The bacterial disease that has blighted New Zealand kiwifruit
orchards originated in China and was also responsible for an
outbreak in Italy and Chile, new research has shown.
Kiwifruit canker, or Psa, has spread to more than 1000 New
Zealand orchards since it was discovered in the Bay of Plenty
region in November 2010.
Combating the disease was expected to cost between $310
million and $410 million over the next four years - with the
long term bill rising to between $740 million and $885
Scientists from the University of Otago's department of
biochemistry today published evidence that the virus began
its journey in China, before travelling to Italy in 2008 and
Chile and here in 2010.
This result would help clarify the pathway by which Psa
entered New Zealand, researchers Associate Professor Russell
Poulter, Professor Iain Lamont and Dr Margi Butler said.
Their research, which involved DNA detective work using
advanced genomics technology, appeared today in the
international journal PLOS ONE.
To analyse the geographic origin of Psa the researchers
sequenced and compared the genomes of Psa strains from Japan,
Chile, China, Italy and New Zealand.
Dr Poulter said the team found the core genomes of the
Chinese, Chilean, Italian and New Zealand strains were almost
identical and likely shared a common ancestor around 10-15
However the genome sequence demonstrates that the New Zealand
strains are a distinct clone. The Italian strains form
another geographical clone.
"These findings paint a clear picture of an independent
Chinese origin for both the Italian and the New Zealand
outbreaks and suggest the Chilean strains also come from
China, Dr Poulter said.
- Rebecca Quilliam of APNZ