Abstract
The coding sequence of the wild-type, cys-sensitive, cysE gene from Escherichia coli, which encodes an enzyme of the cysteine biosynthetic pathway, namely serine acetyltransferase (SAT, EC 2.3.1. 30), was introduced into the genome of potato plants under the control of the cauliflower mosaic virus 35S promoter. In order to target the protein into the chloroplast, cysE was translationally fused to the 5'-signal sequence of rbcS from Arabidopsis thaliana. Transgenic plants showed a high accumulation of the cysE mRNA. The chloroplastic localisation of the E. coli SAT protein was demonstrated by determination of enzymatic activities in enriched organelle fractions. Crude leaf extracts of these plants exhibited up to 20-fold higher SAT activity than those prepared from wild-type plants. The transgenic potato plants expressing the E. coli gene showed not only increased levels of enzyme activity but also exhibited elevated levels of cysteine and glutathione in leaves. Both were up to twofold higher than in control plants. However, the thiol content in tubers of transgenic lines was unaffected. The alterations observed in leaf tissue had no effect on the expression of O-acetylserine(thiol)-lyase, the enzyme which converts O-acetylserine, the product of SAT, to cysteine. Only a minor effect on its enzymatic activity was observed. In conclusion, the results presented here demonstrate the importance of SAT in plant cysteine biosynthesis and show that production of cysteine and related sulfur-containing compounds can be enhanced by metabolic engineering.
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Claims 7
Claim · model-written summary
Transgenic potato plants expressing the bacterial SAT gene had up to 20-fold higher SAT activity in leaf extracts than wild-type plants.
- Taxon
- potato
Solanum tuberosumt0 - Organ / stage
- leafe1
- Treatment
- Expression of a bacterial serine acetyltransferaset0
- Gene
- SATe1
- Outcome
- SAT activitye1
- Direction
- highere1
- Value
- up to 20-folde1
- Comparator
- wild-type plantse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Expression of a bacterial serine acetyltransferase in transgenic potato plants leads to increased levels of cysteine and glutathione”
e1“Crude leaf extracts of these plants exhibited up to 20-fold higher SAT activity than those prepared from wild-type plants”
Claim · model-written summary
Transgenic potato leaves had elevated cysteine and glutathione levels, up to twofold higher than control plants.
- Taxon
- potatoSolanum tuberosumt0
- Organ / stage
- leavese2
- Treatment
- Expression of a bacterial serine acetyltransferaset0
- Outcome
- levels of cysteine and glutathionee2
- Direction
- highere2
- Value
- up to twofolde2
- Comparator
- control plantse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Expression of a bacterial serine acetyltransferase in transgenic potato plants leads to increased levels of cysteine and glutathione”
e2“exhibited elevated levels of cysteine and glutathione in leaves. Both were up to twofold higher than in control plants”
Claim · model-written summary
The thiol content in tubers of transgenic potato lines was unaffected.
- Taxon
- potatoSolanum tuberosumt0
- Organ / stage
- tuberse3
- Treatment
- Expression of a bacterial serine acetyltransferaset0
- Outcome
- thiol contente3
- Direction
- unaffectede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Expression of a bacterial serine acetyltransferase in transgenic potato plants leads to increased levels of cysteine and glutathione”
e3“However, the thiol content in tubers of transgenic lines was unaffected”
Claim · model-written summary
The leaf alterations had no effect on the expression of O-acetylserine(thiol)-lyase in transgenic potato.
- Taxon
- potatoSolanum tuberosumt0
- Organ / stage
- leaf tissuee4
- Treatment
- Expression of a bacterial serine acetyltransferaset0
- Gene
- O-acetylserine(thiol)-lyasee4
- Outcome
- expression of O-acetylserine(thiol)-lyasee4
- Direction
- no effecte4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Expression of a bacterial serine acetyltransferase in transgenic potato plants leads to increased levels of cysteine and glutathione”
e4“The alterations observed in leaf tissue had no effect on the expression of O-acetylserine(thiol)-lyase”
Claim · model-written summary
The transgene had only a minor effect on O-acetylserine(thiol)-lyase enzymatic activity in potato.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- Expression of a bacterial serine acetyltransferaset0
- Outcome
- enzymatic activitye5
- Direction
- minor effecte5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Expression of a bacterial serine acetyltransferase in transgenic potato plants leads to increased levels of cysteine and glutathione”
e5“Only a minor effect on its enzymatic activity was observed”
Claim · model-written summary
SAT protein from E. coli was localised to the chloroplast in transgenic potato.
- Taxon
- potatoSolanum tuberosumt0
- Gene
- E. coli SAT proteine6
- Outcome
- chloroplastic localisatione6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Expression of a bacterial serine acetyltransferase in transgenic potato plants leads to increased levels of cysteine and glutathione”
e6“The chloroplastic localisation of the E. coli SAT protein was demonstrated by determination of enzymatic activities in enriched organelle fractions”
Claim · model-written summary
Transgenic potato plants showed a high accumulation of the cysE mRNA.
- Taxon
- potatoSolanum tuberosumt0
- Gene
- cysEe7
- Outcome
- accumulation of the cysE mRNAe7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Expression of a bacterial serine acetyltransferase in transgenic potato plants leads to increased levels of cysteine and glutathione”
e7“Transgenic plants showed a high accumulation of the cysE mRNA”
The same questions in other papers
transgenic · physiology: enzyme activity · Solanum tuberosum (potato)Positive and negative results
1 paper in the same direction as this paper · 2 in the opposite direction
- positive
- positive
- negative
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.