Agrobacterium are Alphaproteobacteria common in most soils that closely interact with plants in two respects. Firstly, and as a general trait of the whole taxon, they are rhizospheric bacteria saprophytically living in the root environment (i.e. rhizosphere) of numerous plants. Rhizospheric interactions are generally considered to be of commensal type with no detrimental effect to the plant, bu...

Agrobacterium tumefaciens is a Gramnegative rod-shaped bacterium that is commonly found in the rhizosphere of many plants, where it survives on root exudates. It will infect a plant only through a wound site (which often occurs in nursery stock through transplanting and grafting and in vineyards through pruning). Galls typically form at the crown (the point at the soil line where the main root ...

Crown gall tumors collected from naturally infected plants of 7 grapevine varieties were analysed for the presence of opines. Eighty-five of the tested 90 samples contained known Agrobacterium vitis-induced opines. Octopine was the most common, it was found in 50 samples. Twentyeight crown galls contained nopaline and 8 were vitopine positive. There was only one tumor that contained two opines,...

Opines are low-molecular-weight metabolites specifically biosynthesized by agrobacteria-transformed plant cells when plants struck crown gall and hairy root diseases, which cause uncontrolled tissue overgrowth. Transferred DNA is sustainably incorporated into the genomes of transformed cells, so that opines constitute a persistent biomarker infection pathogenic agrobacteria can be targeted for ...