Abstract
Abscisic acid (ABA) is an important phytohormone regulating various cellular processes in plants, including stomatal opening and seed germination. Although protein phosphorylation via mitogen-activated protein kinases (MAPKs) has been suggested to be important in ABA signaling, the corresponding phosphatases are largely unknown. Here, we show that a member of the Protein Phosphatase 2C (PP2C) family in Arabidopsis (Arabidopsis thaliana), PP2C5, is acting as a MAPK phosphatase. The PP2C5 protein colocalizes and directly interacts with stress-induced MPK3, MPK4, and MPK6, predominantly in the nucleus. Importantly, altered PP2C5 levels affect MAPK activation. Whereas Arabidopsis plants depleted of PP2C5 show an enhanced ABA-induced activation of MPK3 and MPK6, ectopic expression of PP2C5 in tobacco (Nicotiana benthamiana) resulted in the opposite effect, with the two MAPKs salicylic acid-induced protein kinase and wound-induced protein kinase not being activated any longer after ABA treatment. Moreover, depletion of PP2C5, whose gene expression itself is affected by ABA treatment, resulted in altered ABA responses. Loss-of-function mutation in PP2C5 or AP2C1, a close PP2C5 homolog, resulted in an increased stomatal aperture under normal growth conditions and a partial ABA-insensitive phenotype in seed germination that was most prominent in the pp2c5 ap2c1 double mutant line. In addition, the response of ABA-inducible genes such as ABI1, ABI2, RD29A, and Erd10 was reduced in the mutant plants. Thus, we suggest that PP2C5 acts as a MAPK phosphatase that positively regulates seed germination, stomatal closure, and ABA-inducible gene expression.
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Claims 8
Claim · model-written summary
PP2C5 colocalizes and directly interacts with MPK3, MPK4 and MPK6 in the nucleus.
- Taxon
- Arabidopsis
Arabidopsist0 - Gene
- PP2C5e0
- Outcome
- colocalizes and directly interacts with stress-induced MPK3, MPK4, and MPK6e0
- Setting
- nucleuse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The PP2C5 protein colocalizes and directly interacts with stress-induced MPK3, MPK4, and MPK6, predominantly in the nucleus.”
t0“Arabidopsis”
Claim · model-written summary
PP2C5 depletion enhances ABA-induced MPK3 and MPK6 activation in Arabidopsis.
- Taxon
- ArabidopsisArabidopsise0
- Treatment
- depleted of PP2C5e0
- Gene
- PP2C5e0
- Outcome
- ABA-induced activation of MPK3 and MPK6e0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Arabidopsis plants depleted of PP2C5 show an enhanced ABA-induced activation of MPK3 and MPK6”
Claim · model-written summary
Ectopic PP2C5 expression prevented ABA activation of two tobacco MAPKs.
- Taxon
- tobacco
Nicotiana tabacume0 - Treatment
- ectopic expression of PP2C5e0
- Gene
- PP2C5e0
- Outcome
- salicylic acid-induced protein kinase and wound-induced protein kinasee0
- Direction
- not being activated any longere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ectopic expression of PP2C5 in tobacco (Nicotiana benthamiana) resulted in the opposite effect, with the two MAPKs salicylic acid-induced protein kinase and wound-induced protein kinase not being activated any longer after ABA treatment.”
Claim · model-written summary
ABA treatment affects PP2C5 gene expression.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- ABA treatmente0
- Gene
- PP2C5e0
- Outcome
- gene expressione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PP2C5, whose gene expression itself is affected by ABA treatment”
t0“Arabidopsis”
Claim · model-written summary
PP2C5 or AP2C1 loss of function increases stomatal aperture under normal growth conditions.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- Loss-of-function mutation in PP2C5 or AP2C1e0
- Gene
- PP2C5 or AP2C1e0
- Outcome
- stomatal aperturee0
- Direction
- increasede0
- Qualifier
- normal growth conditionse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Loss-of-function mutation in PP2C5 or AP2C1, a close PP2C5 homolog, resulted in an increased stomatal aperture under normal growth conditions”
t0“Arabidopsis”
Claim · model-written summary
PP2C5 or AP2C1 mutation caused partial ABA-insensitive seed germination, strongest in the double mutant.
- Taxon
- ArabidopsisArabidopsist0
- Material
- pp2c5 ap2c1 double mutant linee0
- Treatment
- Loss-of-function mutation in PP2C5 or AP2C1e0
- Gene
- PP2C5 or AP2C1e0
- Outcome
- partial ABA-insensitive phenotype in seed germinatione0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Loss-of-function mutation in PP2C5 or AP2C1, a close PP2C5 homolog, resulted in an increased stomatal aperture under normal growth conditions and a partial ABA-insensitive phenotype in seed germination that was most prominent in the pp2c5 ap2c1 double mutant line.”
t0“Arabidopsis”
Claim · model-written summary
Mutants had reduced ABA-inducible gene responses.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- mutant plantse0
- Gene
- ABI1, ABI2, RD29A, and Erd10e0
- Outcome
- response of ABA-inducible genese0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the response of ABA-inducible genes such as ABI1, ABI2, RD29A, and Erd10 was reduced in the mutant plants.”
t0“Arabidopsis”
Claim · model-written summary
The authors suggest that PP2C5 positively regulates seed germination, stomatal closure and ABA-inducible expression.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- PP2C5e0
- Outcome
- seed germination, stomatal closure, and ABA-inducible gene expressione0
- Direction
- positively regulatese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PP2C5 acts as a MAPK phosphatase that positively regulates seed germination, stomatal closure, and ABA-inducible gene expression.”
t0“Arabidopsis”
The same questions in other papers
overexpression · physiology: hormones · Nicotiana tabacum (tobacco)Positive and negative results
3 in the opposite direction
- positive
- positive
- positive
loss of function · physiology: gas exchange · ArabidopsisPositive and negative results
19 papers in the same direction as this paper · 5 in the opposite direction
- positive
- positive
- positive
21 papers more in this group
See all 25 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.