Abstract
Phosphatidic acid (PA) and phytosphingosine 1-phosphate (phyto-S1P) both are lipid messengers involved in plant response to abscisic acid (ABA). Our previous data indicate that PA binds to sphingosine kinase (SPHK) and increases its phyto-S1P-producing activity. To understand the cellular and physiological functions of the PA-SPHK interaction, we isolated Arabidopsis thaliana SPHK mutants sphk1-1 and sphk2-1 and characterized them, together with phospholipase Dα1 knock-out, pldα1, in plant response to ABA. Compared with wild-type (WT) plants, the SPHK mutants and pldα1 all displayed decreased sensitivity to ABA-promoted stomatal closure. Phyto-S1P promoted stomatal closure in sphk1-1 and sphk2-1, but not in pldα1, whereas PA promoted stomatal closure in sphk1-1, sphk2-1, and pldα1. The ABA activation of PLDα1 in leaves and protoplasts was attenuated in the SPHK mutants, and the ABA activation of SPHK was reduced in pldα1. In response to ABA, the accumulation of long-chain base phosphates was decreased in pldα1, whereas PA production was decreased in SPHK mutants, compared with WT. Collectively, these results indicate that SPHK and PLDα1 act together in ABA response and that SPHK and phyto-S1P act upstream of PLDα1 and PA in mediating the ABA response. PA is involved in the activation of SPHK, and activation of PLDα1 requires SPHK activity. The data suggest that SPHK/phyto-S1P and PLDα1A are co-dependent in amplification of response to ABA, mediating stomatal closure in Arabidopsis.
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Claims 15
Claim · model-written summary
SPHK mutants showed decreased sensitivity to ABA-promoted stomatal closure.
- Taxon
- Arabidopsis thaliana
Arabidopsis thalianae1 - Material
- SPHK mutantse0
- Treatment
- ABA-promotede0
- Outcome
- sensitivity to ABA-promoted stomatal closuree0
- Direction
- decreasede0
- Comparator
- wild-type (WT) plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared with wild-type (WT) plants, the SPHK mutants and pldα1 all displayed decreased sensitivity to ABA-promoted stomatal closure”
e1“Arabidopsis thaliana”
Claim · model-written summary
pldα1 showed decreased sensitivity to ABA-promoted stomatal closure.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Material
- pldα1e0
- Treatment
- ABA-promotede0
- Outcome
- sensitivity to ABA-promoted stomatal closuree0
- Direction
- decreasede0
- Comparator
- wild-type (WT) plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Compared with wild-type (WT) plants, the SPHK mutants and pldα1 all displayed decreased sensitivity to ABA-promoted stomatal closure”
e1“Arabidopsis thaliana”
Claim · model-written summary
Phyto-S1P promoted stomatal closure in sphk1-1.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Material
- sphk1-1e0
- Treatment
- Phyto-S1Pe0
- Outcome
- stomatal closuree0
- Direction
- promotede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phyto-S1P promoted stomatal closure in sphk1-1 and sphk2-1, but not in pldα1”
e1“Arabidopsis thaliana”
Claim · model-written summary
Phyto-S1P promoted stomatal closure in sphk2-1.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Material
- sphk2-1e0
- Treatment
- Phyto-S1Pe0
- Outcome
- stomatal closuree0
- Direction
- promotede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phyto-S1P promoted stomatal closure in sphk1-1 and sphk2-1, but not in pldα1”
e1“Arabidopsis thaliana”
Claim · model-written summary
Phyto-S1P did not promote stomatal closure in pldα1.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Material
- pldα1e0
- Treatment
- Phyto-S1Pe0
- Outcome
- stomatal closuree0
- Direction
- note0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phyto-S1P promoted stomatal closure in sphk1-1 and sphk2-1, but not in pldα1”
e1“Arabidopsis thaliana”
Claim · model-written summary
PA promoted stomatal closure in sphk1-1.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Material
- sphk1-1e0
- Treatment
- PAe0
- Outcome
- stomatal closuree0
- Direction
- promotede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PA promoted stomatal closure in sphk1-1, sphk2-1, and pldα1”
e1“Arabidopsis thaliana”
Claim · model-written summary
PA promoted stomatal closure in sphk2-1.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Material
- sphk2-1e0
- Treatment
- PAe0
- Outcome
- stomatal closuree0
- Direction
- promotede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PA promoted stomatal closure in sphk1-1, sphk2-1, and pldα1”
e1“Arabidopsis thaliana”
Claim · model-written summary
PA promoted stomatal closure in pldα1.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Material
- pldα1e0
- Treatment
- PAe0
- Outcome
- stomatal closuree0
- Direction
- promotede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PA promoted stomatal closure in sphk1-1, sphk2-1, and pldα1”
e1“Arabidopsis thaliana”
Claim · model-written summary
ABA activation of PLDα1 was attenuated in SPHK mutants.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Material
- SPHK mutantse0
- Treatment
- ABAe0
- Outcome
- activation of PLDα1e0
- Direction
- attenuatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The ABA activation of PLDα1 in leaves and protoplasts was attenuated in the SPHK mutants”
e1“Arabidopsis thaliana”
Claim · model-written summary
ABA activation of SPHK was reduced in pldα1.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Material
- pldα1e0
- Treatment
- ABAe0
- Outcome
- activation of SPHKe0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the ABA activation of SPHK was reduced in pldα1”
e1“Arabidopsis thaliana”
Claim · model-written summary
ABA-induced long-chain base phosphate accumulation decreased in pldα1.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Material
- pldα1e0
- Treatment
- ABAe0
- Outcome
- accumulation of long-chain base phosphatese0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In response to ABA, the accumulation of long-chain base phosphates was decreased in pldα1”
e1“Arabidopsis thaliana”
Claim · model-written summary
ABA-induced PA production decreased in SPHK mutants versus wild type.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae2
- Material
- SPHK mutantse0
- Treatment
- ABAe1
- Outcome
- PA productione0
- Direction
- decreasede0
- Comparator
- WTe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PA production was decreased in SPHK mutants, compared with WT”
e1“In response to ABA”
e2“Arabidopsis thaliana”
Claim · model-written summary
The authors infer SPHK and phyto-S1P act upstream of PLDα1 and PA during ABA response.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Gene
- SPHKe0
- Outcome
- ABA responsee0
- Qualifier
- act upstream of PLDα1 and PAe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SPHK and phyto-S1P act upstream of PLDα1 and PA in mediating the ABA response”
e1“Arabidopsis thaliana”
Claim · model-written summary
The authors infer PA activates SPHK.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Gene
- SPHKe0
- Compound
- PAe0
- Outcome
- activation of SPHKe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PA is involved in the activation of SPHK”
e1“Arabidopsis thaliana”
Claim · model-written summary
The authors infer PLDα1 activation requires SPHK activity.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Gene
- SPHKe0
- Outcome
- activation of PLDα1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“activation of PLDα1 requires SPHK activity”
e1“Arabidopsis thaliana”
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