Abstract
The cellular polyamines putrescine, spermidine, and spermine are ubiquitous in nature and have been implicated in a wide range of growth and developmental processes. There is little information, however, on mutant plants or animals defective in the synthesis of polyamines. The Arabidopsis genome has two genes encoding spermidine synthase, SPDS1 and SPDS2. In this paper, we describe T-DNA insertion mutants of both of these genes. While each mutant allele shows normal growth, spds1-1 spds2-1 double-mutant seeds are abnormally shrunken and they have embryos that are arrested morphologically at the heart-torpedo transition stage. These seeds contain significantly reduced levels of spermidine and high levels of its precursor, putrescine. The embryo lethal phenotype of spds1-1 spds2-1 is complemented by the wild-type SPDS1 gene. In addition, we observed a nearly identical seed phenotype among an F2 seed population from the cross between the spds2-1 allele and SPDS1 RNA interference transgenic lines. These data provide the first genetic evidence indicating a critical role of the spermidine synthase in plant embryo development.
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Claims 7
Claim · model-written summary
Arabidopsis spds1-1 spds2-1 double-mutant seeds are abnormally shrunken and their embryos are arrested morphologically at the heart-torpedo transition stage.
- Taxon
- Arabidopsis
Arabidopsist0 - Material
- spds1-1 spds2-1 double-mutante0
- Outcome
- seeds are abnormally shrunken and they have embryos that are arrested morphologically at the heart-torpedo transition stagee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“spds1-1 spds2-1 double-mutant seeds are abnormally shrunken and they have embryos that are arrested morphologically at the heart-torpedo transition stage”
t0“Arabidopsis”
Claim · model-written summary
Each single spds1 or spds2 T-DNA mutant allele shows normal growth in Arabidopsis.
- Taxon
- ArabidopsisArabidopsist0
- Material
- each mutant allelee0
- Outcome
- normal growthe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“While each mutant allele shows normal growth”
t0“Arabidopsis”
Claim · model-written summary
Seeds of the Arabidopsis double mutant contain significantly reduced levels of spermidine.
- Taxon
- ArabidopsisArabidopsist0
- Outcome
- levels of spermidinee0
- Direction
- reducede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significantly reduced levels of spermidine”
t0“Arabidopsis”
Claim · model-written summary
Seeds of the Arabidopsis double mutant contain high levels of the spermidine precursor putrescine.
- Taxon
- ArabidopsisArabidopsist0
- Outcome
- levels of its precursor, putrescinee0
- Direction
- higherinferrede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“high levels of its precursor, putrescine”
t0“Arabidopsis”
Claim · model-written summary
The embryo lethal phenotype of the Arabidopsis spds1-1 spds2-1 double mutant is complemented by the wild-type SPDS1 gene.
- Taxon
- ArabidopsisArabidopsist0
- Material
- spds1-1 spds2-1e0
- Treatment
- wild-type SPDS1 genee0
- Outcome
- embryo lethal phenotypee0
- Direction
- complementede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The embryo lethal phenotype of spds1-1 spds2-1 is complemented by the wild-type SPDS1 gene”
t0“Arabidopsis”
Claim · model-written summary
An F2 seed population from the cross of the spds2-1 allele with SPDS1 RNA interference transgenic lines showed a nearly identical seed phenotype to the double mutant.
- Taxon
- ArabidopsisArabidopsist0
- Material
- F2 seed populatione0
- Outcome
- nearly identical seed phenotypee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“we observed a nearly identical seed phenotype among an F2 seed population from the cross between the spds2-1 allele and SPDS1 RNA interference transgenic lines”
t0“Arabidopsis”
Claim · model-written summary
The authors conclude that spermidine synthase plays a critical role in plant embryo development, based on genetic evidence.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- spermidine synthasee0
- Outcome
- embryo developmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These data provide the first genetic evidence indicating a critical role of the spermidine synthase in plant embryo development”
t0“Arabidopsis”