Root hair growth: it's a one way street

Abstract

Over the last few decades, our understanding of directed cell growth in different organisms has substantially improved. Tip-growing cells in plants elongate rapidly via targeted deposition of cell wall and membrane material at the cell apex, and use turgor pressure as a driving force for expansion. This type of polar growth requires a high degree of coordination between a plethora of cellular and extracellular components and compounds, including calcium dynamics, apoplastic reactive oxygen species and pH, the cytoskeleton, and vesicular trafficking. In this review, we attempt to outline and summarize the factors that control root hair growth and how they work together as a team.

Improving Plant Water Use Efficiency through Molecular Genetics

“…The combination of long root hairs and shallow basal roots results in a synergistic effect on phosphorus acquisition that translates to a 300% increase in biomass in cultivars with both traits [42]. Several components of the molecular mechanisms that control root hair growth have been elucidated [43]. Modifying the expression of some of the genes that control root hair development has resulted in plants with longer and highly branched root hairs [44,45].…”

Signaling with Ions: The Keystone for Apical Cell Growth and Morphogenesis in Pollen Tubes

“…In addition, root hair length is controlled through a signaling network involving ROOTHAIR DEFECTIVE SIX-LIKE (RSL) transcription factors (Honkanen and Dolan, 2016). In spite of those main differences, the apical growth of root hairs and PTs is characterized by apical exocytosis of new cell wall material, similar ion gradients, fluxes at the tip, and a mechanism depending on actin cytoskeleton supporting cell elongation (Gu and Nielsen, 2013;Ketelaar, 2013;Mendrinna and Persson, 2015;Mangano et al, 2016).…”

Interplay between Ions, the Cytoskeleton, and Cell Wall Properties during Tip Growth

“…Ultimately, the key to understanding tip growth will require understanding a complex interaction network; the reader is directed to recent reviews that expand upon a variety of facets of tip growth not covered here (Mendrinna and Persson, 2015;Hepler, 2016;Damineli et al, 2017;Michard et al, 2017;Stephan, 2017). In this Update, we speculate that further mechanistic advances will come from identifying deeply conserved tip growth mechanisms that decipher signaling events between the cell wall and the cytoplasm.…”