Polyamines enhance Agrobacterium tumefaciens vir gene induction and T-DNA transfer

We report here the enhancement of acetosyringone-mediated virulence gene induction in Agrobacterium tumefaciens by polyamines. The diamine putrescine and triamine spermidine enhanced vir gene induction when agrobacterial cells were treated prior to acetosyringone addition. An increase in polyamine levels was observed in Agroacterium following the polyamine treatments, which was positively correlated with the magnitude of vir gene induction. Plant transformation experiments have shown that modulation of polyamine levels in Agrobacterium results in the enhanced T-DNA transfer. These results suggest the involvement of polyamines in the processes that lead to vir gene induction and T-DNA transfer. And these findings may be useful in achieving a high transformation frequency in those plant species, which show minimal vir gene induction.