Final Answer:
In Agrobacterium tumefaciens, the vir proteins VirA and VirG perform analogous functions to TraY and TraI in the process of transferring Ti plasmid genes into plant cells.
Step-by-step explanation:
Agrobacterium tumefaciens is a bacterium that transfers a segment of its Ti (tumor-inducing) plasmid, known as T-DNA, into plant cells, leading to the formation of crown gall tumors. VirA and VirG are part of the vir gene system in Agrobacterium. VirA detects plant signals, inducing the expression of other vir genes. VirG acts as a transcriptional activator, regulating the expression of the genes involved in T-DNA transfer.
In the context of bacterial conjugation, TraY and TraI are proteins in the F plasmid of Escherichia coli that perform similar roles, facilitating the transfer of genetic material to recipient cells.