Ove Nilsson Ove Nilsson Ume, Sweden Ume, Sweden Recipient of the - PowerPoint PPT Presentation

Ove Nilsson Ove Nilsson Umeå, Sweden Umeå, 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 Umeå Plant Science Centre Swedish University of Agricultural Sciences

Aspen Annuals and Perennials Arabidopsis

9:00 Garner & Allard 1920 Daylength is Critical, Not Temperature 16:00

The Molecular Basis for the Coincidence Model

The Molecular Basis for the Flowering Signal (Florigen) FD Protein + FD FT Protein CONSTANS RNA Protein FT RNA CONSTANS Protein FT PROTEIN

The Populus Genome

Populus FT / TFL Homologues

TFL1 and FT : Functional Conservation WT 35S::PtTFL1 35S::PtFT1 Böhlenius et al. . 2006. Science 312, 1040-1043

Expression of PtFT1 Increases With Age Flower initiation 4 pttFT1/18Sx10 3 MAY JUNE 2 1 0 0 2 4 6 8 Time (years) Time (years) Time (years) Samples from young shoots of a Poplar clone planted yearly in Oregon Böhlenius et al., Science 2006

35S::PtFT1 Poplars are Extremely Early Flowering! Flowers 4 weeks after transformation! Böhlenius et al. . 2006. Science 312, 1040-1043

35S::PtFT1 Poplars Produce Catkins 6 month old plants Böhlenius et al. . 2006. Science 312, 1040-1043

35S::PtFT1 Aspens Have Normal Flowers 35S::PtFT1 Catkin 35S::PtFT1 Male flower

Bud Set and Dormancy is a Short Day Response in Aspen Trees WT 6 weeks of short days

35S::PtFT1 Inhibits Short Day-Induced Growth Cessation and Bud Set 35S::PtFT1 WT LD 32 SD 64 SD 5 days 5°C Böhlenius et al. . 2006. Science 312, 1040-1043

PtCO2 expression pttCO2/18Sx10 LD SD Time (hours) Böhlenius et al., Science 2006

PtFT1 expression pttFT1/18Sx10 LD SD Time (hours) Böhlenius et al., Science 2006

PtFT1 RNAi Induces Premature Bud Set Böhlenius et al., Science 2006

PtFT1 Controls Dual Aspects of Perennial Growth Behaviour Induction of reproductive phase Growth cessation and bud set 4 3 MAY JUNE 2 pttFT1/18Sx10 1 0 0 2 4 6 8 Time (years) Time (years) Time (years) Time (hours)

Seasonal Regulation of PtFT1 30 year old Populus tremula growing in Umeå (64°N) 21 hrs critical daylength?

Critical Daylength for Growth Cessation and Bud Set Umeå 63°N: 21 hrs Stockholm 59°N: 19 hrs Ronneby 56°N: 17 hrs Dresden 50°N: 15 hrs Provenances of European Aspen ( Populus tremula ) Böhlenius et al., Science 2006

At the Critical Daylength PtFT1 is Down-Regulated (21 hrs) (19 hrs) (17 hrs) (15 hrs) Böhlenius et al., Science 2006

Could the Phase of CO mRNA Oscillation be Setting the Critical Daylength? 16 hrs 12 hrs 8 hrs

The Phase of CO mRNA Oscillation Predicts the Critical Daylength (21 hrs) (19 hrs) (17 hrs) (15 hrs) Böhlenius et al. . 2006. Science 312, 1040-1043

Aspen Annuals and Perennials Arabidopsis

Tree secondary growth produces wood Tree secondary growth produces wood

Organization of the Vascular Meristem Organization of the Vascular Meristem Cambium Phloem mother cells Xylem mother cells Development Jeanette Nilsson

Expression in cells of provascular tissue Expression in cells of provascular tissue Pith Primary CambiumPrimary Phloem xylem Jeanette Nilsson

Pt t HB3 expression defines provascular development A & B C & D Jeanette Nilsson

Pt t HB3 RNAi affects secondary growth Pt t HB3 RNAi affects secondary growth Jeanette Nilsson

Reduced growth rate of xylem Reduced growth rate of xylem Jeanette Nilsson

Reduced activity in the cambium Reduced activity in the cambium T89 Phloem Cambium Xylem PttHB3 RNAi C Ph Xm Jeanette Nilsson

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”

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