What is the Role of the Vir Genes on a Ti

Question

What is the role of the vir genes on a Ti plasmid?
A) to cause crow gall disease (virulence)
B) to confer resistance to viral infection
C) to initiate replication of the plasmid
D) to allow T-DNA transfer

Accepted Answer

The vir genes on a Ti plasmid are responsible for the transfer of T-DNA into the host plant cell, which enables the plasmid to integrate into the host cell's genome and direct the synthesis of various developmental and metabolic processes. The vir genes encode proteins that form a type IV secretion system, which creates a channel for the transfer of T-DNA from the bacterium into the plant cell.