Abstract
BACKGROUND: The actin cytoskeleton is involved in the responses of plants to environmental signals. Actin bundles play the role of tracks in chloroplast movements activated by light. Chloroplasts redistribute in response to blue light in the mesophyll cells of Nicotiana tabacum. The aim of this work was to study the relationship between chloroplast responses and the organization of actin cytoskeleton in living tobacco cells. Chloroplast movements were measured photometrically as changes in light transmission through the leaves. The actin cytoskeleton, labeled with plastin-GFP, was visualised by confocal microscopy. RESULTS: The actin cytoskeleton was affected by strong blue and red light. No blue light specific actin reorganization was detected. EGTA and trifluoperazine strongly inhibited chloroplast responses and disrupted the integrity of the cytoskeleton. This disruption was reversible by Ca(2+) or Mg(2+). Additionally, the effect of trifluoperazine was reversible by light. Wortmannin, an inhibitor of phosphoinositide kinases, potently inhibited chloroplast responses but did not influence the actin cytoskeleton at the same concentration. Also this inhibition was reversed by Ca(2+) and Mg(2+). Magnesium ions were equally or more effective than Ca(2+) in restoring chloroplast motility after treatment with EGTA, trifluoperazine or wortmannin. CONCLUSION: The architecture of the actin cytoskeleton in the mesophyll of tobacco is significantly modulated by strong light. This modulation does not affect the direction of chloroplast redistribution in the cell. Calcium ions have multiple functions in the mechanism of the movements. Our results suggest also that Mg(2+) is a regulatory molecule cooperating with Ca(2+) in the signaling pathway of blue light-induced tobacco chloroplast movements.
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Claims 11
Claim · model-written summary
Strong blue and red light affected the actin cytoskeleton.
- Taxon
- Nicotiana tabacumL.
Nicotiana tabacumt0 - Treatment
- strong blue and red lighte0
- Outcome
- actin cytoskeletone0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The actin cytoskeleton was affected by strong blue and red light.”
t0“Nicotiana tabacumL.”
Claim · model-written summary
Blue-light-specific actin reorganization was not detected.
- Taxon
- Nicotiana tabacumL.Nicotiana tabacumt0
- Outcome
- No blue light specific actin reorganizatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No blue light specific actin reorganization was detected.”
t0“Nicotiana tabacumL.”
Claim · model-written summary
EGTA and trifluoperazine strongly inhibited chloroplast responses.
- Taxon
- Nicotiana tabacumL.Nicotiana tabacumt0
- Treatment
- EGTA and trifluoperazinee0
- Outcome
- chloroplast responsese0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“EGTA and trifluoperazine strongly inhibited chloroplast responses”
t0“Nicotiana tabacumL.”
Claim · model-written summary
EGTA and trifluoperazine disrupted cytoskeletal integrity.
- Taxon
- Nicotiana tabacumL.Nicotiana tabacumt0
- Treatment
- EGTA and trifluoperazinee0
- Outcome
- integrity of the cytoskeletone0
- Direction
- disruptede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“EGTA and trifluoperazine strongly inhibited chloroplast responses and disrupted the integrity of the cytoskeleton.”
t0“Nicotiana tabacumL.”
Claim · model-written summary
Ca(2+) or Mg(2+) reversed cytoskeletal disruption.
- Taxon
- Nicotiana tabacumL.Nicotiana tabacumt0
- Treatment
- Ca(2+) or Mg(2+)e0
- Outcome
- disruptione0
- Direction
- reversiblee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This disruption was reversible by Ca(2+) or Mg(2+).”
t0“Nicotiana tabacumL.”
Claim · model-written summary
Light reversed the effect of trifluoperazine.
- Taxon
- Nicotiana tabacumL.Nicotiana tabacumt0
- Treatment
- lighte0
- Outcome
- effect of trifluoperazinee0
- Direction
- reversiblee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the effect of trifluoperazine was reversible by light.”
t0“Nicotiana tabacumL.”
Claim · model-written summary
Wortmannin inhibited chloroplast responses.
- Taxon
- Nicotiana tabacumL.Nicotiana tabacumt0
- Treatment
- Wortmannine0
- Outcome
- chloroplast responsese0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Wortmannin, an inhibitor of phosphoinositide kinases, potently inhibited chloroplast responses”
t0“Nicotiana tabacumL.”
Claim · model-written summary
Wortmannin did not influence the actin cytoskeleton at that concentration.
- Taxon
- Nicotiana tabacumL.Nicotiana tabacumt0
- Treatment
- Wortmannine0
- Outcome
- actin cytoskeletone0
- Direction
- did not influencee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Wortmannin, an inhibitor of phosphoinositide kinases, potently inhibited chloroplast responses but did not influence the actin cytoskeleton at the same concentration.”
t0“Nicotiana tabacumL.”
Claim · model-written summary
Ca(2+) and Mg(2+) reversed wortmannin inhibition.
- Taxon
- Nicotiana tabacumL.Nicotiana tabacumt0
- Treatment
- Ca(2+) and Mg(2+)e0
- Outcome
- inhibitione0
- Direction
- reversede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Also this inhibition was reversed by Ca(2+) and Mg(2+).”
t0“Nicotiana tabacumL.”
Claim · model-written summary
Mg(2+) was at least as effective as Ca(2+) in restoring chloroplast motility.
- Taxon
- Nicotiana tabacumL.Nicotiana tabacumt0
- Treatment
- Magnesium ionse0
- Outcome
- chloroplast motilitye0
- Direction
- equally or more effectivee0
- Comparator
- Ca(2+)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Magnesium ions were equally or more effective than Ca(2+) in restoring chloroplast motility after treatment with EGTA, trifluoperazine or wortmannin.”
t0“Nicotiana tabacumL.”
Claim · model-written summary
Strong-light actin modulation did not affect the direction of chloroplast redistribution.
- Taxon
- Nicotiana tabacumL.Nicotiana tabacumt0
- Organ / stage
- celle0
- Outcome
- direction of chloroplast redistributione0
- Direction
- does not affecte0
- Qualifier
- modulatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This modulation does not affect the direction of chloroplast redistribution in the cell.”
t0“Nicotiana tabacumL.”
The same questions in other papers
calcium(2+) · disease · Nicotiana tabacum (tobacco)Results agree
2 papers in the same direction as this paper
- positive
- positive
light · molecular: metabolites · Nicotiana tabacum (tobacco)Positive and negative results
7 papers in the same direction as this paper · 13 in the opposite direction
- negative
- negative
- no effect
17 papers more in this group
See all 21 papers →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.