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Regulation of flowering time and phenology in Populus trees

Marcon, Alice

Sammanfattning

As sessile organisms, plants must adapt to a variety of environmental conditions. Perennials in particular, face prolonged exposure to both abiotic and biotic stresses. The growth of perennial plants such as poplar trees (Populus spp.) is dictated by the change of seasons. At northern latitudes, the growth cycle of trees alternates between a period of active growth and dormancy, during which the trees are unreceptive to any growth promoting signals to ensure that buds do not flush before winter has passed. Previous studies of the phenology regulation in Populus have revealed interesting parallels to the photoperiodic flowering pathway in Arabidopsis thaliana.

In my work, I have investigated the role of FLOWERING LOCUS T (FT) and TERMINAL FLOWER 1 (TFL1)-like genes, which in arabidopsis induce and repress flowering respectively, in the control of flowering time and phenology in the annual growth cycle of Populus trees. Three FT-like genes have been identified and have evolved to take different functions. The data show that FT1 is involved in dormancy release while both FT2a and FT2b are crucial for vegetative growth during summer. Acting antagonistically to the FT genes, in a conserved mechanism to arabidopsis, two TFL1-like paralogues have been described. CENL1 and CENL2 in Populus are repressors of growth, although CENL2 seems to play only a minor role. CENL1 is involved in the maintenance of meristem indeterminacy and represses flowering, while FT1 can induce the transition to flowering after a period of dormancy.

Furthermore, I have provided a complete transcriptional atlas of the annual growth cycle of aspen, based on RNA sequencing of samples collected from outdoor and indoor grown trees mimicking seasonal changes. This allowed me to investigate the molecular responses which regulate essential developmental processes during the growth cycle in trees.

Nyckelord

Populus; flowering; growth cycle; transcriptome; FLOWERING LOCUS T; TERMINAL FLOWER 1

Publicerad i

Acta Universitatis Agriculturae Sueciae
2025, nummer: 2025:11
Utgivare: Swedish University of Agricultural Sciences

SLU författare

UKÄ forskningsämne

Botanik
Skogsvetenskap

Publikationens identifierare

  • DOI: https://doi.org/10.54612/a.3e1a1pjirr
  • ISBN: 978-91-8046-446-8
  • eISBN: 978-91-8046-496-3

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/132951