Sleuth scientist solves mystery of the mouldy mungbean

A Queensland Government researcher has cracked the case of a mouldy oldie that’s baffled scientists for decades.

Minister for Agricultural Industry Development and Fisheries Mark Furner said a Department of Agriculture and Fisheries plant pathologist has found that two pathogens cause powdery mildew in mungbean, potentially unlocking new solutions for the $100m Australian industry.

“Scientist Lisa Kelly has ‘bean’ on the case to unlock the mystery of the fungal disease that’s been present in Australian mungbean crops for at least 60 years,” Mr Furner said.

“We thought only one pathogen - Podosphaera xanthii - caused the powdery mildew until our Plant Pathologist confirmed a second culprit lurking in the paddocks of mungbean and black gram in Australia - Erysiphe vignae sp. nov..”

Minister Furner said the research finding paves the way to protect the mungbean industry which has an export value of more than $100 million to Australia in 2021.

“Powdery mildew has potential to cause more than 40 per cent yield losses in mungbean crops which is very costly to growers who are mainly based in Queensland and northern New South Wales,” Mr Furner said.

“Accurate identification of the causal species of powdery mildew will help Queensland growers better manage the risk of fungicide resistance, hopefully choose the best varieties to grow in the future and manage crop rotations to minimise the spread of the disease.

“Agriculture is an essential industry in Queensland and breakthroughs like this can only help this key pillar of Queensland’s COVID-19 Economic Recovery Plan.”

While Podosphaera xanthii is known to impact a range of crops, the newly-discovered Erysiphe vignae sp. nov has so far only been found on Australian crops of mungbean and black gram, which is a species of bean popular in northern India.

Despite this, it is likely the new pathogen can impact on other crops.

The Department’s Plant Pathologist collected mungbean plants infected with powdery mildew from growers’ paddocks and identified the pathogen species under the microscope and through DNA sequencing.

“It was surprising to find that mungbean is infected by two very different species of powdery mildew and that one was an undescribed species which we got to name ourselves,” Lisa Kelly said.

“This might help explain why powdery mildew is worse in some areas and seasons than others and scientists around the world who work on mungbean will be able to see whether the newly-discovered Erysiphe vignae also infects crops outside of Australia.

“Now that we know which species are causing the disease in Australia, we can develop strategies that will target these pathogens to better control the disease.

“We may find that host resistance or fungicide requirements differ between the two species. Host resistance and host range testing is underway currently, with results expected next year.”

The research has been published in the international journal Phytopathology. 

ENDS

Media contact:          Ron Goodman            0427 781 920