Kiwifruit detectives trace disease to China

US and Italian scientists have traced a bacterium that has been destroying kiwifruit in New Zealand and Europe back to China where they believe it originated, according to a study on Wednesday.

Since the disease known as "kiwifruit canker" emerged in Italy 2008, it has wiped out orchards mainly across Europe and South America and caused hundreds of million of dollars in losses, according to the article in the journal PLoS ONE.

The culprit is a bacterium, Pseudomonas syringae pv. actinidiae (Psa), which causes red or white slime to ooze from the plant's stems or branches, in some cases causing the plants to die.

A similar disease afflicted orchards in China and Japan in the 1980s, so scientists used the latest DNA sequencing technology to shed light on the pathogens to see if there were any links.

Virginia Tech associate professor Boris Vinatzer and Giorgio Balestra of the University of Tuscia in Italy sequenced the DNA of Psa bacteria from kiwifruit trees in China, Italy, New Zealand and Portugal.

They found that the bacteria from China, Europe, and New Zealand were almost identical, with one slight variation that in a single region of the DNA that linked the New Zealand outbreak to the Chinese bacteria.

Therefore, the study authors believe the bacterium was likely imported from China to Italy first, and later from China into New Zealand where the disease turned up in 2010.

"The first step in stopping the spread of aggressive bacteria like Psa is knowing where they come from and how they have spread," Balestra said.

"Now that we have sequenced the DNA and found its likely origin, we can start to figure out ways to stop it and similar bacteria from doing so much damage in the future."