Question

Complete the following statement with the correct option:
Agrobacterium-mediated plant transformation in the laboratory

• A. is not influenced by the genotype of the host plant.
• B. always leads to integration of a single copy of the T-DNA in the host cell.
• C. is facilitated by the use of selection marker genes to allow preferential growth of transformed cells.
• D. requires the expression of opine genes for the production of transgenic plants.

Hint:

Selection marker genes help identify transformed cells in the lab by providing resistance to a selective agent like an antibiotic or herbicide.

Answer 1

The Correct Option is C

Step 1: Understand the Agrobacterium-mediated transformation process 
Agrobacterium tumefaciens naturally transfers a segment of its DNA (T-DNA) into the plant genome, making it a useful tool in genetic engineering of plants. 
Step 2: Identify the role of selection marker genes 
In the laboratory, to ensure only the transformed cells survive and grow, selection marker genes (e.g., antibiotic or herbicide resistance genes) are inserted along with the gene of interest into the T-DNA. These allow preferential growth of successfully transformed cells. 
Step 3: Eliminate incorrect statements 
(1) is incorrect — the efficiency of transformation is often influenced by the genotype of the host plant.
(2) is incorrect — the T-DNA integration can be single or multiple copies.
(4) is incorrect — opine gene expression is not essential for transformation; it was more relevant in wild-type Agrobacterium interactions.