Glutamate signalling and root development in Arabidopsis |
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P.
Walch-Liu*, T. Remans and B. G. Forde |
Dept. of Biological Sciences, Lancaster University,
Lancaster LA1 4YQ, UK |
*email:
p.walch-liu@lancaster.ac.uk
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Like the rest of the plant, the root system has no
pre-defined body plan, rather its development is continuously modified by interactions with environmental
factors, including nutrients. Plants are known to forage for localised supplies of nitrate by proliferating
their lateral roots within nitrate-rich patches. Recent evidence suggests that roots are also capable of
sensing and responding in a highly specific manner to the presence of organic N in the soil.
Arabidopsis root growth is very sensitive to the presence of external glutamate, but not to most
other amino acids. The ability to sense glutamate appears to reside in the root tip itself and is common to
both primary and lateral roots. Different ecotypes of Arabidopsis differ markedly in their glutamate
sensitivity and we have used recombinant inbred lines to map a major QTL for glutamate sensitivity to
chromosome 5. We will discuss our current understanding of the genetic and physiological basis of this
phenomenon and its possible relationship to the existence of a family of glutamate receptor genes in
plants. |