and coffee caused by the parasitic green alga Cephaleuros virescens).
Reason (R) is TRUE: The characteristic color of rust lesions and pustules—such as red/orange-brown (algal rust Cephaleuros), orange/yellow (yellow/stripe rust Puccinia striiformis), brown (leaf rust P. triticina), or black (black stem rust P. graminis)—is diagnostic of the specific spore stage and causal pathogen.
However, the color of the pustule does not provide the causal biological explanation of why organisms other than fungi can incite rust diseases.