Plant 'Vaccination': new weapon against virus diseases by Alex Nicol

Dr Peter Waterhouse and Dr Ming Bo Wang examine the Golden Promise barley plant which has been 'vaccinated' against barley yellow dwarf virus (BYDV).

A TEAM of CSIRO researchers has developed a technique that holds out the promise of vaccinating crop plants against virus diseases. The technique has already been tested and proved with barley yellow dwarf virus and with potato virus Y.

Peter Waterhouse, who led the team at CSIRO Plant Industry, says that while the technique is virus-specific, there is no reason why it couldn't be used to produce 'one-shot' multiple vaccinations to protect a crop plant against all of its known virus diseases.

The technique is described as 'vaccination' because of the parallels between it and the vaccination techniques used to inoculate humans and animals against disease, but there's an important difference. The immunity derived from the vaccination of plants is

passed on to succeeding generations. The process promises to be a boon to plant breeders who in a number of cases are denied easy access to virus-resistant genes. This technology promises durable protection to their new cultivars.

As in the case of animals, the vaccination process makes use of the crop plant's natural defence mechanism. Dr Waterhouse explains that when a virus invades a plant, the host's immediate reaction is to attack it. The virus, however, manufactures a protein designed to shut down the host's defences.

" It's like a battle zone," he says. "And as in any war, the one there first with the most firepower wins. This 'vaccination' technique gives the host plant advance warning of what the virus looks like and the chance to land the first blow."

The vaccination is achieved by introducing some of the host plant's DNA that has been genetically modified to include a small piece of the virus gene, enough to allow the plant to 'recognise' the virus and to react to any future invasion.

Dr Waterhouse says that one of the real concerns that many people have with genetic modification is the possibility of introducing protein-producing genes that may trigger severe allergic reactions.

"Since we're not introducing any new protein but simply triggering a naturally occurring defence mechanism with a small piece of RNA, this isn't an issue," he says.

Depending on the acceptance of the technology, 'vaccinated' plants could be available to plant breeders within five years.

Program 1.3.1 Contact: Dr Peter Waterhouse 02 6246 5365; Dr David Abbott 02 6246 5360