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BACKGROUND: Currently many plants require high amounts
of added nitrate fertilizers for optimal growth. Plant growth is often limited
by the availability of soil nitrate, which is compensated for by the use of
nitrate-containing fertilizers. Such fertilizers have numerous and serious environmental
side effects, not to mention their occasional diversion by terrorists as a bomb
component. Diatom nitrate transporters have an unusually high affinity for nitrate,
which they concentrate from seawater (Dugdale, R.C. 1967. Limnol. Oceanog.
12:685; Eppley, et al., 1969. Limnol. Oceanog. 14:912).
By transgenic expression, plants that contain them have the potential for growing
on soil with lower nitrate levels.
DESCRIPTION: A cDNA clone encoding a nitrate transporter homolog
has been isolated from the diatom Cylindrotheca fusiformis. The gene
contains no introns, and so is well suited to expression in other organisms.
Constructs are made placing the cDNA clone under the control of plant root-specific
promoters. Plant growth can then be optimized for low nitrate soils.
ADVANTAGES: The advantages of this invention are that it could
reduce or eliminate the need for nitrate fertilizers in crop plants, resulting
in similar yield, but without the environmental contamination resulting from
high amounts of nitrate.
CASE NUMBER: SD98-083
INQUIRIES TO: invent@ucsd.edu
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