Abstract
Of the five polyamine oxidases in Arabidopsis thaliana, AtPAO5 has a substrate preference for the tetraamine thermospermine (T-Spm) which is converted to triamine spermidine (Spd) in a back-conversion reaction in vitro. A homologue of AtPAO5 from the lycophyte Selaginella lepidophylla (SelPAO5) back-converts T-Spm to the uncommon polyamine norspermidine (NorSpd) instead of Spd. An Atpao5 loss-of-function mutant shows a strong reduced growth phenotype when growing on a T-Spm containing medium. When SelPAO5 was expressed in the Atpao5 mutant, T-Spm level decreased to almost normal values of wild type plants, and NorSpd was produced. Furthermore the reduced growth phenotype was cured by the expression of SelPAO5. Thus, a NorSpd synthesis pathway by PAO reaction and T-Spm as substrate was demonstrated in planta and the assumption that a balanced T-Spm homeostasis is needed for normal growth was strengthened.
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Claims 6
Claim · model-written summary
SelPAO5 back-converts thermospermine to norspermidine instead of spermidine.
- Taxon
- Selaginella lepidophylla
Selaginella lepidophyllae1 - Gene
- SelPAO5e1
- Outcome
- back-converts T-Spm to the uncommon polyamine norspermidinee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“A homologue of AtPAO5 from the lycophyte Selaginella lepidophylla (SelPAO5) back-converts T-Spm to the uncommon polyamine norspermidine (NorSpd) instead of Spd”
Claim · model-written summary
The Atpao5 loss-of-function mutant showed a strong reduced growth phenotype on a T-Spm containing medium.
- Taxon
- Arabidopsis thaliana
Arabidopsis thalianae0 - Material
- Atpao5 loss-of-function mutante2
- Treatment
- T-Spm containing mediume2
- Outcome
- growth phenotypee2
- Direction
- reducede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Of the five polyamine oxidases in Arabidopsis thaliana, AtPAO5 has a substrate preference for the tetraamine thermospermine (T-Spm)”
e2“An Atpao5 loss-of-function mutant shows a strong reduced growth phenotype when growing on a T-Spm containing medium”
Claim · model-written summary
Expression of SelPAO5 in the Atpao5 mutant decreased T-Spm level to almost normal values of wild type plants.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae0
- Treatment
- SelPAO5 was expressed in the Atpao5 mutante3
- Gene
- SelPAO5e3
- Outcome
- T-Spm levele3
- Direction
- decreasede3
- Comparator
- wild type plantse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Of the five polyamine oxidases in Arabidopsis thaliana, AtPAO5 has a substrate preference for the tetraamine thermospermine (T-Spm)”
e3“When SelPAO5 was expressed in the Atpao5 mutant, T-Spm level decreased to almost normal values of wild type plants, and NorSpd was produced”
Claim · model-written summary
NorSpd was produced in the Atpao5 mutant expressing SelPAO5.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae0
- Gene
- SelPAO5e3
- Outcome
- NorSpd was producede3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Of the five polyamine oxidases in Arabidopsis thaliana, AtPAO5 has a substrate preference for the tetraamine thermospermine (T-Spm)”
e3“When SelPAO5 was expressed in the Atpao5 mutant, T-Spm level decreased to almost normal values of wild type plants, and NorSpd was produced”
Claim · model-written summary
Expression of SelPAO5 cured the reduced growth phenotype of the Atpao5 mutant.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae0
- Treatment
- expression of SelPAO5e4
- Gene
- SelPAO5e4
- Outcome
- reduced growth phenotypee4
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Of the five polyamine oxidases in Arabidopsis thaliana, AtPAO5 has a substrate preference for the tetraamine thermospermine (T-Spm)”
e4“Furthermore the reduced growth phenotype was cured by the expression of SelPAO5”
Claim · model-written summary
Balanced T-Spm homeostasis is needed for normal growth, as the study strengthens this assumption.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae0
- Outcome
- normal growthe5
- Qualifier
- balanced T-Spm homeostasise5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Of the five polyamine oxidases in Arabidopsis thaliana, AtPAO5 has a substrate preference for the tetraamine thermospermine (T-Spm)”
e5“a balanced T-Spm homeostasis is needed for normal growth”