Abstract
Suc, an end product of photosynthesis, is metabolized by Suc synthase in sink organs as an initial step in the biosynthesis of storage products. Suc synthase activity is known to be regulated by reversible phosphorylation, but the details of this process are unclear at present. Rice SPK, a calcium-dependent protein kinase, is expressed uniquely in the endosperm of immature seed, and its involvement in the biosynthetic pathways of storage products was suggested. Antisense SPK transformants lacked the ability to accumulate storage products such as starch, but produced watery seed with a large amount of Suc instead, as the result of an inhibition of Suc degradation. Analysis of in vitro phosphorylation indicated that SPK phosphorylated specifically a Ser residue in Suc synthase that has been shown to be important for its activity in the degradation of Suc. This finding suggests that SPK is involved in the activation of Suc synthase. It appears that SPK is a Suc synthase kinase that may be important for supplying substrates for the biosynthesis of storage products.
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Claims 6
Claim · model-written summary
Antisense SPK transformants of rice lacked the ability to accumulate storage products such as starch.
- Taxon
- Rice
Oryza sativat0 - Treatment
- Antisense SPK transformantse1
- Gene
- SPKe1
- Outcome
- accumulate storage products such as starche1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice SPK, a Calmodulin-Like Domain Protein Kinase”
e1“Antisense SPK transformants lacked the ability to accumulate storage products such as starch”
Claim · model-written summary
Antisense SPK transformants of rice produced watery seed with a large amount of Suc.
- Taxon
- RiceOryza sativat0
- Treatment
- Antisense SPK transformantse1
- Gene
- SPKe1
- Outcome
- watery seed with a large amount of Suce2
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice SPK, a Calmodulin-Like Domain Protein Kinase”
e1“Antisense SPK transformants lacked the ability to accumulate storage products such as starch”
e2“produced watery seed with a large amount of Suc instead, as the result of an inhibition of Suc degradation”
Claim · model-written summary
The accumulation of Suc in antisense SPK seed results from an inhibition of Suc degradation.
- Taxon
- RiceOryza sativat0
- Outcome
- a large amount of Suce2
- Qualifier
- inhibition of Suc degradatione2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice SPK, a Calmodulin-Like Domain Protein Kinase”
e2“produced watery seed with a large amount of Suc instead, as the result of an inhibition of Suc degradation”
Claim · model-written summary
In vitro, SPK phosphorylated a specific Ser residue in Suc synthase.
- Taxon
- RiceOryza sativat0
- Gene
- Suc synthasee3
- Outcome
- phosphorylated specifically a Ser residuee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice SPK, a Calmodulin-Like Domain Protein Kinase”
e3“Analysis of in vitro phosphorylation indicated that SPK phosphorylated specifically a Ser residue in Suc synthase”
Claim · model-written summary
SPK appears to be involved in the activation of Suc synthase.
- Taxon
- RiceOryza sativat0
- Gene
- SPKe4
- Outcome
- activation of Suc synthasee4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice SPK, a Calmodulin-Like Domain Protein Kinase”
e4“This finding suggests that SPK is involved in the activation of Suc synthase”
Claim · model-written summary
Rice SPK is expressed uniquely in the endosperm of immature seed.
- Taxon
- RiceOryza sativae0
- Organ / stage
- endosperm of immature seede0
- Gene
- SPKe0
- Outcome
- expressed uniquelye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rice SPK, a calcium-dependent protein kinase, is expressed uniquely in the endosperm of immature seed”
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