Question

Which of the following selectable marker genes is/are used for herbicide tolerance during genetic transformation of plants?

• A. ( hpt )
• B. ( bar )
• C. ( nptII )
• D. ( pmi )

Hint:

When selecting a marker gene for a genetic transformation project, consider the type of resistance needed (antibiotic or herbicide) and the compatibility with the crop species and agricultural practices.

Answer 1

The Correct Option is B

Selectable marker genes are crucial in the genetic engineering of plants, allowing researchers to identify and select cells that have been successfully transformed. These genes confer resistance to antibiotics or herbicides, which facilitates the selection process. Analysis of Options: 
(A) hpt (Hygromycin phosphotransferase): Incorrect. The hpt gene confers resistance to the antibiotic hygromycin, not herbicides. 
(B) bar (Bialaphos resistance gene): Correct. The bar gene encodes phosphinothricin acetyltransferase, which confers resistance to the herbicide phosphinothricin (glufosinate). This allows plants containing the bar gene to survive applications of certain broad-spectrum herbicides. 
(C) nptII (Neomycin phosphotransferase II): Incorrect. The nptII gene provides resistance to the antibiotics kanamycin and neomycin, not herbicides. 
(D) pmi (Phosphomannose isomerase): Incorrect. The pmi gene is used for positive selection on mannose-containing media but does not confer herbicide resistance. Conclusion:
Explanation: The bar gene is specifically used in plant biotechnology for imparting herbicide tolerance, making it a critical tool for developing genetically modified crops that can withstand herbicidal treatment, thus ensuring crop safety and weed control during cultivation.