Strategies of seedlings to overcome their sessile nature: Auxin in mobility control Journal Article

Author(s): Žádníková, Petra; Smet, Dajo; Zhu, Qiang; Van Der Straeten, Dominique; Benková, Eva
Article Title: Strategies of seedlings to overcome their sessile nature: Auxin in mobility control
Affiliation IST Austria
Abstract: Plants are sessile organisms that are permanently restricted to their site of germination. To compensate for their lack of mobility, plants evolved unique mechanisms enabling them to rapidly react to ever changing environmental conditions and flexibly adapt their postembryonic developmental program. A prominent demonstration of this developmental plasticity is their ability to bend organs in order to reach the position most optimal for growth and utilization of light, nutrients, and other resources. Shortly after germination, dicotyledonous seedlings form a bended structure, the so-called apical hook, to protect the delicate shoot meristem and cotyledons from damage when penetrating through the soil. Upon perception of a light stimulus, the apical hook rapidly opens and the photomorphogenic developmental program is activated. After germination, plant organs are able to align their growth with the light source and adopt the most favorable orientation through bending, in a process named phototropism. On the other hand, when roots and shoots are diverted from their upright orientation, they immediately detect a change in the gravity vector and bend to maintain a vertical growth direction. Noteworthy, despite the diversity of external stimuli perceived by different plant organs, all plant tropic movements share a common mechanistic basis: differential cell growth. In our review, we will discuss the molecular principles underlying various tropic responses with the focus on mechanisms mediating the perception of external signals, transduction cascades and downstream responses that regulate differential cell growth and consequently, organ bending. In particular, we highlight common and specific features of regulatory pathways in control of the bending of organs and a role for the plant hormone auxin as a key regulatory component.
Keywords: Gravitropism; Auxin; Hormonal crosstalk; Apical hook; Phototropism; Differential growth
Journal Title: Frontiers in Plant Science
Volume: 6
Issue 4
ISSN: 1664-462X
Publisher: Frontiers Research Foundation  
Date Published: 2015-04-14
Start Page: Article number: 218
Copyright Statement: CC BY
DOI: 10.3389/fpls.2015.00218
Notes: This work was supported by the European Research Council with a Starting Independent Research grant (ERC-2007- Stg-207362-HCPO) and the and the Grant Agency of the Czech Republic (GACR, GA13-39982S) to EB, and by research grants from the Research Foundation Flanders (G.0656.13N) and Ghent University to DS. DS holds a PhD fellowship from the Research Foundation Flanders.
Open access: yes (OA journal)