Abstract
S-Adenosylmethionine (SAM) is formed exclusively in the cytosol but plays a major role in plastids; SAM can either act as a methyl donor for the biogenesis of small molecules such as prenyllipids and macromolecules or as a regulator of the synthesis of aspartate-derived amino acids. Because the biosynthesis of SAM is restricted to the cytosol, plastids require a SAM importer. However, this transporter has not yet been identified. Here, we report the molecular and functional characterization of an Arabidopsis thaliana gene designated SAM TRANSPORTER1 (SAMT1), which encodes a plastid metabolite transporter required for the import of SAM from the cytosol. Recombinant SAMT1 produced in yeast cells, when reconstituted into liposomes, mediated the counter-exchange of SAM with SAM and with S-adenosylhomocysteine, the by-product and inhibitor of transmethylation reactions using SAM. Insertional mutation in SAMT1 and virus-induced gene silencing of SAMT1 in Nicotiana benthamiana caused severe growth retardation in mutant plants. Impaired function of SAMT1 led to decreased accumulation of prenyllipids and mainly affected the chlorophyll pathway. Biochemical analysis suggests that the latter effect represents one prominent example of the multiple events triggered by undermethylation, when there is decreased SAM flux into plastids.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 6
Claim · model-written summary
SAMT1 is a plastid transporter required for import of SAM from the cytosol in Arabidopsis thaliana.
- Taxon
- Arabidopsis thaliana
Arabidopsis thalianae1 - Gene
- SAMT1e1
- Outcome
- import of SAM from the cytosole1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Here, we report the molecular and functional characterization of an Arabidopsis thaliana gene designated SAM TRANSPORTER1 (SAMT1), which encodes a plastid metabolite transporter required for the import of SAM from the cytosol”
Claim · model-written summary
Recombinant SAMT1 mediated counter-exchange of SAM with SAM and with S-adenosylhomocysteine in liposomes.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Gene
- SAMT1e2
- Outcome
- counter-exchange of SAMe2
- Qualifier
- with SAM and with S-adenosylhomocysteinee2
- Setting
- liposomese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Here, we report the molecular and functional characterization of an Arabidopsis thaliana gene designated SAM TRANSPORTER1 (SAMT1), which encodes a plastid metabolite transporter required for the import of SAM from the cytosol”
e2“Recombinant SAMT1 produced in yeast cells, when reconstituted into liposomes, mediated the counter-exchange of SAM with SAM and with S-adenosylhomocysteine”
Claim · model-written summary
Insertional mutation in SAMT1 decreased growth of Arabidopsis thaliana mutant plants.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Treatment
- Insertional mutation in SAMT1e3
- Gene
- SAMT1e3
- Outcome
- growthe3
- Direction
- decreaseinferrede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Here, we report the molecular and functional characterization of an Arabidopsis thaliana gene designated SAM TRANSPORTER1 (SAMT1), which encodes a plastid metabolite transporter required for the import of SAM from the cytosol”
e3“Insertional mutation in SAMT1 and virus-induced gene silencing of SAMT1 in Nicotiana benthamiana caused severe growth retardation in mutant plants”
Claim · model-written summary
Virus-induced gene silencing of SAMT1 caused severe growth retardation in Nicotiana benthamiana.
- Taxon
- Nicotiana benthamiana
Nicotiana benthamianae3 - Treatment
- virus-induced gene silencing of SAMT1e3
- Gene
- SAMT1e3
- Outcome
- growthe3
- Direction
- decreaseinferrede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“Insertional mutation in SAMT1 and virus-induced gene silencing of SAMT1 in Nicotiana benthamiana caused severe growth retardation in mutant plants”
Claim · model-written summary
Impaired SAMT1 function decreased accumulation of prenyllipids in Arabidopsis thaliana.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Treatment
- Impaired function of SAMT1e4
- Gene
- SAMT1e4
- Outcome
- accumulation of prenyllipidse4
- Direction
- decreasede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Here, we report the molecular and functional characterization of an Arabidopsis thaliana gene designated SAM TRANSPORTER1 (SAMT1), which encodes a plastid metabolite transporter required for the import of SAM from the cytosol”
e4“Impaired function of SAMT1 led to decreased accumulation of prenyllipids and mainly affected the chlorophyll pathway”
Claim · model-written summary
The chlorophyll pathway effect is one prominent example of undermethylation caused by decreased SAM flux into plastids.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Gene
- SAMT1e4
- Outcome
- chlorophyll pathwaye4
- Qualifier
- undermethylation, when there is decreased SAM flux into plastidse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Here, we report the molecular and functional characterization of an Arabidopsis thaliana gene designated SAM TRANSPORTER1 (SAMT1), which encodes a plastid metabolite transporter required for the import of SAM from the cytosol”
e4“Impaired function of SAMT1 led to decreased accumulation of prenyllipids and mainly affected the chlorophyll pathway”
e5“Biochemical analysis suggests that the latter effect represents one prominent example of the multiple events triggered by undermethylation, when there is decreased SAM flux into plastids”
The same questions in other papers
loss of function · growth · Nicotiana benthamianaPositive and negative results
16 papers in the same direction as this paper · 4 in the opposite direction
- positive
- positive
- positive
17 papers more in this group
See all 21 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.