A grapevine plant infected with the grapevine crown gall pathogen. Photo: Christopher Wong
A world free of grapevine crown gall disease is a step closer with the first field trial of a new method at Yalumba Nursery in the Barossa Valley.
The University of Adelaide's Associate Professor Iain Searle, School of Biological Sciences, and his team have created the world's first biological control for the disease which has caused a century of losses.
Crown gall disease is caused by Agrobacterium tumefaciens or Allorhizobium vitis bacteria, commonly found in soil, water and in vine sap and causes tumour-like growths on the plants.
The disease is particularly problematic for young plants as it is difficult to eradicate without prompt removal and destruction of the affected plants.
Some vineyards have reported more than 90 per cent of infected plants die within the first two years of planting resulting in significant economic costs and biosecurity concerns.
Associate Professor Searle said work first began in this space around 26 years ago at the University of Adelaide.
"Previous work on a biological control strain called A. vitis F2/5 had been done by Emeritus Professor Tom Burr's team at the New York State Agricultural Research Station, Cornell University," he said.
"Burr and team were able to identify important genes responsible for necrosis but were unable to develop a commercially useful strain."
Strain F2/5 had the ability to control crown gall, but it also caused necrosis of the grapevine tissue.
"We were able to modify one of the genes in F2/5 which prevented tissue necrosis yet retains its biocontrol ability using cutting-edge gene editing," said Associate Professor Searle.
The new strain called GTI-5813 will be injected into sterile peat, which will then be turned into a dip solution for application to vine grafts being produced at Yalumba Nursery.
"Yalumba Nursery is delighted to participate in the testing phase of this innovative and commercially relevant project, that has the potential to have a very significant positive impact on nursery grafting outcomes," said nursery manager Bethany Collins.
Associate Professor Searle's work has been supported by New South Wales-based biocontrol company Bio-Care Technology, which had also worked with Emeritus Professor Burr.
"The annual financial loss to the international grapevine nursery industry due to crown gall disease is estimated at $600 million while vineyards experience around $2 billion per year in losses," said Gary Bullard, CEO, Bio-Care Technology.
"For the past 26 years, Bio-Care Technology has investigated the potential commercial usefulness of a bacterium called Allorhizobium vitis, strain F2/5, targeting the biocontrol of crown gall disease in grapevines.
"If the new, non-GMO GTI-5813 developed by Associate Professor Searle and team was able to reduce disease and improve graft take, we could have the world's first effective biocontrol for crown gall disease in grapevines, a century old problem for vineyards."
Associate Professor Searle said results from the field trial would be collated after nine months.
