What is the typical outcome of Agrobacterium-mediated transformation in plants?

• A. T-DNA transfers into plant cells that integrates into the plant genome, creating transgenic plants.
• B. T-DNA remains in plasmid form and does not integrate.
• C. DNA is delivered to chloroplasts only.
• D. Only roots are transformed.

Answer: (A)

The key idea being tested is that Agrobacterium delivers the T-DNA into plant cells and that this DNA often becomes integrated into the plant’s nuclear genome, giving rise to stable, heritable transgenic plants. In this natural process, the T-DNA region from the Ti plasmid is transferred into the plant cell and, through the plant’s DNA repair machinery, is inserted into the plant genome. Once integrated, the new genes are expressed and inherited in subsequent generations, which is the hallmark of a transgenic plant. This differs from a scenario where the T-DNA simply remains as an independent plasmid and isn’t integrated, which would usually result in only transient expression without stable inheritance. Agrobacterium-mediated transformation targets the plant nucleus and is not confined to chloroplasts, and the tissue that can be transformed depends on the experimentation setup (not limited to roots).