Editors' ChoicePlant biology

One Hormone, Two Phases

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Sci. Signal.  13 May 2014:
Vol. 7, Issue 325, pp. ec127
DOI: 10.1126/scisignal.2005464

The switch from vegetative growth to flowering in the plant Arabidopsis involves two phases—inflorescence branching and flowering. Yamaguchi et al. examined how the phytohormone gibberellin regulates each phase differently. First, gibberellin levels increase and stimulate production of key flowering factors, one of which degrades gibberellin. As gibberellin levels then fall, the next phase of flowering factors is released from gibberellin repression. By regulating inflorescence branching separately from flowering, this system determines overall seed yield.

N. Yamaguchi, C. M. Winter, M.-F. Wu, Y. Kanno, A. Yamaguchi, M. Seo, D. Wagner, Gibberellin acts positively then negatively to control onset of flower formation in Arabidopsis. Science 344, 638–641 (2014). [Abstract] [Full Text]