Facts about Agrobacterium tumefaciens Which statement best captures its host range and disease association?
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AIt causes crown gall disease of plants and primarily infects dicotyledonous angiosperms
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BIt routinely infects gymnosperms in nature
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CIt exclusively infects monocot crops such as cereals
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DIt does not cause disease; it is only a laboratory tool
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EIt infects only algae and fungi
Answer
Correct Answer: It causes crown gall disease of plants and primarily infects dicotyledonous angiosperms
Explanation
Introduction / Context:Agrobacterium tumefaciens is both a plant pathogen and a cornerstone of plant genetic engineering. A clear understanding of its natural host range and the disease it causes helps students connect basic pathology with biotechnology applications.
Given Data / Assumptions:
- Crown gall is the classic disease symptom associated with Agrobacterium.
- Natural susceptibility varies across plant groups.
- The question seeks the most accurate, concise statement.
Concept / Approach:Agrobacterium induces crown galls mainly on dicotyledonous plants (e.g., rose, grapevine). While engineered methods can extend transformation to some monocots, natural infections are largely dicot-biased. Reports of gymnosperm infection are limited and not routine in nature, making the generalization inaccurate. Therefore, the best answer emphasizes crown gall disease and primary dicot host range.
Step-by-Step Solution:
Identify disease association: crown gall tumors at wound sites.Recall host preference: primarily dicot angiosperms.Exclude overstated claims about gymnosperms or monocots.Select the statement that includes both disease and correct host range.Verification / Alternative check:Plant pathology references describe classic dicot hosts (e.g., grape, stone fruits). Agricultural disease reports align with dicot susceptibility; monocot infections are rare and typically require lab intervention.
Why Other Options Are Wrong:
- Gymnosperm routine infection: not broadly supported.
- Exclusive monocot infection: opposite of observed natural host range.
- No disease: contradicted by well-documented pathology.
- Algae/fungi hosts: incorrect kingdom.
Common Pitfalls:Confusing laboratory transformation capability with natural pathogenesis. Success in engineered monocot transformation does not imply broad natural infection.
Final Answer:It causes crown gall disease of plants and primarily infects dicotyledonous angiosperms