Question

With reference to virulence (vir) region of nopaline type Ti plasmid of Agrobacterium tumefaciens, match Group-I (vir gene) and Group-II (coded protein) in CORRECT combination.

Which one of the following combinations is correct?

• A. P-IV, Q-III, R-II, S-I
• B. P-IV, Q-II, R-I, S-II
• C. P-IV, Q-III, R-I, S-III
• D. P-I, Q-III, R-II, S-IV

Hint:

In Agrobacterium tumefaciens, virulence proteins play key roles in T-DNA transfer, and each gene product has specific functions, such as binding to T-DNA and facilitating transport.

Answer 1

The Correct Option is B

Step 1: Understanding the Virulence (vir) Region.
In Agrobacterium tumefaciens, the virulence (vir) region on the Ti plasmid contains genes that are essential for the transfer of T-DNA to plant cells. These genes code for proteins that facilitate the process of T-DNA transfer and integration into the host plant genome.
Step 2: Analyzing the Options.
- (A) P-IV, Q-III, R-II, S-I: This is incorrect. Vir A is related to sensor protein, while other pairings are incorrect as well.
- (B) P-IV, Q-II, R-I, S-II: This is correct. Vir A (P) is associated with the sensor protein, Vir B (Q) with topoisomerase, Vir E (R) with the membrane protein, and Vir D (S) with the single strand T-DNA binding protein.
- (C) P-IV, Q-III, R-I, S-III: This is incorrect, as the protein pairings do not match correctly.
- (D) P-I, Q-III, R-II, S-IV: This is incorrect. Vir A corresponds to sensor protein, not single strand T-DNA binding protein.
Step 3: Conclusion.
The correct answer is (B) P-IV, Q-II, R-I, S-II.