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Research article - Peer-reviewed, 2012

Linking photoreceptor excitation to changes in plant architecture

Li, Lin; Ljung, Karin; Breton, Ghislain; Schmitz, Robert J.; Pruneda-Paz, Jose; Cowing-Zitron, Chris; Cole, Benjamin J.; Ivans, L; Pedmale, Ullas V.; Jung, Hou-Sung; Ecker, Joseph R.; Kay, Steve A.; Chory, Joanne

Abstract

Plants sense neighbor proximity as a decrease in the ratio of red to far-red light, which triggers a series of developmental responses. In Arabidopsis, phytochrome B (PHYB) is the major sensor of shade, but PHYB excitation has not been linked directly to a growth response. We show that the basic helix-loop-helix (bHLH) transcription factor PIF7 (phytochrome-interacting factor 7), an interactor of PHYB, accumulates in its dephosphorylated form in shade, allowing it to bind auxin biosynthetic genes and increase their expression. New auxin synthesized through a PIF7-regulated pathway is required for shade-induced growth, linking directly the perception of a light quality signal to a rapid growth response.

Keywords

auxin; phytochrome; shade avoidance

Published in

Genes and Development
2012, Volume: 26, number: 8, pages: 785-790
Publisher: COLD SPRING HARBOR LAB PRESS, PUBLICATIONS DEPT