Agrobacterium-mediated gene transfer—efficiency across plant groups With respect to natural transformation by <i>Agrobacterium tumefaciens</i> (Ti plasmid systems), which statement best reflects its inherent efficiency across major plant groups in classical practice?

Introduction / Context:
Agrobacterium naturally infects many dicotyledonous species, transferring T-DNA into the plant genome. Historically and inherently, this system was most efficient with dicots. Monocot transformation required later innovations (e.g., super-binary vectors, tissue wounding, specific genotypes), and biolistics was often used for cereals.

Given Data / Assumptions:

• Classical textbooks emphasize dicot susceptibility in natural infections.
• The question asks about inherent efficiency, not modern engineered workarounds.
• Binary vectors and improved protocols have expanded host range post-hoc.

Concept / Approach:
Differentiate between the natural proclivity of Agrobacterium and the broad applicability achieved through advanced methods. The inherently efficient group is dicots.

Step-by-Step Solution:

Verification / Alternative check:
Legacy transformation pipelines for tobacco, tomato, and petunia relied on Agrobacterium; cereal crops often required alternative methods until later protocol refinements.

Why Other Options Are Wrong:

• (b) Contradicts the natural host range.
• (c) Overgeneralizes current capabilities as inherent.
• (d) Reverses the historical pattern.

Common Pitfalls:
Conflating today’s engineered versatility with the organism’s native propensity.

Final Answer:
Only with dicots