Abstract
N-acetylserotonin methyltransferase (ASMT) is the final enzyme in a biosynthetic pathway that produces melatonin. ASMT may play a rate-limiting role in the production of this bioactive molecule in plants. There are three ASMT genes (ASMT1-ASMT3) in the rice genome, but only ASMT1 has been functionally characterized. A major barrier to further progress in characterizing these genes has been a failure of functional expression within the Escherichia coli. Purified recombinant ASMT2 and ASMT3 are inactive in ASMT enzyme catalysis. To determine the biological functions of ASMT2 and ASMT3, we first overexpressed them in rice calli, which resulted in enhanced production of melatonin in the respective transgenic calli. To further corroborate the functions of ASMT2 and ASMT3 as ASMT genes, we generated stable transgenic rice plants. ASMT enzyme activity was increased in comparison with the wild type in T2 homozygous transgenic rice plants expressing three ASMT genes independently. When seedlings were treated with 1 mm N-acetylserotonin (NAS), leaf melatonin contents were higher in the three transgenic lines than in the wild type. There were no significant differences between the transgenic lines and the wild type without this treatment. ASMT1 and ASMT2 transcripts were highly expressed in stems and flowers, but ASMT3 was barely detectable in any of the plant organs. All three ASMT mRNAs were simultaneously induced in treatments with abscisic and methyl jasmonic acids.
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Claims 8
Claim · model-written summary
Recombinant ASMT2 and ASMT3 were inactive in the enzyme assay.
- Taxon
- rice plants
Oryza sativat0 - Gene
- ASMT2 and ASMT3e0
- Outcome
- inactive in ASMT enzyme catalysise0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Purified recombinant ASMT2 and ASMT3 are inactive in ASMT enzyme catalysis.”
t0“rice plants”
Claim · model-written summary
ASMT activity increased in transgenic rice plants expressing the three genes independently relative to wild type.
- Taxon
- riceOryza sativae0
- Material
- T2 homozygous transgenic rice plantse0
- Treatment
- expressing three ASMT genes independentlye0
- Gene
- ASMTe0
- Outcome
- ASMT enzyme activitye0
- Direction
- increasede0
- Comparator
- wild typee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ASMT enzyme activity was increased in comparison with the wild type in T2 homozygous transgenic rice plants expressing three ASMT genes independently.”
Claim · model-written summary
After NAS treatment, transgenic rice seedlings had higher leaf melatonin than wild type.
- Taxon
- rice plantsOryza sativat0
- Material
- three transgenic linese0
- Organ / stage
- leafe0
- Treatment
- treated with 1 mm N-acetylserotonin (NAS)e0
- Outcome
- leaf melatonin contentse0
- Direction
- highere0
- Comparator
- wild typee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When seedlings were treated with 1 mm N-acetylserotonin (NAS), leaf melatonin contents were higher in the three transgenic lines than in the wild type.”
t0“rice plants”
Claim · model-written summary
Without NAS treatment, melatonin content did not differ significantly between transgenic and wild type rice.
- Taxon
- rice plantsOryza sativat0
- Treatment
- transgenic linese0
- Outcome
- leaf melatonin contentse1
- Direction
- no significant differencese0
- Comparator
- wild typee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There were no significant differences between the transgenic lines and the wild type without this treatment.”
e1“leaf melatonin contents”
t0“rice plants”
Claim · model-written summary
ASMT1 and ASMT2 transcripts were highly expressed in stems and flowers.
- Taxon
- rice plantsOryza sativat0
- Organ / stage
- stems and flowerse0
- Gene
- ASMT1 and ASMT2e0
- Outcome
- transcripts were highly expressede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ASMT1 and ASMT2 transcripts were highly expressed in stems and flowers”
t0“rice plants”
Claim · model-written summary
ASMT3 transcripts were barely detectable in plant organs.
- Taxon
- rice plantsOryza sativat0
- Organ / stage
- plant organse0
- Gene
- ASMT3e0
- Outcome
- barely detectablee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“ASMT3 was barely detectable in any of the plant organs”
t0“rice plants”
Claim · model-written summary
Abscisic acid induced all three ASMT transcripts.
- Taxon
- rice plantsOryza sativat0
- Treatment
- abscisice0
- Gene
- ASMT mRNAse0
- Outcome
- ASMT mRNAse0
- Direction
- inducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All three ASMT mRNAs were simultaneously induced in treatments with abscisic and methyl jasmonic acids.”
t0“rice plants”
Claim · model-written summary
Methyl jasmonic acid induced all three ASMT transcripts.
- Taxon
- rice plantsOryza sativat0
- Treatment
- methyl jasmonic acidse0
- Gene
- ASMT mRNAse0
- Outcome
- ASMT mRNAse0
- Direction
- inducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All three ASMT mRNAs were simultaneously induced in treatments with abscisic and methyl jasmonic acids.”
t0“rice plants”
The same questions in other papers
methyl · molecular: metabolites · Oryza sativa (rice)Positive and negative results
1 in the opposite direction
- negative
jasmonic acid · molecular: metabolites · Oryza sativa (rice)Positive and negative results
7 papers in the same direction as this paper · 3 in the opposite direction
- no effect
- no effect
- negative
7 papers more in this group
See all 11 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.