Modulation of plant growth by day length dependent regulation of the TOR signaling pathway

Thumbnail Image
Hamilton, Ferga
Journal Title
Journal ISSN
Volume Title
University College Cork
Published Version
Research Projects
Organizational Units
Journal Issue
Plant growth occurs through cell growth and proliferation, which are high energy demanding processes. Plants need to coordinate growth responses with their environmental conditions to ensure the best use of their resources. This accurate regulation depends on the circadian clock, an internal time keeping mechanism that informs the plant of day length duration (photoperiod). The TOR (Target of Rapamycin) kinase pathway is a central hub where cellular energy levels are perceived and translated into specific growth responses across kingdoms. In plants, the TOR pathway has been associated with rapid growing tissue including embryos, shoot and root meristems. Downstream of TOR, the 40S ribosomal protein S6 Kinase 1 (S6K1) modulates both cell growth and proliferation. Since S6K1 accumulation is modulated by the circadian clock, this thesis investigated how changes in S6K1 levels would affect plant growth when the clock function is impaired by mutation in ZTL (ZEITLUPE) which encodes a F-box protein that targets for degradation several components of the Arabidopsis clock. The findings show that de-regulation of TOR signaling pathway components impacts plant growth and development. This negative effect is reinforced by a defective circadian function, suggesting that plants require a running clock to match the TOR pathway activity with specific environmental conditions.
Circadian clock , TOR pathway , S6 kinase
Hamilton, F. 2022. Modulation of plant growth by day length dependent regulation of the TOR signaling pathway. MRes Thesis, University College Cork.