Crown Gall is a plant tumour disease responsible for huge losses in flower, fruit and nut crops. Its name is derived from tumour-like swellings (galls) created at the crown of the host plant, just above the ground. The bacterium transfers part of its DNA to its host, which changes the latters genome, causing tumours and other malformations.
In the 1970s a closely related natural soil bacterium was identified, referred to as strain K84, which produced an antibiotic antidote to the Crown Gall bacterium. However, as University of Adelaide professor Dr Allan Kerr was able to recognise, this antidote was flawed in one critical respect : the harmful Crown gall bacterial pathogen, Agrobacterium tumefaciens, was actually able to develop immunity to K84s antibiotic. Indeed, the very genetic material responsible for reproducing the antibiotic agent was transferred from the K84 strand to pathogenic organisms like the Crown Gall bacterium.
In what was to be the first real application of plant genetic engineering, the Professor decided to remove the piece of K84s DNA that allowed the transfer of the antibiotic gene to the Crown Gall bacterium. This new version of K84 was named K1026, and went on the Australian market as Nogall in the 1980s.
Nogall is used to control Crown Gall by treating disease-free propagation stock. It is applied in an aqueous solution to seeds, seedlings and cuttings before planting and works by protecting wound sites from infection . This new strain is the first genetically engineered micro-organism to be sold live to the public. Its significant commercial potential in major world producers of stone fruits and nuts is highlighted by its user-friendliness, its long shelf-life, and its harmlessness to produce from plants it has treated, as well as to the surrounding environment.
Dr Kerr won the first Australia Prize for science in 1990 for this invention. Products using the same technology now exist in many forms worldwide, and the product Nogall itself is currently licensed to the NSW company Bio-Care Technology.