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A new papaya, genetically resistant to papaya ringspot virus (PRSV), has
rescued the Hawaiian papaya industry and may have the potential to do the
same in other papaya-growing regions of the world, say plant pathologists
with The American Phytopathological Society (APS) August 2004.


"In 1992, Hawaii's papaya industry faced economic disaster when PRSV was
discovered in the Puna District of the Hawaii Island where 95 percent of the
state's papaya was grown," said Dennis Gonsalves, plant pathologist with the
USDA's Agricultural Research Service at the U.S. Pacific Basin Agricultural
Research Center, Hilo, HI.

By 1995, PRSV was widespread in Puna and the industry was in a crisis
situation. PRSV rapidly spreads when aphids (small insects) pick up the
virus on their mouths while feeding on infected plants and continue to feed
on healthy plants.

In the late 1980s, plant pathologists began to develop transgenic papayas
resistant to PRSV and the disease-resistant papaya was commercially released
in May 1998.

"Today, we are proud to say that the transgenic papaya has fulfilled the
hope of the Hawaiian papaya industry to control PRSV and to restore the
supply of papaya to nearly the level existing before PRSV entered Puna in
1992," said Gonsalves. The resistance of the transgenic papaya allowed
farmers to directly reclaim their farms without first clearing their land of
all infected papaya trees. The percentage of Hawaii's fresh papaya
production produced in Puna has risen from a low of 65 percent in 1999 to 84
percent in 2002.

Since PRSV is a worldwide problem on papaya, other countries have showed
interest in developing the technology for their use. "Due to its success,
the transgenic papaya has often been referred to as the model for the use of
biotechnology to help agriculture," said Gonsalves.

[www.medicalnewstoday.com]

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