Tackling Heterodera Australis in Australian cereals
Project name
“Nematode diagnostics across industries through capability succession, enhancement of collections and protocol development”
Part of project: Boosting Diagnostics for Plant Production Industries
GRDC code
BIO2004-001RTX (project number: 9177857)
What’s in a name?
Heterodera australis (Australian cereal cyst nematode; CCN), a nematode that specifically targets cereals and grasses, has posed significant challenges to Australian agriculture since the 1930s by causing substantial yield losses in infested paddocks.
Until 2024, the nematode identified as CCN in Australia was thought to be Heterodera avenae, the same species found in many grain-growing countries across Australasia, Europe, Africa and North America.
Heterodera australis was originally identified in Australia in 2002 using molecular techniques as a distinct cereal cyst nematode species, but morphological assessments and pathogenicity testing were not included in the research.
Due to this, the findings were not generally accepted by the Australian scientific community, but speculation on the correct identification of CCN and its potential differences in pathogenicity and yield loss continued.
In 2020, the project Rural R&D For Profit – Boosting Diagnostic Capacity for Plant Production Industries was established by the CSIRO in Canberra, with support from the Grains Research and Development Corporation (GRDC) and led by Dr Daniel Huston.
With the aid of fellow nematologists and researchers across Australia, Dr Huston collected soil samples from cropping paddocks to extract and identify cyst nematodes.
He sequenced cysts, conducted morphological identifications and tested the pathogenicity of Australian CCN and other cyst nematodes.
The results from the project confirmed that all locations in Australia have H. australis, both morphologically and molecularly.
This was significant, as Heterodera avenae has not been found anywhere in Australia and it’s been concluded that it never was. Therefore, this species has now been added to Western Australia's biosecurity documents as 'not present in Australia,' by DPIRD’s Biosecurity team led by Margaret Uloth.
Research methodology and findings
In a comprehensive study conducted from 2020 to 2023, involving collaborators from the Department of Primary Industries and Regional Development (DPIRD), researchers collected soil samples from various cereal-growing regions across Australia for analysis by the CSIRO team.
Using molecular barcoding techniques, Dr Huston identified Heterodera species present, including H. australis in 17 South Australian localities, one Victorian locality, and 10 Western Australian localities.
Economic impact and management
Before the development of resistant cereal strains, H. australis caused significant economic losses in Australia's cereal production. CCN still causes significant yield losses in infested paddocks where susceptible cereal varieties are grown. In Western Australia, CCN is found in pockets of the Avon Valley, Esperance, Albany and in our more northern growing areas from Yerecoin and Moora to Geraldton. Information on suitable variety choices in infested paddocks are updated annually in DPIRD’s Crop sowing guide
DPIRD Research Scientist Sarah Collins said researchers concluded Heterodera australis is an acceptable taxonomic name for the Australian cereal cyst nematode and is the only CCN species parasitising cereals in Australia at present.
"We also conclude that H. australis is not native to Australia and was most likely introduced from China in the 1850s, rather than from Europe as previously assumed," she said.
Understanding the nematode's origins, backed by molecular, morphological and pathogenicity data, aids in designing biosecurity measures to prevent its spread and potentially forecasting future invasions.
Future directions
The ongoing management of H. australis remains a high priority, as does the need for continued efforts in breeding resistant cereal varieties and adapting to changes in the pest's behaviour or biology.
This proactive approach will help mitigate future invasions and ensure sustainable cereal production in Australia.
Funding partners/project collaborators
Australian National Insect Collection, National Research Collections Australia, CSIRO
Plant and Soil Health, South Australian Research and Development Institute
AgriBio, Centre for AgriBioscience, Agriculture Victoria Research
Department of Energy, Environment and Climate Action (DEECA)
School of Applied Systems Biology, La Trobe University
More information
Click here to read the full paper DNA barcoding of Australian cereal cyst nematode populations with comments on likely origin and taxonomy (Tylenchoidea: Heterodera)
Click here to read Detection of heterodera mani in Western Australia by D. C. Huston, M. Hodda, A. Hills and S. Collins
Australasian Plant Disease Notes 2023 Vol. 18 Issue 1 Pages 18
Contact
Sarah Collins
DPIRD Senior Research Scientist
E: Sarah.Collins@dpird.wa.gov.au
P: (08) 9368 3612