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Association of single-stranded transferred DNA from Agrobacterium tumefaciens with tobacco cells
- Yusibov, V.M., Steck, T.R., Gupta, V., Gelvin, S.B.
- Proceedings of the National Academy of Sciences of the United States of America 1994 v.91 no.8 pp. 2994-2998
- protoplasts, structural genes, Agrobacterium radiobacter, plasmids, acetosyringone, Nicotiana tabacum, virulence, single-stranded DNA
- During the inception of crown gall tumorigenesis, the transferred DNA (T-DNA) is processed from the Ti (tumor inducing) plasmid of Agrobacterium tumefaciens and is transferred to plant cells. T-DNA p and transfer require the induction of vir (virulence) genes by phenolic compounds secreted by wounded plant cells. After vir gene induction, both single-stranded (T-strands) and double-stranded forms of processed T-DNA accumulate in the bacteria. Although current models favor the transfer of T-strands to plants, there has yet been no experimental evidence to show this. In this paper, we show that T-strands disappear from acetosyringone-induced A. tumefaciens within 30 min of bacterial cocultivation with tobacco protoplast. PCR analysis of T-DNA associated with protoplasts indicates that single-stranded, but not double-stranded, T-DNA can be detected in the plant cells within 30 min of bacterial cocultivation. Control experiments show that this T-DNA does not originate from lysed contaminating bacterial cells. T-DNA transfer depends on a functional bacterial virB operon. Protoplast infections using an A. tumefaciens virE mutant result in a low level of accumulation of T-strands in the plant cells.