Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search

 


Otago research confirms Chinese origin of NZ’s PSA outbreak


Otago research confirms Chinese origin of NZ’s PSA outbreak


University of Otago scientists have today published persuasive evidence that the PSA strains responsible for the outbreak in North Island kiwifruit orchards came directly from China, as did those responsible for the 2008 Italian and 2010 Chilean outbreaks of the devastating canker disease. This result will help clarify the pathway by which PSA entered New Zealand.

Associate Professor Russell Poulter, Professor Iain Lamont and Dr Margi Butler, all from the University’s Department of Biochemistry, had been working with the New Zealand kiwifruit industry since mid-2011. The PSA (Pseudomonas syringae pv. actinidiae) bacterium was first detected in a Te Puke orchard in November 2010.

Their research, which involved DNA detective work using advanced genomics technology, appears today in the leading international journal PLOS ONE.

To analyse the geographic origin of PSA the researchers completely sequenced and compared the genomes of PSA strains from Japan, Chile, China, Italy and New Zealand. The analysis also used sequences present in public databases. The new sequences, which have been added to the public database GenBank, are the first New Zealand and Chilean PSA strains to be sequenced.

Dr Poulter says the team found that the core genomes of the Chinese, Chilean, Italian and New Zealand strains were almost identical and likely shared a common ancestor around 10-15 years ago. 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,” says Dr Poulter.

The researchers are now sequencing a further 20 strains, mostly from China but also Korean and Turkish strains. The researchers are focusing particularly on a type of mobile element they have detected in the PSA genome. These mobile genetic elements (termed ICE or ‘integrative conjugative elements’) can transfer between cells of different bacteria strains and alter properties such as their infectiousness and resistance to antibiotics.

Three distinct ICEs were identified by the team. The first was shared by the New Zealand strains and three strains from China. Another ICE was shared by Italian strains and a Chinese strain, while a third ICE was found in the Chilean strains.

“Some PSA may be inherently more virulent due to the particular ICE they carry. This has worrying implications as strains of kiwifruit that are resistant to one type of PSA might not be resistant to another. This means strict border control by kiwifruit-producing countries is more important than ever,” says Dr Poulter.

The genome sequencing was made possible by New Zealand Genomics Limited’s (NZGL) multi-million dollar Illumina HiSeq sequencing service. NZGL is a government-funded initiative involving a collaborative infrastructure of genetic sequencing technology and expertise, involving Auckland, Massey and Otago universities.
www.nzgenomics.co.nz/

Publication details:

Pseudomonas syringae pv. actinidiae from Recent Outbreaks of Kiwifruit Bacterial Canker Belong to Different Clones that Originated in China.
Margi I. Butler, Peter A. Stockwell, Michael A. Black, Robert C. Day, Iain L. Lamont, Russell T. M. Poulter

Once the embargo has lifted, the paper will be open access at this URL: http://dx.plos.org/10.1371/journal.pone.0057464


© Scoop Media

 
 
 
 
 
Business Headlines | Sci-Tech Headlines

 

Post-Post: Brian Roche To Step Down As NZ Post CEO

Brian Roche will step down as chief executive of New Zealand Post in April 2017, having led the state-owned postal service's drive to adjust to shrinking mail volumes with a combination of cost cuts, asset sales, modernisation and expansion of new businesses. More>>

ALSO:

Company Results: Air NZ Rides The Tourism Boom With Record Full-Year Earnings

Air New Zealand has ridden the tourism boom and staved off increased competition to deliver the best full-year earnings in its 76-year history. More>>

ALSO:

New PGP: Sheep Milk Industry Gets $12.6M Crown Funding

The Sheep - Horizon Three programme aims to develop "a market driven, end-to-end value chain generating annual revenues of between $200 million and $700 million by 2030," according to a joint statement. More>>

ALSO:

Half Full: Fonterra Raises Forecast Milk Price

Fonterra Co-operative Group Limited today increased its 2016/17 forecast Farmgate Milk Price by 50 cents to $4.75 per kgMS. When combined with the forecast earnings per share range for the 2017 financial year of 50 to 60 cents, the total payout available to farmers in the current season is forecast to be $5.25 to $5.35 before retentions. More>>

ALSO:

Keep Digging: Seabed Ironsands Miner TransTasman Tries Again

The first company to attempt to gain a resource consent to mine ironsands from the ocean floor in New Zealand's Exclusive Economic Zone has lodged a new application containing fresh scientific and other evidence it hopes will persuade regulators after their initial application was turned down in 2014. More>>

Wool Pulled: Duvets Sold As ‘Premium Alpaca’ Mostly Sheep’s Wool

Rotorua business Budge Collection Limited (Budge) and sole director, Sun Dong Kim, were convicted and fined a total of $71,250 in Auckland District Court after each pleading guilty to four charges of misrepresenting how much alpaca fibre was in their duvets. More>>

Get More From Scoop

 
 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news