Early detection of Agrobacterium tumefaciens in symptomless artificially inoculated chrysanthemum and peach plants using PCR

A PCR-based procedure has been developed to detect Agrobacterium tumefaciens in chrysanthemum and peach plants that had been inoculated in the roots but were symptomless. The procedure was simple and rapid, and discriminated tumorigenic from non-tumorigenic forms of Agrobacterium. It was highly sensitive since the target sequence was detected in spiked samples containing only 10 +/- 5 cfu/g fresh tissue of Agrobacterium. The PCR protocol detected the bacteria in the stems of both plant species while bacteria were not always detected by dilution plating, the current method for detecting A. tumefaciens in plants. The protocol needs further studies using naturally infected plant material, but once tested and validated might be used in laboratories that certify plant propagation material. It could then also be suitable for ecological and epidemiological studies on crown gall. In our work some evidence was obtained that A. tumefaciens may be translocated to the stem of root-inoculated peach plants.