Abstract
We characterized the photobiology of light-activated chloroplast transcription and transcript abundance in mature primary leaves by using the following two systems: transplastomic promoter-reporter gene fusions in tobacco (Nicotiana tabacum), and phytochrome (phyA, phyB, and hy2) and cryptochrome (cry1) mutants of Arabidopsis. In both dicots, blue light and UV-A radiation were the major signals that activated total chloroplast and psbA, rbcL, and 16S rrn transcription. In contrast, transcription activities in plants exposed to red and far-red light were 30% to 85% less than in blue light/UV-A, depending on the gene and plant species. Total chloroplast, psbA, and 16S rrn transcription were 60% to 80% less in the Arabidopsis phyA mutant exposed to blue light/UV-A relative to wild type, thus definitively linking phyA signaling to these photoresponses. To our knowledge, the major role of phyA in mediating the blue light/UV-A photoresponses is a new function for phyA in chloroplast biogenesis at this stage of leaf development. Although rbcL expression in plants exposed to UV-A was 50% less in the phyA mutant relative to wild type, blue light-induced rbcL expression was not significantly affected in the phyA, phyB, and cry1 mutants. However, rbcL expression in blue light was 60% less in the phytochrome chromophore mutant, hy2, relative to wild type, indicating that another phytochrome species (phyC, D, or E) was involved in blue light-induced rbcL transcription. Therefore, at least two different phytochromes, as well as phytochrome-independent photosensory pathways, mediated blue light/UV-A-induced transcription of chloroplast genes in mature leaves.
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Claims 8
Claim · model-written summary
Blue light and UV-A activated chloroplast and three gene transcription targets in both dicots.
- Taxon
- Arabidopsis
Arabidopsist0 - Treatment
- blue light and UV-A radiatione0
- Outcome
- total chloroplast and psbA, rbcL, and 16S rrn transcriptione0
- Direction
- activatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In both dicots, blue light and UV-A radiation were the major signals that activated total chloroplast and psbA, rbcL, and 16S rrn transcription”
t0“mutants of Arabidopsis”
Claim · model-written summary
Red and far red light yielded 30 to 85 percent less transcription than blue light or UV-A.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- red and far-red lighte0
- Outcome
- transcription activitiese0
- Direction
- lesse0
- Value
- 30% to 85%e0
- Comparator
- blue light/UV-Ae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transcription activities in plants exposed to red and far-red light were 30% to 85% less than in blue light/UV-A”
t0“mutants of Arabidopsis”
Claim · model-written summary
Arabidopsis phyA mutants had 60 to 80 percent lower total chloroplast, psbA and 16S rrn transcription under blue light or UV-A.
- Taxon
- ArabidopsisArabidopsise0
- Material
- phyA mutante0
- Treatment
- blue light/UV-Ae0
- Gene
- phyAe0
- Outcome
- Total chloroplast, psbA, and 16S rrn transcriptione0
- Direction
- lesse0
- Value
- 60% to 80%e0
- Comparator
- wild typee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total chloroplast, psbA, and 16S rrn transcription were 60% to 80% less in the Arabidopsis phyA mutant exposed to blue light/UV-A relative to wild type”
Claim · model-written summary
Under UV-A, phyA mutants had 50 percent less rbcL expression.
- Taxon
- ArabidopsisArabidopsist0
- Material
- phyA mutante0
- Treatment
- UV-Ae0
- Gene
- rbcLe0
- Outcome
- rbcL expressione0
- Direction
- lesse0
- Value
- 50%e0
- Comparator
- wild typee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“rbcL expression in plants exposed to UV-A was 50% less in the phyA mutant relative to wild type”
t0“mutants of Arabidopsis”
Claim · model-written summary
Blue light rbcL expression was not significantly affected in phyA, phyB, and cry1 mutants.
- Taxon
- ArabidopsisArabidopsist0
- Material
- phyA, phyB, and cry1 mutantse0
- Treatment
- blue lighte0
- Gene
- rbcLe0
- Outcome
- rbcL expressione0
- Direction
- not significantly affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“blue light-induced rbcL expression was not significantly affected in the phyA, phyB, and cry1 mutants”
t0“mutants of Arabidopsis”
Claim · model-written summary
Blue light rbcL expression in hy2 mutants was 60 percent below wild type.
- Taxon
- ArabidopsisArabidopsist0
- Material
- hy2e0
- Treatment
- blue lighte0
- Gene
- rbcLe0
- Outcome
- rbcL expressione0
- Direction
- lesse0
- Value
- 60%e0
- Comparator
- wild typee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“rbcL expression in blue light was 60% less in the phytochrome chromophore mutant, hy2, relative to wild type”
t0“mutants of Arabidopsis”
Claim · model-written summary
The authors infer another phytochrome is involved in blue light rbcL transcription.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- phyC, D, or Ee0
- Outcome
- blue light-induced rbcL transcriptione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“another phytochrome species (phyC, D, or E) was involved in blue light-induced rbcL transcription”
t0“mutants of Arabidopsis”
Claim · model-written summary
The authors infer multiple phytochromes and independent sensory pathways mediate chloroplast transcription.
- Taxon
- ArabidopsisArabidopsist0
- Outcome
- transcription of chloroplast genese0
- Qualifier
- at least two different phytochromes, as well as phytochrome-independent photosensory pathwayse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“at least two different phytochromes, as well as phytochrome-independent photosensory pathways, mediated blue light/UV-A-induced transcription of chloroplast genes in mature leaves”
t0“mutants of Arabidopsis”
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See all 80 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.