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Method for Facilitating Commercial Cultivation in High-Saline
Environments
BACKGROUND: Potassium is the major
cationic nutrient required for the commercial cultivation
of plants, and is a main component (potash) of crop
fertilizers used worldwide. Further, Na+ competes for
K+ transport in plants, and annual crop losses due to
NaCl stress in soils contaminated by use of high-salinity
irrigation water are over $200 million in California's
Imperial Valley alone. Salt invasion of croplands worldwide
is well-recognized as a growing threat to the worldwide
food supply, with total annual production losses ranging
from 30-60%.
DESCRIPTION: Researchers at UCSD have
been the first to isolate and characterize a novel gene
coding for the high-affinity potassium transporter protein
from plant cells that is responsible for nutritional
uptake of potassium from the environment. The HKT1 gene
encodes a membrane high-affinity K+ transport system.
Transgenic plants designed to overexpress this gene
have greatly enhanced ability to pump K+ from low potassium
soils and especially from high sodium soils. This capability
could especially benefit Third World countries.
ADVANTAGES: Genetic manipulation of
plants through incorporation of this gene has the potential
to greatly enhance growth rate on low-potassium soils
while allowing a reduction in the use of costly fertilizers.
Equally important, these transgenic plants have been
shown to possess a enhanced ability to grow on soils
with high levels of NaCl contamination. This is made
possible by the very high density of K+ transporters,
permitting more effective uptake of potassium ions in
preference to transporter competition by the high environmental
sodium. Genetic manipulation of the HKT1 gene may provide
for further K+/Na+ selectivity.
CASE NUMBER: UC93-394
INQUIRIES TO: invent@ucsd.edu
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