200. Which one of the following is commonly used as a selection marker for developing transgenic
plants?
A. Green fluorescent protein
B. 𝛽-lactamase
C. 𝛽-galactosidase
D. Hygromycin phosphotransferase

Answer: D. Hygromycin phosphotransferase

Explanation:

When developing transgenic plants, selection markers are crucial for identifying successfully transformed plants. These markers allow scientists to distinguish between plants that have incorporated the desired genetic material and those that have not.

• Hygromycin phosphotransferase (D): This is a widely used selection marker in plant biotechnology. It confers resistance to hygromycin, an antibiotic, enabling the growth of only the transformed plant cells or tissues that express this marker.

Other options:

• Green fluorescent protein (A): While GFP is a useful marker for visualizing gene expression, it is not commonly used as a selection marker in transgenic plants.

• β-lactamase (B): This marker confers resistance to antibiotics like ampicillin, but it is more commonly used in bacterial systems rather than in plants.

• β-galactosidase (C): Often used in molecular biology as a reporter gene, β-galactosidase is not typically used as a selection marker in plants.

Conclusion:

The hygromycin phosphotransferase marker (D) is the most commonly used for selecting transgenic plants, making it the correct answer.