Selecting herbicide-resistant somaclones via tissue culture Plant tissue culture and somaclonal variation can be exploited to select variants with altered traits. Which option correctly describes a common selection goal achieved using this approach?
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AIsolation of herbicide-resistant somaclones
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BIsolation of somaclones not resistant to herbicide (by design)
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CDirect selection of insecticide-resistant insects
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DSelection of lines not resistant to insecticides
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ESelection for altered leaf color only
Answer
Correct Answer: Isolation of herbicide-resistant somaclones
Explanation
Introduction / Context:Somaclonal variation arises during plant cell and tissue culture and provides a pool of genetic and epigenetic diversity. By applying selection pressure in vitro, breeders and biotechnologists can isolate rare variants with desirable agronomic traits without transgene introduction.
Given Data / Assumptions:
- Callus or cell suspensions are exposed to selective agents (e.g., herbicides).
- Surviving cells are regenerated into plants and screened.
- Herbicide resistance is a well-established selection use case.
Concept / Approach:
Media supplemented with a herbicide (or analog) kills sensitive cells but allows spontaneous or induced resistant variants to proliferate. Regenerated plants are subsequently validated in greenhouse/field trials, and stable resistance can be fixed through breeding.
Step-by-Step Solution:
Establish callus/cell suspension from the crop of interest.Apply herbicide selection in culture medium.Recover resistant colonies and regenerate shoots/roots.Confirm resistance and agronomic performance in progeny.Verification / Alternative check:
Numerous case studies document tissue-culture selection of herbicide-tolerant variants (e.g., ALS/AHAS inhibitor tolerance), validating this application.
Why Other Options Are Wrong:
Options describing deliberate selection of non-resistance are illogical goals. Insecticide resistance of insects is not a plant tissue culture outcome. Pigment changes can occur but are not the common targeted objective in this context.
Common Pitfalls:
Confusing somaclonal selection with transgenic herbicide resistance; both exist but use different mechanisms.
Final Answer:
Isolation of herbicide-resistant somaclones