Question

Tissue culture for plant transformation should be free from

• A. Somaclonal variation
• B. Agrobacterium co-cultivation
• C. High rate of shoot regeneration
• D. High rate of root regeneration

Hint:

Somaclonal variation introduces unwanted genetic mutations and phenotypic abnormalities during tissue culture.
Minimizing this variation is essential to ensure that any observed changes in transgenic plants are due solely to the introduced transgene.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Plant tissue culture uses the totipotency of plant cells to regenerate whole plants from cultured tissues (explants).
For plant transformation, maintaining genetic stability during the culture phase is important to ensure uniform transgenic lines.

Step 2: Detailed Explanation:
Somaclonal variation refers to genetic, cytogenetic, or epigenetic variations that occur in plants regenerated from in vitro tissue culture.
These variations are caused by the stress of tissue culture, exposure to plant growth regulators, and chromosome instability during callus phases, leading to mutations, gene duplications, or DNA methylation changes.
For plant transformation, somaclonal variation is highly undesirable.
The goal of genetic transformation is to introduce a specific transgene into a clean, well-characterized plant genetic background.
If the tissue culture process introduces somaclonal variation, the regenerated transgenic plants may display off-types, abnormal phenotypes, or reduced fertility that are unrelated to the transgene itself.
This makes it difficult to evaluate the true effect of the transgene and can complicate the regulatory approval of the transgenic event.
Therefore, transformation protocols are optimized to minimize somaclonal variation.
In contrast, Agrobacterium co-cultivation is required for gene transfer, and high rates of shoot and root regeneration are desirable traits to recover transgenic plants.

Step 3: Final Answer:
Tissue culture for plant transformation should be free from Somaclonal variation, which corresponds to Option (A).