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Virus-Resistant Plum Trees--Ready and Waiting
By Judy McBride
September 17, 2001
Three plum trees standing in
Agricultural Research Service orchards
could help prevent a nasty fruit virus from becoming established in the United
States as it is in Europe and elsewhere.
The trees--simply dubbed C5"--are virtually immune to all major
strains of plum pox virus. Also known as sharka, plum pox virus deforms or
blemishes plums, peaches, apricots and almonds, making the fruit unmarketable.
C5 was developed by ARS horticulturist Ralph Scorza. It looks very similar
to its female parent, Bluebyrd, a commercial cultivar developed by Scorza
through traditional breeding. And its fruit tastes the same. The difference is
that C5 was given a gene that prevents plum pox virus from multiplying.
First discovered in Adams County, Pa., nearly two years ago, plum pox
recently surfaced in two more Pennsylvania counties--York and Cumberland.
Fortunately, the Pennsylvania strain of the virus is less aggressive than other
strains found in Europe.
That could buy some time for the ARS-developed tree to reach the market.
Because C5 was genetically engineered, ARS technology transfer specialists
cant say when it will be available for commercial use. It will have to
pass a strict regulatory process for genetically modified organisms. Moreover,
the pieces of DNA, as well as the techniques required to make them work, are
all from different sources, and several are patented.
Thats why ARS filed a patent on C5 this month--to encourage a partner
to pull all these threads together toward commercialization, according to an
ARS patent advisor.
Michel Ravelonandro at INRA,
the French counterpart of ARS, provided the plum-pox- resistance gene. Dennis
Gonsalves at Cornell University in
Geneva, N.Y., provided a souped-up vector--an Agrobacterium--for
inserting the gene.
An article on ARS plum pox research is in the
issue of Agricultural
ARS is the U.S. Department of
Agricultures principal scientific research agency.