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STRENGTH AND WIND RESISTANCE IN RICE
BACKGROUND: Silicon is regarded as
an essential trace mineral nutrient for optimum health
of both plant and animal species, however, the biochemistry
and mechanism of the silicon requirement is not understood.
In grass-related plants such as rice, wheat and other
commercially important crops, silicon deficiency in
soil and plant tissues results in weakened mechanical
strength and poor wind resistance. In rice, silicon
is thought to associate with stem structural polysaccharides
to produce specialized cross-links. Si-deficient soils
can not be effectively fertilized, and (in the case
of rice) re-flooding has been tried as a means of liberating
additional Si (as silicate). Conventional plant breeding
has not resulted in a solution to the wind resistance
problem associated with silicon-poor soils.
DESCRIPTION: The current invention,
based on the first report and characterization of a
specific, biological transporter protein for silicon
(see attached NATURE article), provides a means of transgenically
enhancing silicon nutrition in rice and other vulnerable
grasses via overexpression of an imported Si-transporter
gene in root structures. A suitable constitutive promoter
controlling expression of the Si-transporter protein
in inserted into rice or wheat via conventional transformation
techniques, and the resulting transgenic plant is able
to concentrate silicon (as silicate) more effectively
from Si-poor environments. The technique has been used
effectively to generate commercially useful plant species
concentrating K+ from a high NaCl saline environment
or heavy metals of interest for bioremediation purposes
(currently licensed UCSD inventions SD93-394 and SD96-102,
respectively).
ADVANTAGES: The invention allows for
the first time a practical means of enhancing rice cultivation
in silicon-poor soils without the use of wasteful re-flooding
practices. It represents the first known isolation
and cloning of a biological silicon nutritional transporter.
CASE NUMBER: SD98-061
INQUIRIES TO: invent@ucsd.edu
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