Abstract
Etioplasts of 4.5-day-old dark-grown barley synthesize and accumulate most of the membrane and nearly all the soluble polypeptides of mature chloroplasts of light-grown seedlings. Etioplasts do not synthesize a limited set of chloroplast-encoded polypeptides which are major constituents of chloroplast thylakoid membranes: two chlorophyll apoproteins of photosystem I (68 and 65 kDa), two chlorophyll apoproteins of photosystem II (47 and 43 kDa), and a 32-kDa polypeptide which has now been identified as the psbA gene product. Throughout development in the dark, etioplasts were unable to synthesize the chlorophyll apoproteins of photosystem I and II or the psbA gene product despite the presence of significant transcript levels for psbA and psaA-psaB (encode for photosystem I chlorophyll apoproteins). Light was not required for the synthesis of ribulose bisphosphate carboxylase large subunit with the highest rate of large subunit synthesis occurring in young dark-grown seedlings. Illumination of 4.5-day-old dark-grown barley rapidly induced the synthesis of the chlorophyll apoproteins and the psbA gene product at a time when transcript levels for psbA and psaA-psaB did not increase appreciably. Therefore, during the early stages of light-induced development the synthesis of the chlorophyll apoproteins of photosystem I and psbA gene product is regulated at the translational level. With continued chloroplast development in the light, the synthesis of the chlorophyll apoproteins of photosystem I and II decline rapidly as does the synthesis of the large subunit of ribulose bisphosphate carboxylase. The decline in polypeptide synthesis correlated with a decline in rbcL and psaA-psaB transcript levels and a light-dependent decline in plastid rRNA content. In contrast, synthesis of the psbA gene product was maintained throughout light-induced chloroplast development which correlated with the maintenance of psbA transcript levels. However, light is not strictly required for psbA transcript accumulation since psbA transcript levels increased slightly with continued plastid development in dark-grown seedlings.
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Claims 11
Claim · model-written summary
Dark-grown barley etioplasts synthesize and accumulate most mature chloroplast membrane and soluble polypeptides.
- Taxon
- barley
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Hordeum vulgaree0 - Organ / stage
- Etioplastse0
- Outcome
- membrane and nearly all the soluble polypeptidese0
- Qualifier
- 4.5-day-old dark-growne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Etioplasts of 4.5-day-old dark-grown barley synthesize and accumulate most of the membrane and nearly all the soluble polypeptides of mature chloroplasts of light-grown seedlings.”
Claim · model-written summary
Dark-grown etioplasts do not synthesize photosystem I or II chlorophyll apoproteins or the psbA product despite transcripts.
- Taxon
- barleyHordeum vulgaret0
- Organ / stage
- etioplastse0
- Gene
- psbAe0
- Outcome
- unable to synthesize the chlorophyll apoproteins of photosystem I and II or the psbA gene producte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Throughout development in the dark, etioplasts were unable to synthesize the chlorophyll apoproteins of photosystem I and II or the psbA gene product despite the presence of significant transcript levels for psbA and psaA-psaB”
t0“barley seedlings”
Claim · model-written summary
Dark-grown etioplasts contain significant psbA and psaA-psaB transcript levels.
- Taxon
- barleyHordeum vulgaret0
- Gene
- psbA and psaA-psaBe0
- Outcome
- significant transcript levels for psbA and psaA-psaBe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“despite the presence of significant transcript levels for psbA and psaA-psaB”
t0“barley seedlings”
Claim · model-written summary
Ribulose bisphosphate carboxylase large-subunit synthesis did not require light and peaked in young dark-grown seedlings.
- Taxon
- barleyHordeum vulgaret0
- Gene
- ribulose bisphosphate carboxylase large subunite0
- Outcome
- large subunit synthesise0
- Direction
- highest ratee0
- Qualifier
- young dark-grown seedlingse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Light was not required for the synthesis of ribulose bisphosphate carboxylase large subunit with the highest rate of large subunit synthesis occurring in young dark-grown seedlings.”
t0“barley seedlings”
Claim · model-written summary
Illumination rapidly induced chlorophyll apoprotein and psbA product synthesis.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- Illuminatione0
- Gene
- psbAe0
- Outcome
- synthesis of the chlorophyll apoproteins and the psbA gene producte0
- Direction
- inducede0
- Comparator
- dark-growne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Illumination of 4.5-day-old dark-grown barley rapidly induced the synthesis of the chlorophyll apoproteins and the psbA gene product”
Claim · model-written summary
At initial illumination, psbA and psaA-psbB transcript levels did not rise appreciably.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- Illuminatione1
- Outcome
- transcript levels for psbA and psaA-psaBe0
- Direction
- did not increase appreciablye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transcript levels for psbA and psaA-psaB did not increase appreciably”
t0“barley seedlings”
e1“Illumination of 4.5-day-old dark-grown barley rapidly induced the synthesis of the chlorophyll apoproteins and the psbA gene product”
Claim · model-written summary
Early light-induced chlorophyll apoprotein and psbA product synthesis is regulated at translation.
- Taxon
- barleyHordeum vulgaret0
- Gene
- psbAe0
- Outcome
- synthesis of the chlorophyll apoproteins of photosystem I and psbA gene producte0
- Qualifier
- translational levele0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“during the early stages of light-induced development the synthesis of the chlorophyll apoproteins of photosystem I and psbA gene product is regulated at the translational level”
t0“barley seedlings”
Claim · model-written summary
With continued light development, photosystem I and II apoprotein synthesis and carboxylase large-subunit synthesis declined rapidly.
- Taxon
- barleyHordeum vulgaret0
- Outcome
- synthesis of the chlorophyll apoproteins of photosystem I and IIe0
- Direction
- decline rapidlye0
- Qualifier
- continued chloroplast development in the lighte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“With continued chloroplast development in the light, the synthesis of the chlorophyll apoproteins of photosystem I and II decline rapidly as does the synthesis of the large subunit of ribulose bisphosphate carboxylase.”
t0“barley seedlings”
Claim · model-written summary
Declining polypeptide synthesis correlated with declining rbcL and psaA-psaB transcripts and plastid rRNA.
- Taxon
- barleyHordeum vulgaret0
- Gene
- rbcL and psaA-psaBe0
- Outcome
- polypeptide synthesise0
- Direction
- declinee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The decline in polypeptide synthesis correlated with a decline in rbcL and psaA-psaB transcript levels and a light-dependent decline in plastid rRNA content.”
t0“barley seedlings”
Claim · model-written summary
psbA product synthesis and transcripts remained maintained during light-induced chloroplast development.
- Taxon
- barleyHordeum vulgaret0
- Gene
- psbAe0
- Outcome
- synthesis of the psbA gene producte0
- Direction
- maintainede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“synthesis of the psbA gene product was maintained throughout light-induced chloroplast development which correlated with the maintenance of psbA transcript levels”
t0“barley seedlings”
Claim · model-written summary
psbA transcripts increased slightly with continuing dark plastid development.
- Taxon
- barleyHordeum vulgaret0
- Gene
- psbAe0
- Outcome
- psbA transcript levelse0
- Direction
- increased slightlye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“psbA transcript levels increased slightly with continued plastid development in dark-grown seedlings”
t0“barley seedlings”
The same questions in other papers
light · molecular: expression · Hordeum vulgare (barley)Positive and negative results
19 papers in the same direction as this paper · 4 in the opposite direction
- positive
- no effect
- no effect
20 papers more in this group
See all 24 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.