Abstract
The time course of ADP-glucose pyrophosphorylase activity and of starch accumulation rate measured in grain, from pollination to maturity, in Zea mays L. plants grown outdoors, was coincident for 2 years. No such correlation was observed in the adjacent leaf, which, furthermore, presented large year-to-year differences in starch accumulation pattern. Analysis of the expression of ADP-glucose synthase at the protein levels, using antibodies directed against the Bt2 or Sh2 subunits, established that the variation of activity in the grain was explained by parallel changes in the content of both subunits. The cDNA for Bt2 and Sh2 subunits were used as probes to quantify the corresponding messenger. In grain, the time course of Bt2 and Sh2 mRNA accumulation anticipated, with a similar pattern, the specific peptide variations, which suggests a transcriptional control of expression. By contrast, the control of leaf activity by protein content was less obvious than in the grain, and changes in leaf enzyme specific activity were suggested during the first 20 d after pollination. A clone homologous to the grain Bt2 subunit cDNA was isolated from a maize leaf cDNA library, and a sequence comparison showed that the leaf clone (L2) was a partial cDNA representing one-third of the mature peptide. A 97% homology was observed between Bt2 and L2 in their coding region, but homology was poor in the 3' noncoding border. This result demonstrates that Bt2 and L2 arise from different genes presenting a tissue-specific expression pattern and provides an explanation for the earlier reported differences between leaf and grain in the size of peptide and mRNA for the Bt2-homologous subunit.
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Claims 11
Claim · model-written summary
Maize grain enzyme activity and starch accumulation rate coincided for two years from pollination to maturity outdoors.
- Organ / stage
- graine0
- Gene
- ADP-glucose pyrophosphorylasee0
- Outcome
- starch accumulation ratee0
- Value
- 2 yearse0
- Setting
- outdoorse0
Zea maysNot reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The time course of ADP-glucose pyrophosphorylase activity and of starch accumulation rate measured in grain, from pollination to maturity, in Zea mays L. plants grown outdoors, was coincident for 2 years.”
Claim · model-written summary
The adjacent maize leaf showed no corresponding correlation between enzyme activity and starch accumulation.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No such correlation was observed in the adjacent leaf, which, furthermore, presented large year-to-year differences in starch accumulation pattern.”
t0“Zea mays L.”
Claim · model-written summary
Maize leaves showed large year-to-year differences in starch accumulation pattern.
- Organ / stage
- adjacent leafe0
- Outcome
- starch accumulation patterne0
- Qualifier
- large year-to-year differencese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No such correlation was observed in the adjacent leaf, which, furthermore, presented large year-to-year differences in starch accumulation pattern.”
t0“Zea mays L.”
Claim · model-written summary
Parallel changes in Bt2 and Sh2 protein content explained maize grain enzyme activity variation.
- Organ / stage
- graine0
- Gene
- Bt2 or Sh2 subunitse0
- Outcome
- variation of activitye0
- Qualifier
- parallel changes in the content of both subunitse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Analysis of the expression of ADP-glucose synthase at the protein levels, using antibodies directed against the Bt2 or Sh2 subunits, established that the variation of activity in the grain was explained by parallel changes in the content of both subunits.”
t0“Zea mays L.”
Claim · model-written summary
Bt2 and Sh2 mRNA changes preceded similar peptide changes in maize grain, suggesting transcriptional control.
- Organ / stage
- graine0
- Gene
- Bt2 and Sh2e0
- Outcome
- specific peptide variationse0
- Qualifier
- transcriptional control of expressione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In grain, the time course of Bt2 and Sh2 mRNA accumulation anticipated, with a similar pattern, the specific peptide variations, which suggests a transcriptional control of expression.”
t0“Zea mays L.”
Claim · model-written summary
Protein-content control of maize leaf enzyme activity was less obvious than in grain.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“By contrast, the control of leaf activity by protein content was less obvious than in the grain, and changes in leaf enzyme specific activity were suggested during the first 20 d after pollination.”
t0“Zea mays L.”
Claim · model-written summary
Changes in maize leaf enzyme specific activity were suggested in the first 20 days after pollination.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“changes in leaf enzyme specific activity were suggested during the first 20 d after pollination.”
t0“Zea mays L.”
Claim · model-written summary
A maize leaf clone L2 homologous to Bt2 was isolated and represented one-third of the mature peptide.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A clone homologous to the grain Bt2 subunit cDNA was isolated from a maize leaf cDNA library, and a sequence comparison showed that the leaf clone (L2) was a partial cDNA representing one-third of the mature peptide.”
Claim · model-written summary
Bt2 and L2 had 97% coding-region homology.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A 97% homology was observed between Bt2 and L2 in their coding region, but homology was poor in the 3' noncoding border.”
t0“Zea mays L.”
Claim · model-written summary
Bt2 and L2 had poor homology at the 3′ noncoding border.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A 97% homology was observed between Bt2 and L2 in their coding region, but homology was poor in the 3' noncoding border.”
t0“Zea mays L.”
Claim · model-written summary
Bt2 and L2 arise from distinct maize genes with tissue-specific expression, explaining leaf–grain peptide and mRNA size differences.
- Gene
- Bt2 and L2e0
- Outcome
- differences between leaf and grain in the size of peptide and mRNAe0
- Qualifier
- different genes presenting a tissue-specific expression patterne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This result demonstrates that Bt2 and L2 arise from different genes presenting a tissue-specific expression pattern and provides an explanation for the earlier reported differences between leaf and grain in the size of peptide and mRNA for the Bt2-homologous subunit.”
t0“Zea mays L.”