post-doctoral position in potassium transport

Jason Reed jreed at
Wed Feb 16 13:46:05 EST 2000

The role of potassium transport in Arabidopsis development.
         A post-doctoral position is available to study potassium ion
movements in Arabidopsis using a mutant with a defect in a potassium
transporter.  The shy3-1 mutant has a short hypocotyl and abnormally small
cells in the stem and leaves (1,5).  SHY3 encodes AtKUP2, a member of the
KUP family of potassium transporter proteins (2-4).  This is the first
mutation in a member of this gene family in Arabidopsis, and it provides a
unique tool to study the role of potassium transport in Arabidopsis
development.  Potassium is the principal cation in plants responsible for
the osmotic potential that drives cell growth.  The phenotypes of the
shy3-1 mutant probably arise from a decrease in K+ delivery to the shoot,
although the primary defect in the mutant could either be in K+ uptake into
the root or in unloading K+ from vasculature or apoplastic space into shoot
cells.  The shoot cells in the mutant are small even in the presence of
abundant external K+.  The duties of the position would be to address the
role of SHY3/AtKUP2 in delivery of potassium to the shoot, using several
approaches.  These could include i) determining which cells express the
gene using promoter-reporter fusions and in situ hybridization; ii)
examining the subcellular localization of SHY3/AtKUP2 protein, using
protein fusions and immunocytochemistry; and iii) assessing where the block
in ion transport in the mutant occurs, by monitoring kinetics of Rb+
accumulation in different cell types of wild-type and mutant plants (using
radioactive 86Rb+ tracer as well as non-radioactive Rb+ and EXPMA (X-ray
probe microanalysis) imaging).  Experience with biochemistry, microscopy,
or molecular techniques would be useful.  For further information, contact
Jason Reed at the address below.  If interested, please send a current cv
and names of three references to the same address.

Jason W. Reed
Department of Biology
University of North Carolina at Chapel Hill
CB #3280, Coker Hall
Chapel Hill, NC 27599-3280
telephone: (919) 962-5699
FAX: (919) 962-1625
email: jreed at

1) Elumalai RP, Nagpal P, Reed JW  A potassium transporter needed for plant
shoot growth.  In preparation.
2) Fu H-H, Luan S (1998) AtKUP1: a dual-affinity K+ transporter from
Arabidopsis.  Plant Cell 10: 63-73.
3) Kim EJ, Kwak JM, Uozumi N, Schroeder JI (1998) AtKUP1: an Arabidopsis
gene encoding high-affinity potassium transport activity.  Plant Cell 10:
4) Quintero FJ, Blatt MR (1997) A new family of K+ transporters from
Arabidopsis that are conserved across phyla.  FEBS Letters 415: 206-211.
5) Reed JW, Elumalai RP, Chory J (1998) Suppressors of an Arabidopsis
thaliana phyB mutation identify genes that control light signalling and
hypocotyl elongation.  Genetics 148: 1295-1310.

Jason W. Reed
University of North Carolina
Department of Biology
CB #3280, Coker Hall
Chapel Hill, NC 27599-3280

telephone: 919-962-5699 (office)
            919-962-2161 (lab)
FAX: 919-962-1625
email: jreed at


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