Abstract
CONSTANS (CO) is an important flowering-time gene in the photoperiodic flowering pathway of annual Arabidopsis thaliana in which overexpression of CO induces early flowering, whereas mutations in CO cause delayed flowering. The closest homologs of CO in woody perennial poplar (Populus spp.) are CO1 and CO2. A previous report showed that the CO2/FLOWERING LOCUS T1 (FT1) regulon controls the onset of reproduction in poplar, similar to what is seen with the CO/FLOWERING LOCUS T (FT) regulon in Arabidopsis. The CO2/FT1 regulon was also reported to control fall bud set. Our long-term field observations show that overexpression of CO1 and CO2 individually or together did not alter normal reproductive onset, spring bud break, or fall dormancy in poplar, but did result in smaller trees when compared with controls. Transcripts of CO1 and CO2 were normally most abundant in the growing season and rhythmic within a day, peaking at dawn. Our manipulative experiments did not provide evidence for transcriptional regulation being affected by photoperiod, light intensity, temperature, or water stress when transcripts of CO1 and CO2 were consistently measured in the morning. A genetic network analysis using overexpressing trees, microarrays, and computation demonstrated that a majority of functionally known genes downstream of CO1 and CO2 are associated with metabolic processes, which could explain their effect on tree size. In conclusion, the function of CO1 and CO2 in poplar does not appear to overlap with that of CO from Arabidopsis, nor do our data support the involvement of CO1 and CO2 in spring bud break or fall bud set.
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Claims 9
Claim · model-written summary
In long-term field observations, overexpression of CO1 and CO2 individually or together did not alter normal reproductive onset, spring bud break or fall dormancy in poplar.
- Treatment
- overexpression of CO1 and CO2 individually or togethere0
- Gene
- CO1 and CO2e0
- Outcome
- normal reproductive onset, spring bud break, or fall dormancye0
- Direction
- did not altere0
- Setting
- fielde0
PopulusNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Our long-term field observations show that overexpression of CO1 and CO2 individually or together did not alter normal reproductive onset, spring bud break, or fall dormancy in poplar”
Claim · model-written summary
Overexpression of CO1 and CO2 resulted in smaller poplar trees compared with controls.
- Treatment
- overexpression of CO1 and CO2e0
- Gene
- CO1 and CO2e0
- Outcome
- smaller treese0
- Direction
- smallere0
- Comparator
- controlse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“overexpression of CO1 and CO2 individually or together did not alter normal reproductive onset, spring bud break, or fall dormancy in poplar, but did result in smaller trees when compared with controls”
Claim · model-written summary
Transcripts of CO1 and CO2 were normally most abundant in the growing season in poplar.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transcripts of CO1 and CO2 were normally most abundant in the growing season”
t0“Woody Perennial Poplar”
Claim · model-written summary
Transcripts of CO1 and CO2 were rhythmic within a day, peaking at dawn, in poplar.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transcripts of CO1 and CO2 were normally most abundant in the growing season and rhythmic within a day, peaking at dawn”
t0“Woody Perennial Poplar”
Claim · model-written summary
Manipulative experiments gave no evidence that CO1 and CO2 transcriptional regulation was affected by photoperiod, light intensity or temperature in poplar.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Our manipulative experiments did not provide evidence for transcriptional regulation being affected by photoperiod, light intensity, temperature, or water stress”
t0“Woody Perennial Poplar”
Claim · model-written summary
Manipulative experiments gave no evidence that CO1 and CO2 transcriptional regulation was affected by water stress in poplar.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Our manipulative experiments did not provide evidence for transcriptional regulation being affected by photoperiod, light intensity, temperature, or water stress”
t0“Woody Perennial Poplar”
Claim · model-written summary
A genetic network analysis of overexpressing trees showed that a majority of functionally known genes downstream of CO1 and CO2 are associated with metabolic processes.
- Gene
- CO1 and CO2e0
- Outcome
- majority of functionally known genes downstream of CO1 and CO2 are associated with metabolic processese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A genetic network analysis using overexpressing trees, microarrays, and computation demonstrated that a majority of functionally known genes downstream of CO1 and CO2 are associated with metabolic processes”
t0“Woody Perennial Poplar”
Claim · model-written summary
The association of downstream genes with metabolic processes could explain the effect of CO1 and CO2 overexpression on tree size.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a majority of functionally known genes downstream of CO1 and CO2 are associated with metabolic processes, which could explain their effect on tree size”
t0“Woody Perennial Poplar”
Claim · model-written summary
The authors conclude that the function of CO1 and CO2 in poplar does not appear to overlap with that of CO from Arabidopsis.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the function of CO1 and CO2 in poplar does not appear to overlap with that of CO from Arabidopsis”
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