Auxin and ethylene regulate elongation responses to neighbor proximity signals independent of gibberellin and della proteins in Arabidopsis.

Plants modify growth in response to the proximity of neighbors. Among these growth adjustments are shade avoidance responses, such as enhanced elongation of stems and petioles, that help plants to reach the light and outgrow their competitors. Neighbor detection occurs through photoreceptor-mediated detection of light spectral changes (i.

Struggling for light: della regulation during plant-plant interactions.

We recently described how DELLA proteins are involved in plant growth responses to neighbors in dense stands. These responses that are called shade avoidance include enhanced stem and petiole elongation and are a classic example of adaptive phenotypic plasticity. Although much is known about neighbor detection, much less is known about the signal transduction network downstream of these signals.

DELLA protein function in growth responses to canopy signals.

Plants can sense neighbour competitors through light-quality signals and respond with shade-avoidance responses. These include increased shoot elongation, which enhances light capture and thus competitive power. Such plant-plant interactions therefore profoundly affect plant development in crowded populations.