Abstract
Agrobacterium tumefaciens is unique in its ability to transfer bacterial DNA to plant cells. The virulence regulon of the Ti plasmid of A. tumefaciens contains 24 genes organized in six vir operons that are involved in the DNA transfer process. The virB operon consists of 11 genes, all of which have been characterized as to their primary structure. virB4 and virB11 encode proteins that possess a potential ATP-binding site and are localized in the inner membrane fraction of A.tumefaciens. In this study, we focus on the product of virB4 which is the largest gene in the operon. Purified VirB4 protein was shown to possess ATPase activity. To test the essentiality of virB4 in the T-DNA transfer process, non-polar mutants were constructed using a Tn5pvirB transposon in which the virB promoter faces outward. Several independent mutants were isolated and the precise insertion sites in virB4 were confirmed by sequence analysis. These mutants were tested for T-DNA transfer ability by agroinfection and tumorigenicity by inoculation in Brassica and Datura. All mutants were agroinfection negative and tumorigenicity negative. These data strongly suggest that VirB4 is essential for T-DNA transfer from A. tumefaciens to plants.
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© 1993 Springer Science+Business Media Dordrecht
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Shirasu, K., Koukolíková-Nicola, Z., Hohn, B., Kado, C.I. (1993). VirB4 is an Inner Membrane-Associated Protein Essential for T-DNA Transfer from Agrobacterium Tumefaciens to Plants. In: Nester, E.W., Verma, D.P.S. (eds) Advances in Molecular Genetics of Plant-Microbe Interactions, Vol. 2. Current Plant Science and Biotechnology in Agriculture, vol 14. Springer, Dordrecht. https://doi.org/10.1007/978-94-017-0651-3_11
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DOI: https://doi.org/10.1007/978-94-017-0651-3_11
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