Abstract
Exo-galactanase/beta-galactosidase (EC 3.2.1.23) activity is thought to be responsible for the loss of galactosyl residues from the cell walls of ripening tomatoes. Transgenic tomato plants (Lycopersicon esculentum Mill cv. Ailsa Craig) with reduced exo-galactanase/beta-galactosidase mRNA were generated to test this hypothesis and to investigate the role of the enzyme in fruit softening. A previously identified tomato beta-galactosidase cDNA clone, TBG1, was used in the experiments. Heterologous expression of the clone in yeast demonstrated that TBG1 could release galactosyl residues from tomato cell wall galactans. Transgenic plants showed a reduction in TBG1 mRNA to 10% of normal levels in the ripening fruits. However, despite the reduction in message, total beta-galactosidase and exo-galactanase activities were unaffected. Furthermore, there was no apparent effect on levels of cell wall galactosyl residues when compared with the control. It was concluded that during the ripening of tomato fruits a family of beta-galactosidases capable of degrading cell wall galactans are active and down-regulation of TBG1 message to 10% was insufficient to alter the degree of galactan degradation.
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Claims 5
Claim · model-written summary
TBG1 expressed in yeast released galactosyl residues from tomato cell wall galactans.
- Taxon
- tomato
Solanum lycopersicume0 - Gene
- TBG1e0
- Outcome
- release galactosyl residues from tomato cell wall galactanse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Heterologous expression of the clone in yeast demonstrated that TBG1 could release galactosyl residues from tomato cell wall galactans.”
Claim · model-written summary
Transgenic tomato ripening fruit had TBG1 mRNA reduced to 10% of normal.
- Taxon
- tomatoSolanum lycopersicumt0
- Organ / stage
- ripening fruitse0
- Gene
- TBG1e0
- Outcome
- TBG1 mRNAe0
- Direction
- reductione0
- Value
- 10%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transgenic plants showed a reduction in TBG1 mRNA to 10% of normal levels in the ripening fruits.”
t0“tomato fruits”
Claim · model-written summary
Total beta-galactosidase and exo-galactanase activities were unaffected despite reduced TBG1 message.
- Taxon
- tomatoSolanum lycopersicumt0
- Gene
- beta-galactosidasee0
- Outcome
- total beta-galactosidase and exo-galactanase activitiese0
- Direction
- unaffectede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“despite the reduction in message, total beta-galactosidase and exo-galactanase activities were unaffected.”
t0“tomato fruits”
Claim · model-written summary
Cell wall galactosyl residue levels did not apparently differ from control.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- down-regulation of TBG1 message to 10%e1
- Outcome
- levels of cell wall galactosyl residuese0
- Direction
- no apparent effecte0
- Comparator
- the controle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there was no apparent effect on levels of cell wall galactosyl residues when compared with the control.”
t0“tomato fruits”
e1“down-regulation of TBG1 message to 10%”
Claim · model-written summary
The authors concluded that a family of beta-galactosidases degrades cell wall galactans during tomato ripening.
- Taxon
- tomatoSolanum lycopersicume0
- Organ / stage
- fruitse0
- Gene
- beta-galactosidasese0
- Outcome
- degrading cell wall galactanse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“during the ripening of tomato fruits a family of beta-galactosidases capable of degrading cell wall galactans are active”
The same questions in other papers
loss of function · cytology · Solanum lycopersicum (tomato)Positive and negative results
13 papers in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
- negative
11 papers more in this group
See all 15 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.