Microscopic soil-dwelling actinobacteria are showing promise as biocontrol agents for wheat and canola diseases.
Microscopic soil bacteria with anti-fungal properties are being put to the test as potential biocontrol agents in the war against some of the most costly diseases affecting WA wheat and canola crops.
Researchers from CSIRO Agriculture have identified strains of soil-dwelling actinobacteria that appear to be effective at suppressing a range of fungal pathogens of wheat and canola.
These actinobacteria include antagonists against the diseases Fusarium crown rot, Pythium damping off, take-all root rot, Rhizoctonia hypocotyl rot and Sclerotinia stem rot that are estimated to cost the Australian grains and oilseed industries more than $250 million annually in lost production and control measures.
CSIRO Agriculture research scientist Dr Margaret Roper will outline the organisation’s major breakthroughs in investigations into actinobacteria at the upcoming Grains Research and Development Corporation’s (GRDC) Grains Research Update, Perth.
This event is being held at the Perth Convention and Exhibition Centre on February 29 and March 1 and registrations can be made here.
Dr Roper’s presentation to the Perth Update will outline the huge potential for development of actinobacteria as biocontrol agents that could be used as seed coats or foliar sprays on wheat and canola.
She said the exciting part of this research was that the promising isolates of the actinobacteria were discovered - already thriving - in WA soils on roots of wheat plants that were performing well in the face of high fungal disease pressure.
“This means they are already adapted to local conditions and we are also finding they readily take up residence in crop roots and are easy to culture and grow,” she said.
From about 300 isolates selected by the researchers, a small group of the bacteria was found to effectively suppress a range of soil and stubble-borne fungal disease pathogens in the laboratory.
Dr Roper said testing on small wheat plants in a glasshouse also identified two isolates that could reduce fungal disease levels by 75-94 per cent, but further testing of plants grown to maturity - both in the glasshouse and in the field - was required.
She said, if successful in the paddock, the use of actinobacteria as biological control agents applied as a seed coat might become an integral part of integrated fungal disease management in WA in the future.
“This might also provide a quicker solution to combatting disease than breeding disease-resistant wheat and canola varieties,” she said.
“The incidence of some fungal diseases is rapidly increasing in WA, especially Fusarium crown rot of wheat and Sclerotinia stem rot of canola.
“With no - or limited - host plant resistance available and disease management strategies difficult to implement, novel and broad-spectrum control approaches are needed.
“To date, fungicides used as seed dressings and foliar sprays provide variable protection depending on the pathogen and timing of application.
“And in WA, pathogens can grow and survive in stubble or on the roots of summer weeds and act as a source of infection in the following crop.”
Dr Roper said to be considered successful, any potential actinobacteria biocontrol agents must suppress the fungal disease effectively, survive either in the plant tissues or within the rhizoplane of growing plants and be easy to culture and inoculate on to plants to allow for realistic application methods in the field.
Dr Margaret Roper, CSIRO
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