Abstract
The effect of O-methyltransferase (OMT) cDNA modulation on cell wall composition, ultrastructure and rumen degradability was measured on transgenic tobacco (Nicotiana tabacum). The expression of OMT cDNA in antisense orientation (AS) inhibited OMT activity by 92% whereas expression of sense constructs led to plants either co-suppressed (CS, 98% inhibition) or overexpressing OMT activity. The cell wall residues of stems were analysed for lignin content, products of nitrobenzene oxidation (NBO) and polysaccharide content. Degradability was determined by a cellulase method. Sections of stem were stained by acid phloroglucinol and Mäule reactant. Stem samples were incubated in the rumen for 8, 24 and 48 h and observed by scanning electron microscopy (SEM). Compared to controls, OMT-depleted stems showed decreased hemicellulose content but unchanged lignin content. In contrast, syringyl units decreased by 40 and 90% in AS and CS samples respectively and NBO content followed a similar trend. Dry matter cellulase degradability was significantly improved by 3·5 and 5·6 percentage units in AS and CS samples respectively. SEM showed a greater bacterial colonisation in these samples and indicated a higher rate of rumen degradability in CS tissues than in controls. Overexpressing plants had a composition and a degradability similar to that of controls. For all the plants studied, the improvements in dry matter degradability were closely linked to the syringyl to guaiacyl ratio or to the NBO content. The modifications observed in down-regulated tobacco were similar to those produced by bm3 maize mutation, but without lignin decrease. Genetic modifications should therefore be considered for improving forage digestibility.
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Claims 18
Claim · model-written summary
Antisense OMT inhibited activity by 92%.
- Taxon
- tobacco
Nicotiana tabacume0 - Treatment
- antisense orientation (AS)e1
- Gene
- OMTe1
- Outcome
- OMT activitye1
- Direction
- inhibitede1
- Value
- 92%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“The expression of OMT cDNA in antisense orientation (AS) inhibited OMT activity by 92%”
Claim · model-written summary
Co-suppression inhibited OMT activity by 98%.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- sense constructse1
- Outcome
- OMT activitye2
- Direction
- inhibitione1
- Value
- 98%e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“expression of sense constructs led to plants either co-suppressed (CS, 98% inhibition)”
e2“or overexpressing OMT activity”
Claim · model-written summary
Sense constructs also produced OMT overexpressing plants.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- sense constructse1
- Outcome
- OMT activitye1
- Direction
- overexpressinge1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“expression of sense constructs led to plants either co-suppressed (CS, 98% inhibition) or overexpressing OMT activity”
Claim · model-written summary
OMT-depleted stems had decreased hemicellulose content.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- OMT-depletede1
- Outcome
- hemicellulose contente1
- Direction
- decreasede1
- Comparator
- controlse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“Compared to controls, OMT-depleted stems showed decreased hemicellulose content but unchanged lignin content”
Claim · model-written summary
OMT-depleted stems had unchanged lignin content.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- OMT-depletede1
- Outcome
- lignin contente1
- Direction
- unchangede1
- Comparator
- controlse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“Compared to controls, OMT-depleted stems showed decreased hemicellulose content but unchanged lignin content”
Claim · model-written summary
Syringyl units decreased by 40% in AS samples.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“syringyl units decreased by 40 and 90% in AS and CS samples respectively”
Claim · model-written summary
Syringyl units decreased by 90% in CS samples.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“syringyl units decreased by 40 and 90% in AS and CS samples respectively”
Claim · model-written summary
NBO content followed the syringyl decline.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- AS and CS samplese2
- Outcome
- NBO contente1
- Direction
- decreasede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“NBO content followed a similar trend”
e2“syringyl units decreased by 40 and 90% in AS and CS samples respectively”
Claim · model-written summary
AS increased dry matter cellulase degradability by 3·5 percentage units.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- ASe1
- Outcome
- Dry matter cellulase degradabilitye1
- Direction
- improvede1
- Value
- 3·5e1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“Dry matter cellulase degradability was significantly improved by 3·5 and 5·6 percentage units in AS and CS samples respectively”
Claim · model-written summary
CS increased dry matter cellulase degradability by 5·6 percentage units.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- CSe1
- Outcome
- Dry matter cellulase degradabilitye1
- Direction
- improvede1
- Value
- 5·6 percentage unitse1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“Dry matter cellulase degradability was significantly improved by 3·5 and 5·6 percentage units in AS and CS samples respectively”
Claim · model-written summary
SEM showed greater bacterial colonisation in OMT-depleted stems.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- OMT-depletede2
- Interactor
- bacteriale1other
- Outcome
- bacterial colonisatione1
- Direction
- greatere1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“SEM showed a greater bacterial colonisation in these samples”
e2“OMT-depleted stems”
Claim · model-written summary
CS tissues had a higher rate of rumen degradability than controls.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- CSe1
- Outcome
- rate of rumen degradabilitye1
- Direction
- highere1
- Comparator
- controlse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“a higher rate of rumen degradability in CS tissues than in controls”
Claim · model-written summary
Overexpressing plants had composition similar to controls.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- Overexpressinge1
- Outcome
- compositione1
- Direction
- similare1
- Comparator
- controlse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“Overexpressing plants had a composition and a degradability similar to that of controls”
Claim · model-written summary
Overexpressing plants had degradability similar to controls.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- Overexpressinge1
- Outcome
- degradabilitye1
- Direction
- similare1
- Comparator
- controlse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“Overexpressing plants had a composition and a degradability similar to that of controls”
Claim · model-written summary
Dry matter degradability improvements were linked to syringyl to guaiacyl ratio.
- Taxon
- tobaccoNicotiana tabacume0
- Compound
- syringyl to guaiacyl ratioe1
- Outcome
- improvements in dry matter degradabilitye1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“improvements in dry matter degradability were closely linked to the syringyl to guaiacyl ratio or to the NBO content”
Claim · model-written summary
Dry matter degradability improvements were linked to NBO content.
- Taxon
- tobaccoNicotiana tabacume0
- Compound
- NBO contente1
- Outcome
- improvements in dry matter degradabilitye1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“improvements in dry matter degradability were closely linked to the syringyl to guaiacyl ratio or to the NBO content”
Claim · model-written summary
Modifications in down-regulated tobacco resembled bm3 maize mutation without reduced lignin.
- Taxon
- tobaccoNicotiana tabacume0
- Outcome
- modificationse0
- Qualifier
- without lignin decreasee0
- Comparator
- bm3 maize mutatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The modifications observed in down-regulated tobacco were similar to those produced by bm3 maize mutation, but without lignin decrease”
Claim · model-written summary
The authors recommend genetic modification to improve forage digestibility.
- Taxon
- tobaccoNicotiana tabacume0
- Outcome
- improving forage digestibilitye1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic tobacco (Nicotiana tabacum)”
e1“Genetic modifications should therefore be considered for improving forage digestibility”
The same questions in other papers
loss of function · growth · Nicotiana tabacum (tobacco)Positive and negative results
4 papers in the same direction as this paper · 34 in the opposite direction
- positive
- negative
- negative
35 papers more in this group
See all 39 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.