Abstract
Microscopic pores present in the epidermis of plant aerial organs, called stomata, allow gas exchanges between the inner photosynthetic tissue and the atmosphere. Regulation of stomatal aperture, preventing excess transpirational vapor loss, relies on turgor changes of two highly differentiated epidermal cells surrounding the pore, the guard cells. Increased guard cell turgor due to increased solute accumulation results in stomatal opening, whereas decreased guard cell turgor due to decreased solute accumulation results in stomatal closing. Here we provide direct evidence, based on reverse genetics approaches, that the Arabidopsis GORK Shaker gene encodes the major voltage-gated outwardly rectifying K(+) channel of the guard cell membrane. Expression of GORK dominant negative mutant polypeptides in transgenic Arabidopsis was found to strongly reduce outwardly rectifying K(+) channel activity in the guard cell membrane, and disruption of the GORK gene (T-DNA insertion knockout mutant) fully suppressed this activity. Bioassays on epidermal peels revealed that disruption of GORK activity resulted in impaired stomatal closure in response to darkness or the stress hormone abscisic acid [corrected]. Transpiration measurements on excised rosettes and intact plants (grown in hydroponic conditions or submitted to water stress) revealed that absence of GORK activity resulted in increased water consumption. The whole set of data indicates that GORK is likely to play a crucial role in adaptation to drought in fluctuating environments.
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Claims 7
Claim · model-written summary
GORK encodes the major outward rectifying potassium channel in Arabidopsis guard cells.
- Taxon
- Arabidopsis
Arabidopsise0 - Gene
- GORK Shaker genee0
- Outcome
- major voltage-gated outwardly rectifying K(+) channel of the guard cell membranee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the Arabidopsis GORK Shaker gene encodes the major voltage-gated outwardly rectifying K(+) channel of the guard cell membrane”
Claim · model-written summary
Dominant negative GORK polypeptides strongly reduced guard cell channel activity.
- Taxon
- ArabidopsisArabidopsise0
- Treatment
- Expression of GORK dominant negative mutant polypeptidese0
- Gene
- GORKe0
- Outcome
- outwardly rectifying K(+) channel activitye0
- Direction
- strongly reducee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of GORK dominant negative mutant polypeptides in transgenic Arabidopsis was found to strongly reduce outwardly rectifying K(+) channel activity in the guard cell membrane”
Claim · model-written summary
GORK gene disruption fully suppressed the channel activity.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- disruption of the GORK gene (T-DNA insertion knockout mutant)e0
- Gene
- GORK genee0
- Outcome
- this activitye0
- Direction
- fully suppressede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“disruption of the GORK gene (T-DNA insertion knockout mutant) fully suppressed this activity”
t0“Arabidopsis”
Claim · model-written summary
Disrupting GORK impaired stomatal closure in darkness.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- disruption of GORK activitye0
- Outcome
- stomatal closuree0
- Direction
- impairede0
- Qualifier
- darknesse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“disruption of GORK activity resulted in impaired stomatal closure in response to darkness or the stress hormone abscisic acid [corrected]”
t0“Arabidopsis”
Claim · model-written summary
Disrupting GORK impaired stomatal closure in response to abscisic acid.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- disruption of GORK activitye0
- Outcome
- stomatal closuree0
- Direction
- impairede0
- Qualifier
- abscisic acide0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“disruption of GORK activity resulted in impaired stomatal closure in response to darkness or the stress hormone abscisic acid [corrected]”
t0“Arabidopsis”
Claim · model-written summary
Absence of GORK activity increased water consumption.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- absence of GORK activitye0
- Outcome
- water consumptione0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“absence of GORK activity resulted in increased water consumption”
t0“Arabidopsis”
Claim · model-written summary
GORK is inferred to play a crucial role in drought adaptation.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- GORKe0
- Outcome
- adaptation to droughte0
- Qualifier
- likelye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“GORK is likely to play a crucial role in adaptation to drought in fluctuating environments”
t0“Arabidopsis”
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