Grapevine crown gall disease

Vine with "tumors", caused by Grapevine Crown Gall (A. vitis) 

Grapevine Crown Gall is the most important bacterial disease of vines in the northern and eastern wine-growing regions of Europe. Particularly in years with severe winter frosts, there can be severe outbreaks of the disease ("tumors"), which can result in the complete death of the vines.

The pathogen is the Gram-negative bacterium Allorhizobium (Agrobacterium) vitis. The disease is of great importance for vine breeding and grafting, as transmission through latently infected propagation material is considered to be the most important route of spread. This was demonstrated in a vine grafting process we carried out in the laboratory: For this purpose, a stable red fluorescent protein (RFP)-expressing A. vitis strain was established using transposon technology and added to the propagation material to be grafted. This made it possible to visually localize the pathogen in the tissue using fluorescence or confocal microscopy.

Currently, detection in potentially infected propagation material is carried out by means of live isolation of the bacterial cells on semi-selective media and subsequent PCR detection using specific primers.