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:
नीचे दो कथन दिए गए हैं, एक को अभिकथन (A) और दूसरे को कारण (R) के रूप में लेबल किया गया है:
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:
EXPLANATION
Crop Botany, Geography & Agronomy
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.
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