Hormonal regulation of root hair growth and responses to the environment in Arabidopsis.

Kris Vissenberg,Naomi Claeijs,Daria Balcerowicz,Sébastjen Schoenaers,Miriam Gifford

doi:10.1093/jxb/eraa048

Kris Vissenberg, Naomi Claeijs + Show 3 more

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https://doi.org/10.1093/jxb/eraa048

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Abstract

The main functions of plant roots are water and nutrient uptake, soil anchorage, and interaction with soil-living biota. Root hairs, single cell tubular extensions of root epidermal cells, facilitate or enhance these functions by drastically enlarging the absorptive surface. Root hair development is constantly adapted to changes in the root's surroundings, allowing for optimization of root functionality in heterogeneous soil environments. The underlying molecular pathway is the result of a complex interplay between position-dependent signalling and feedback loops. Phytohormone signalling interconnects this root hair signalling cascade with biotic and abiotic changes in the rhizosphere, enabling dynamic hormone-driven changes in root hair growth, density, length, and morphology. This review critically discusses the influence of the major plant hormones on root hair development, and how changes in rhizosphere properties impact on the latter.

Highlights

Roots provide structural anchorage and access to water and nutrients, which is vital to plant survival
Dynamic root hair morphogenesis is a key trait for improving the acquisition of essential nutrients in heterogeneous soils.a better understanding of the root hair developmental pathway is crucial.Various studies, mostly based on the model organism Arabidopsis, have led to a better understanding of the genetic and molecular cascade that lies at the base of root hair development (Balcerowicz et al, 2015; Schoenaers et al, 2017)
Plants are confronted with osmotic stress, causing cell dehydration and membrane/macromolecule damage (Lisar et al.,2012).Primary root growth,lateral root formation, and root hair development are reduced upon osmotic stress, a process that is heavily controlled by Abscisic acid (ABA) in a complex interacting network with cytokinin and other phytohormones (De Smet et al, 2003; Nakashima et al, 2014; Singh and Laxmi, 2015; Rowe et al, 2016;Tiwari et al, 2017).ABA stimulates the expression of the gene for ABSCISIC ACID INSENSITIVE4 (ABI4) transcription factor, among many other genes, which in turn inhibits PIN1 expression, leading to reduced polar auxin transport (Shkolnik-Inbar and Bar-Zvi, 2010) and lower auxin levels in the root

Summary

Introduction

Roots provide structural anchorage and access to water and nutrients, which is vital to plant survival. The gaseous hormone ethylene is a positive regulator of root hair development, and frequently found to functionally interact with auxin signalling (Dubois et al.,2018).

Results

Conclusion