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Ove Nilsson Ove Nilsson Ume, Sweden Ume, Sweden Recipient of the - - PowerPoint PPT Presentation
Ove Nilsson Ove Nilsson Ume, Sweden Ume, Sweden Recipient of the - - PowerPoint PPT Presentation
Ove Nilsson Ove Nilsson Ume, Sweden Ume, Sweden Recipient of the 2007 Marcus Wallenberg Recipient of the 2007 Marcus Wallenberg Prize Prize Regulation of Flowering in Trees - Translation into Tree Growth and Development Ove Nilsson
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Annuals and Perennials
Arabidopsis Aspen
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Daylength is Critical, Not Temperature
16:00 9:00
Garner & Allard 1920
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The Molecular Basis for the Coincidence Model
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The Molecular Basis for the Flowering Signal (Florigen)
FT PROTEIN FT Protein FT RNA FD Protein FD Protein + CONSTANS RNA CONSTANS Protein
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The Populus Genome
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Populus FT/TFL Homologues
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TFL1 and FT: Functional Conservation
35S::PtTFL1 WT 35S::PtFT1
Böhlenius et al.. 2006. Science 312, 1040-1043
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Expression of PtFT1 Increases With Age
Time (years)
2 4 6 8 4 3 2 1
Time (years) Time (years)
MAY JUNE
pttFT1/18Sx10
Samples from young shoots of a Poplar clone planted yearly in Oregon Flower initiation
Böhlenius et al., Science 2006
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35S::PtFT1 Poplars are Extremely Early Flowering!
Flowers 4 weeks after transformation!
Böhlenius et al.. 2006. Science 312, 1040-1043
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35S::PtFT1 Poplars Produce Catkins
6 month old plants
Böhlenius et al.. 2006. Science 312, 1040-1043
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35S::PtFT1 Aspens Have Normal Flowers
35S::PtFT1 Catkin 35S::PtFT1 Male flower
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Bud Set and Dormancy is a Short Day Response in Aspen Trees
WT 6 weeks of short days
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35S::PtFT1 Inhibits Short Day-Induced Growth Cessation and Bud Set
LD 32 SD 64 SD 5 days 5°C 35S::PtFT1 WT
Böhlenius et al.. 2006. Science 312, 1040-1043
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PtCO2 expression
Time (hours)
LD SD
pttCO2/18Sx10
Böhlenius et al., Science 2006
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PtFT1 expression
LD SD
Time (hours)
pttFT1/18Sx10
Böhlenius et al., Science 2006
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PtFT1 RNAi Induces Premature Bud Set
Böhlenius et al., Science 2006
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PtFT1 Controls Dual Aspects of Perennial Growth Behaviour
Induction of reproductive phase Growth cessation and bud set
Time (years)
2 4 6 8 4 3 2 1
Time (years) Time (years)
MAY JUNE
Time (hours)
pttFT1/18Sx10
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Seasonal Regulation of PtFT1
30 year old Populus tremula growing in Umeå (64°N) 21 hrs critical daylength?
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Critical Daylength for Growth Cessation and Bud Set
Umeå 63°N: 21 hrs Ronneby 56°N: 17 hrs Stockholm 59°N: 19 hrs Dresden 50°N: 15 hrs
Provenances of European Aspen (Populus tremula)
Böhlenius et al., Science 2006
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At the Critical Daylength PtFT1 is Down-Regulated
(21 hrs) (19 hrs) (17 hrs) (15 hrs)
Böhlenius et al., Science 2006
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Could the Phase of CO mRNA Oscillation be Setting the Critical Daylength?
16 hrs 12 hrs 8 hrs
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(21 hrs) (19 hrs) (17 hrs) (15 hrs)
The Phase of CO mRNA Oscillation Predicts the Critical Daylength
Böhlenius et al.. 2006. Science 312, 1040-1043
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Annuals and Perennials
Arabidopsis Aspen
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Tree secondary growth produces wood Tree secondary growth produces wood
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Jeanette Nilsson
Development
Organization of the Vascular Meristem Organization of the Vascular Meristem
Phloem mother cells Xylem mother cells Cambium
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Primary xylem
Jeanette Nilsson
Expression in cells of provascular tissue Expression in cells of provascular tissue
Pith CambiumPrimary Phloem
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Jeanette Nilsson
C & D A & B
Pt t HB3 expression defines provascular
development
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Pt t HB3 RNAi affects secondary growth Pt t HB3 RNAi affects secondary growth
Jeanette Nilsson
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Jeanette Nilsson
Reduced growth rate of xylem Reduced growth rate of xylem
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Jeanette Nilsson
Reduced activity in the cambium Reduced activity in the cambium
T89 PttHB3 RNAi
Phloem Xylem
Cambium
Ph Xm
C
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Conclusions Conclusions
PtFT1 controls the length of the juvenile phase in trees
- Breeding tool! Prevented flowering!
PtFT1 controls the length of the growing season in trees
- Adaptation to new climates?
- PttHB3 controls the activity (and identity?) of the vascular
cambium and hence secondary growth in trees
- The gene that allows a tree to ”grow as a tree”. Tool to increase wood production?
This constitutes three of the most important processes associated with the ”tree life strategy” ”Tailor-made trees”
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Acknowledgements Acknowledgements
Tree flowering and growth cessation
Henrik Böhlenius Maria Eriksson Stefan Jansson Hans Hönicka Amy Brunner Steve Strauss
PttHB3 and vascular cambium identity
Jeanette Nilsson Bo Zheng Göran Sandberg