Scientists close to releasing Psa findings
New Zealand scientists investigating a virulent strain of a kiwifruit disease are months away from releasing results that could have implications for growers worldwide.
Massey's professor of evolutionary genetics Paul Rainey said the team's findings about the source, virulence and evolution of Pseudomonas syringae pv. actinidiae (Psa) could inform development of disease-resistant kiwifruit.
"At this stage we cannot assert where the source of New Zealand's strain has come from," Prof Rainey said.
"Something has happened in 2008 in the outbreak in Italy that has then gone around the world. That has happened to give rise to an extremely pathogenic virulence. If we can understand that, we probably have the basis for breeding plant resistance."
Psa is ravaging North Island orchards, particularly in Bay of Plenty, spreading to Hawke's Bay just last week. The disease - which causes cankers on the fruit, leaf spots and plant death - is estimated to have cost the New Zealand kiwifruit industry about $800 million in lost earnings and jobs since 2010.
Massey University researchers have been working with the Plant and Food Research Institute on plant genome sequencing, looking at DNA of infected plants to discover how the bacterium takes residence in its host and where it came from.
Researcher Honour McCann presented some of the findings at the Infectious Disease Research Centre's first science symposium, which began in Palmerston North yesterday.
Understanding how the well-armed bacterium attacks its host is vital to the research, Ms McCann said.
Researchers view the co-evolution process like a plant "Cold War", she said.
Psa is constantly upgrading its artillery of bullets to outwit kiwifruits' evolving defence.
"We call it an arms race dynamic, for that reason," she said. "It evolves a body of armour to deflect the pathogens."
Within two months the team will present its findings on the evolution of the emerging infectious disease, Prof Rainey said.
- © Fairfax NZ News
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