Abstract
We have previously characterized RbcS antisense DNA mutants of tobacco that have drastic reductions in their content of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; S.R. Rodermel, M.S. Abbott, L. Bogorad [1988] Cell 55: 673-681). In this report we examine the impact of Rubisco loss on photosynthesis during tobacco (Nicotiana tabacum) leaf development. Photosynthetic capacities are depressed in the antisense leaves, but the patterns of change in photosynthetic rates during the development of these leaves are similar to those in wild-type plants: after attaining a maximum in young leaves, photosynthetic capacities undergo a prolonged senescence decline in older leaves. The alterations in photosynthetic capacities in both the wild type and mutant are closely correlated with changes in Rubisco activity and content. During wild-type leaf development, Rubisco accumulation is regulated by coordinate changes in RbcS and rbcL transcript accumulation, whereas in the antisense leaves, Rubisco content is a function of RbcS, but not rbcL, transcript abundance. This indicates that large subunit protein production is controlled posttranscriptionally in the mutants. The antisense leaves accumulate near-normal levels of chlorophyll and representative photosynthetic proteins throughout development, suggesting that photosynthetic gene expression is not feedback regulated by Rubisco abundance. Considered together, the data in this paper indicate that leaf developmental programs are generally insensitive to sharp reductions in Rubisco content and emphasize the metabolic plasticity of plant cells in achieving optimal photosynthetic rates.
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Claims 9
Claim · model-written summary
Photosynthetic capacities are depressed in RbcS antisense tobacco leaves.
- Taxon
- tobacco
Nicotiana tabacume0 - Material
- RbcS antisense DNA mutantse2
- Outcome
- Photosynthetic capacitiese1
- Direction
- depressede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco (Nicotiana tabacum) leaf development”
e1“Photosynthetic capacities are depressed in the antisense leaves”
e2“We have previously characterized RbcS antisense DNA mutants of tobacco”
Claim · model-written summary
Photosynthetic rate patterns during leaf development in antisense mutants are similar to those of wild-type plants.
- Taxon
- tobaccoNicotiana tabacume0
- Outcome
- patterns of change in photosynthetic ratese3
- Direction
- similare3
- Comparator
- wild-type plantse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco (Nicotiana tabacum) leaf development”
e3“the patterns of change in photosynthetic rates during the development of these leaves are similar to those in wild-type plants”
Claim · model-written summary
Alterations in photosynthetic capacities are closely correlated with changes in Rubisco activity and content.
- Taxon
- tobaccoNicotiana tabacume0
- Gene
- Rubiscoe4
- Outcome
- alterations in photosynthetic capacitiese4
- Direction
- closely correlatede4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco (Nicotiana tabacum) leaf development”
e4“The alterations in photosynthetic capacities in both the wild type and mutant are closely correlated with changes in Rubisco activity and content”
Claim · model-written summary
In antisense leaves, Rubisco content is a function of RbcS transcript abundance but not of rbcL transcript abundance.
- Taxon
- tobaccoNicotiana tabacume0
- Gene
- RbcSe5
- Outcome
- Rubisco contente5
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco (Nicotiana tabacum) leaf development”
e5“Rubisco content is a function of RbcS, but not rbcL, transcript abundance”
Claim · model-written summary
In wild-type leaves, Rubisco accumulation is regulated by coordinate changes in RbcS and rbcL transcript accumulation.
- Taxon
- tobaccoNicotiana tabacume0
- Gene
- RbcS and rbcLe6
- Outcome
- Rubisco accumulatione6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco (Nicotiana tabacum) leaf development”
e6“Rubisco accumulation is regulated by coordinate changes in RbcS and rbcL transcript accumulation”
Claim · model-written summary
Large subunit protein production is controlled posttranscriptionally in the antisense mutants.
- Taxon
- tobaccoNicotiana tabacume0
- Outcome
- large subunit protein productione7
- Qualifier
- controlled posttranscriptionallye7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco (Nicotiana tabacum) leaf development”
e7“This indicates that large subunit protein production is controlled posttranscriptionally in the mutants”
Claim · model-written summary
Antisense leaves accumulate near-normal levels of chlorophyll and representative photosynthetic proteins throughout development.
- Taxon
- tobaccoNicotiana tabacume0
- Outcome
- chlorophyll and representative photosynthetic proteinse1
- Qualifier
- near-normal levelse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco (Nicotiana tabacum) leaf development”
e1“The antisense leaves accumulate near-normal levels of chlorophyll and representative photosynthetic proteins throughout development”
Claim · model-written summary
Photosynthetic gene expression is not feedback regulated by Rubisco abundance.
- Taxon
- tobaccoNicotiana tabacume0
- Outcome
- photosynthetic gene expressione1
- Qualifier
- not feedback regulated by Rubisco abundancee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco (Nicotiana tabacum) leaf development”
e1“suggesting that photosynthetic gene expression is not feedback regulated by Rubisco abundance”
Claim · model-written summary
Leaf developmental programs are generally insensitive to sharp reductions in Rubisco content.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- sharp reductions in Rubisco contente1
- Outcome
- leaf developmental programse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tobacco (Nicotiana tabacum) leaf development”
e1“leaf developmental programs are generally insensitive to sharp reductions in Rubisco content”