Shoot branching – role of strigolactones and interactions with other signals

Beveridge C1, Chabikwa T1, Kerr S1, Han F1, Fichtner F2, Lunn J2 and Barbier F1

  1. The University of Queensland, School of Biological Sciences, Brisbane, Australia.
  2. Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1.

Shoot branching occurs due to the regulation of the outgrowth of axillary buds which are embryonic shoots in the axil of leaves. Long-distance signaling is central to this regulation and mainly involves strigolactones, cytokinins, auxin and sugars. The sugar role may be at least partly due to sugar signalling and to involve trehalose 6-phosphate. It also appears that the growth of axillary buds from a state of very slow growth or dormancy, to sustained growth involves a number of stages during which the emerging shoots show differential sensitivity to growth stimulus and inhibition. For example, there are substantial differences in responses to different hormones at different periods after shoot tip removal. This could be due to differences in hormone signaling and downstream responses as well as due to changes in the vasculature of the growing buds. We will present our latest unpublished findings on the interaction of signals during bud outgrowth. In addition to providing a new mechanism for how plants respond to shoot tip removal, this work is provides a better understanding of how plants achieve diverse architecture in response to the environment.