KAT1 is not essential for stomatal opening.
It is generally accepted that K(+) uptake into guard cells via inward-rectifying K(+) channels is required for stomatal opening. To test whether the guard cell K(+) channel KAT1 is essential for stomatal opening, a knockout mutant, KAT1En-1, was isolated from an En-1 mutagenized Arabidopsis thaliana population. Stomatal action and K(+) uptake, however, were not impaired in KAT1-deficient plants. Reverse transcription-PCR experiments with isolated guard cell protoplasts showed that in addition to KAT1, the K(+) channels AKT1, AKT2/3, AtKC1, and KAT2 were expressed in this cell type. In impalement measurements, intact guard cells exhibited inward-rectifying K(+) currents across the plasma membrane of both wild-type and KAT1En-1 plants. This study demonstrates that multiple K(+) channel transcripts exist in guard cells and that KAT1 is not essential for stomatal action.
Max-Delbrück-Laboratorium, Carl-von-Linné-Weg 10, 50829 Cologne, Germany.
A
A
Szyroki
N
N
Ivashikina
P
P
Dietrich
M R
MR
Roelfsema
P
P
Ache
B
B
Reintanz
R
R
Deeken
M
M
Godde
H
H
Felle
R
R
Steinmeyer
K
K
Palme
R
R
Hedrich
D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D017931:DNA Primers; D004251:DNA Transposable Elements; D009154:Mutation; D018408:Patch-Clamp Techniques; D010940:Plant Proteins; D015221:Potassium Channels / Q000235:genetics / Q000502:physiology*; D024661:Potassium Channels, Inwardly Rectifying
D029681:Arabidopsis Proteins; D017931:DNA Primers; D004251:DNA Transposable Elements; C501210:KAT1 protein, Arabidopsis; D010940:Plant Proteins; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying