The correct Option is : 4
Step 1: Role of Agrobacterium in genetic engineering.
Agrobacterium tumefaciens, a bacterium, naturally integrates a portion of its DNA (T-DNA) into plant cells. This process is leveraged in genetic engineering to insert target genes, such as those conferring herbicide resistance, into plants.
Step 2: Explanation of alternative techniques.
RNA interference (Option A): This technique silences specific genes but is not employed for introducing herbicide resistance.
CRISPR-Cas9 gene editing (Option B): While a precise genome editing tool, it is less frequently utilized for herbicide resistance compared to Agrobacterium-mediated methods.
Polymerase chain reaction (PCR) (Option C): PCR amplifies DNA sequences and is not used for transferring genes into plants. \[ \therefore \text{The correct answer is: Agrobacterium-mediated gene transfer.} \]
Answer the following questions:
(a) [(i)] Explain how some strains of Bacillus thuringiensis produce proteins that kill certain insects such as lepidopterans but do not kill the Bacillus.
[(ii)] How is the above mechanism exploited for the production of Bt cotton plant by biotechnologists?
(b) [(i)] Explain how the amplification of gene of interest is done using PCR.
[(ii)] State two applications of the desired amplified fragment of DNA.