New Gene May Simplify Breeding of Superior Spuds
By Marcia Wood
December 24, 1997
Tomorrow's potatoes may boast a wider array of prized traits like
disease and insect resistance, borrowed from their wild relatives.
That's because new genetic engineering research by scientists with the
Agricultural Research Service
should make it easier for breeders to sidestep a problem that often
frustrates their use of primitive potatoes.
The wild spuds, native to the Andes Mountains in South America, are
a crucial source of genes useful for developing new commercial
varieties with traits valuable to potato growers or processors. But
sometimes those wild potatoes contain high levels of unwanted, bitter
compounds called glycoalkaloids. So, when breeders cross a wild potato
with a commercial variety, they have to discard any offspring with a
high glycoalkaloid level. The high-glycoalkaloid offspring are
useless--no matter what valuable traits they also possess.
This problem could vanish in the future. ARS scientists recently
discovered a gene that, when re-worked, undermines production of an
enzyme without which potatoes can't make a key glycoalkaloid. The
thwarted enzyme is a tongue-twister known as solanidine UDP-glucose
glucosyltransferase. Potatoes need this enzyme in order to make a
glycoalkaloid called alpha-chaconine.
In laboratory and greenhouse investigations, experimental plants
containing the re-worked gene--inserted through biotechnology
methods--had lower levels of glycoalkaloids. Researchers are seeking a
patent for the new gene.
William R. Belknap of the ARS'
Research Center, Albany, Calif., leads the genetic engineering
The December issue of the agency's Agricultural Research magazine
has a story about the investigations. The story is also on the World
Wide Web at:
Scientific contact: William R. Belknap, ARS
Research Center, Albany, Calif., phone (510) 559-6072, fax (510)