Abstract
SUMMARY: Light-induced stomatal opening in C3 and C4 plants is mediated by two signalling pathways. One pathway is specific for blue light and involves phototropins, while the second pathway depends on photosyntheticaly active radiation (PAR). Here, the role of NtMPK4 in light-induced stomatal opening was studied, as silencing of this MAP kinase stimulates stomatal opening. Stomata of NtMPK4-silenced plants do not close in elevated atmospheric CO(2), and show a reduced response to PAR. However, stomatal closure can still be induced by abscisic acid. Measurements using multi-barrelled intracellular micro-electrodes showed that CO(2) activates plasma membrane anion channels in wild-type Nicotiana tabacum guard cells, but not in NtMPK4-silenced cells. Anion channels were also activated in wild-type guard cells after switching off PAR. In approximately half of these cells, activation of anion channels was accompanied by an increase in the cytosolic free Ca(2+) concentration. The activity of anion channels was higher in cells showing a parallel increase in cytosolic Ca(2+) than in those with steady Ca(2+) levels. Both the darkness-induced anion channel activation and Ca(2+) signals were repressed in NtMPK4-silenced guard cells. These data show that CO(2) and darkness can activate anion channels in a Ca(2+)-independent manner, but the anion channel activity is enhanced by parallel increases in the cytosolic Ca(2+) concentration. NtMPK4 plays an essential role in CO(2)- and darkness-induced activation of guard-cell anion channels, through Ca(2+)-independent as well as Ca(2+)-dependent signalling pathways.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 9
Claim · model-written summary
NtMPK4 silencing stimulated stomatal opening.
- Taxon
- Nicotiana tabacum
Nicotiana tabacumt0 - Treatment
- silencing of this MAP kinasee0
- Gene
- NtMPK4t0
- Outcome
- stomatal openinge0
- Direction
- stimulatese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“silencing of this MAP kinase stimulates stomatal opening”
t0“NtMPK4 impairs CO2‐induced stomatal closure, activation of anion channels and cytosolic Ca2+signals in Nicotiana tabacum guard cells”
Claim · model-written summary
Stomata of NtMPK4-silenced plants failed to close under elevated CO2.
- Taxon
- Nicotiana tabacumNicotiana tabacumt0
- Treatment
- NtMPK4-silencede0
- Gene
- NtMPK4e0
- Outcome
- Stomatae0
- Direction
- do not closee0
- Qualifier
- elevated atmospheric CO(2)e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Stomata of NtMPK4-silenced plants do not close in elevated atmospheric CO(2)”
t0“Nicotiana tabacum”
Claim · model-written summary
NtMPK4-silenced stomata showed a reduced PAR response.
- Taxon
- Nicotiana tabacumNicotiana tabacumt0
- Treatment
- NtMPK4-silencede0
- Outcome
- response to PARe0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Stomata of NtMPK4-silenced plants do not close in elevated atmospheric CO(2), and show a reduced response to PAR”
t0“Nicotiana tabacum”
Claim · model-written summary
Abscisic acid still induced stomatal closure in NtMPK4-silenced plants.
- Taxon
- Nicotiana tabacumNicotiana tabacumt1
- Treatment
- abscisic acide0
- Outcome
- stomatal closuree0
- Direction
- inducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“stomatal closure can still be induced by abscisic acid”
t1“Nicotiana tabacum”
Claim · model-written summary
CO2 activated anion channels in wild-type guard cells but not NtMPK4-silenced cells.
- Taxon
- Nicotiana tabacumNicotiana tabacume0
- Treatment
- CO(2)e0
- Outcome
- plasma membrane anion channelse0
- Direction
- activatese0
- Comparator
- NtMPK4-silenced cellse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CO(2) activates plasma membrane anion channels in wild-type Nicotiana tabacum guard cells, but not in NtMPK4-silenced cells”
Claim · model-written summary
Switching off PAR activated anion channels in wild-type guard cells.
Not reportedTaxon
Verbatim
e0“Anion channels were also activated in wild-type guard cells after switching off PAR”
Claim · model-written summary
About half of wild-type cells with activated anion channels also increased cytosolic free Ca2+.
Not reportedTaxon
Verbatim
e0“In approximately half of these cells, activation of anion channels was accompanied by an increase in the cytosolic free Ca(2+) concentration”
Claim · model-written summary
Anion-channel activity was higher in cells with a parallel cytosolic Ca2+ increase than in cells with steady Ca2+.
Not reportedTaxon
Verbatim
e0“The activity of anion channels was higher in cells showing a parallel increase in cytosolic Ca(2+) than in those with steady Ca(2+) levels”
Claim · model-written summary
NtMPK4 silencing repressed darkness-induced anion-channel activation and Ca2+ signals.
- Taxon
- Nicotiana tabacumNicotiana tabacumt0
- Treatment
- NtMPK4-silencede0
- Outcome
- darkness-induced anion channel activation and Ca(2+) signalse0
- Direction
- repressede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both the darkness-induced anion channel activation and Ca(2+) signals were repressed in NtMPK4-silenced guard cells”
t0“Nicotiana tabacum”
The same questions in other papers
loss of function · physiology: gas exchange · Nicotiana tabacum (tobacco)Positive and negative results
2 in the opposite direction
- no effect
- no effect
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.