Protoplast transformation — agents that stimulate direct DNA uptake Direct uptake of DNA by plant protoplasts (cells without a wall) can be experimentally stimulated using which of the following reagents?

Introduction / Context:
Protoplast transformation leverages the absence of a rigid wall to introduce exogenous DNA. The efficiency of direct DNA uptake depends on chemical facilitators that promote membrane fusion or transient permeability.

Given Data / Assumptions:

• PEG is widely used to induce membrane perturbation and DNA uptake.
• Decanal is unrelated to protoplast transformation chemistry.
• Luciferin is a bioluminescent substrate used for reporters, not for DNA uptake.

Concept / Approach:

PEG-mediated transformation mixes protoplasts with purified DNA and PEG in an osmoticum; PEG promotes membrane coalescence and facilitates DNA internalization. Divalent cations may assist, but PEG is the hallmark reagent. Decanal and luciferin do not stimulate uptake in this context.

Step-by-Step Solution:

Verification / Alternative check:

Classic plant transformation protocols consistently employ PEG to achieve reproducible DNA uptake into protoplasts, confirming its role.

Why Other Options Are Wrong:

Decanal and luciferin serve unrelated functions; ‘‘All of these’’ is incorrect because only PEG promotes uptake here. Calcium chloride alone without PEG is insufficient for high-efficiency plant protoplast transformation.

Common Pitfalls:

Confusing PEG-mediated chemical transformation with electroporation or liposome-mediated delivery, which are distinct methods.

Final Answer:

Polyethylene glycol (PEG)