Transgenic Plants Incorporating a High-Affinity Potassium Nutrition Transporter

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%.

Technology 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: SD1993-394

Inquiries To: invent@ucsd.edu