The world-first findings, published in The ISME Journal, show that – when infected by a ‘mycovirus’ (a virus that infects a fungus) – the fungus Sclerotinia was debilitated and therefore no longer a threat to crops.

The mycovirus-debilitated Sclerotinia readily grew as a beneficial ‘endophyte’ (harmless fungus) within plants of diverse cereal crops including wheat, rice, barley and maize. 

The study, led by Huazhong Agricultural University Professor Dahong Jiang, found that the beneficial endophyte effectively protected cereal plants against multiple fungal diseases and increased the growth and yield of crops in-field.

It reduced Fusarium Head Blight in wheat by up to 60 per cent in multiple field trials in China, and also provided effective protection against rice blast and wheat stripe rust diseases.

Sclerotinia is commonly regarded as a damaging pathogen (disease-causing fungus) of non-cereal crop plants in which it causes multimillion dollar losses worldwide every year.

Study co-researcher, UWA School of Agriculture and Environment and Institute of Agriculture Professor Martin Barbetti, said the discovery was “the silver bullet we have all been looking for”.

“Amazingly, the risk from virulent Sclerotinia was also simultaneously greatly reduced on normally susceptible non-cereal crops like canola,” Professor Barbetti said. 

“This is because the mycovirus in the debilitated Sclerotinia endophyte meant it was no longer able to cause serious disease in non-cereal crops.”

Professor Barbetti said there was now huge potential to exploit the same principle and discover new mycovirus-disabled fungal biocontrol agents to address other devastating crop-fungal disease combinations.

“Debilitated biocontrol agents like this can be applied as a beneficial seed treatment, while avoiding the risk of in-field release of virulent fungal pathogens,” he said.