Grains Research and Development

Date: 01.11.2001

Modified bacteria may take all

Take-all in wheat with weeds in foreground: bio-control promises a cheap and environmentally friendly alternative to fungicides.

A STRAIN of genetically modified bacteria is set to be trialed on a central New South Wales wheat farm later this year as a bio-control for the insidious fungal root disease take-all.

Bio-control promises a cheap and environmentally friendly alternative to rotations and grass weed control. Despite these current measures, take-all commonly reduces yields by 10 per cent.

The new improved Pseudomonas bacteria will be tes ted under controlled conditions on-farm for the first time as part of ongoing research funded by the Grain Growers Association and by growers and the Federal Government through the GRDC.

"Glass house trials have shown the modified bacteria's ability to suppress take-all and boost wheat yields by as much as 40 per cent," said Australian National University scientist Murali Nayudu.

"The glasshouse trials have been promising with the modified strains generally doing better than the parent strain."

Large-scale field trials showed that the unmodified bacteria, or parent strain, controlled take-all and increased wheat yields by 20 to 25 per cent, reported Dr Nayudu.

"Pseudomonas bacteria build up on wheat roots and then produce an anti-fungal agent that kills the take-all ," said Dr Nayudu.

"What we have been aiming to do through genetic modification is produce strains with even greater ability to produce the anti-fungal agent and control take-all."

The research is developing a method to introduce the bacteria by coating the seed at the time of planting. One of the aspects that Dr Nayudu hopes to improve is the bacteria's ability to withstand very dry years, a key to long-term bio-control.

Program 2.6.2 Contact: Dr Murali Nayudu 02 6125 3643