Natural seed coating wins Eureka Prize

Australian graingrowers may soon have a double-barrel weapon in the fight against fungal diseases - a natural seed coating that protects a developing plant against fungal disease and boosts growth at the same time.

Professor Chris Franco, who leads the research group from Flinders University in Adelaide and CSIRO Plant Industry in Perth that developed the microbial system, has received the $10,000 GRDC-sponsored Eureka Prize for "Research to Improve the Environmental Sustainability of Graingrowing".

The coating is formed from spores of naturally occurring microbes called filamentous actinobacteria, which produce compounds that discourage fungal growth while at the same time encouraging plant growth. The seed coating is an entirely natural product which expands its coverage as the plant grows.

The bacteria can increase grain yields by up to 60 percent in soils affected by fungal diseases such as take-all, rhizoctonia and fusarium.

Professor Franco says his team knew that actinobacteria could produce a range of chemical structures, including antibiotics.

"We started looking for new sources of these microbes and found them inside native Australian plants," he says. If the bacteria were able to live symbiotically inside plant tissues, he reasoned, they had to be doing something useful for the plant. In 1998, he and PhD student Justin Coombs began to further investigate the action of these microbes.

After years of painstaking work, the research team found that the bacteria did indeed help control the fungal rot disease. But also, quite independently, it boosted growth in the plants it inhabited. "They offer a natural, sustainable alternative to the use of chemicals - and because they live in and colonise plant tissue, they only have to be applied once," says Professor Franco.

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GRDC Research Code: UF 00002, program 3