WA researchers developing virus-resistant legumes

Scientists at the Centre for Legumes in a Mediterranean Climate (CLIMA) in Western Australia are using transgenic techniques to develop new varieties of legumes with resistance to viruses.

Cucumber Mosaic Virus (CMV) affects almost 200 species of plants worldwide, according to Dr Stephen Wylie, a senior research scientist involved in the project, known as the Transgenic Pulse Development Project.

In Western Australia, it is a major threat to the lupin crop as well as the high-value chickpea crop, which can lose up to 70 per cent of its yield due to CMV in a bad year.

Wylie and his colleagues are using a method developed by researchers for creating Barley Yellow Dwarf Virus resistant strains of wheat and barley, as well as potato leaf roll virus resistant potatoes.

The technique involves introduction of a small piece of the CMV virus into the plant so that it is expressed as a hairpin loop of double-stranded RNA.

According to Wylie, the plant cell then attacks the RNA and destroys it. This primes the plant to recognise the sequence and when exposed to the virus, the plant will degrade it before it can multiply.

The introduced DNA is also passed down to subsequent generations as a transgene.

At present, the team has third generation glasshouse plants containing the CMV transgene. Wylie said that they hope to start experiments to challenge the plants with virus later this year.

Ultimately, the group would like to perform field trials on the varieties they develop, before commercialising the new strains.

The approach has an advantage in that the DNA introduced to the plants is never expressed as a protein by the plant, only as RNA, explained Wylie.

"The genes we are using are already present in many vegetables that we eat every day," he claimed, explaining that vegetables are commonly infected by the viruses.

The team also plans to remove selectable markers from the transgenes.

"We are trying to address some of the concerns that the anti-GM lobby has," Wylie said.

He added that, unlike cereal crops, legumes are not cross-pollinating species, and thus spread of the transgene to other plants is unlikely.

CLIMA is an organisation involving the University of Western Australia, Murdoch University, Agriculture Western Australia and CSIRO Plant Industry. The Transgenic Pulse Development Project is fully funded by the Grains Research and Development Corporation.