Paper of the Month July

Neighbor detection at the leaf tip adaptively regulates upward leaf movement through spatial auxin dynamics


Vegetation stands have a heterogeneous distribution of light quality,
including the red/far-red light ratio (R/FR) that informs plants about
proximity of neighbors. Adequate responses to changes in R/FR are
important for competitive success. How the detection and response to
R/FR are spatially linked and how this spatial coordination between
detection and response affects plant performance remains unresolved.
We show in Arabidopsis thaliana and Brassica nigra that localized FR
enrichment at the lamina tip induces upward leaf movement (hyponasty)
from the petiole base. Using a combination of organ-level transcriptome
analysis, molecular reporters, and physiology, we show that
PIF-dependent spatial auxin dynamics are key to this remote response
to localized FR enrichment. Using computational 3D modeling, we
show that remote signaling of R/FR for hyponasty has an adaptive
advantage over local signaling in the petiole, because it optimizes the
timing of leaf movement in response to neighbors and prevents hyponasty caused by self-shading.

Chrysoula K. Pantazopoulou, Franca J. Bongers, Jesse J. K├╝pers, Emilie Reinen, Debatosh Das, Jochem B. Evers, Niels P. R. Anten, and Ronald Pierik (2017) PNAS (online first)

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