ROS Regulation of Polar Growth in Plant Cells

Abstract

ORCID ID: 0000-0001-6332-7738 (J.M.E.).Root hair cells and pollen tubes, like fungal hyphae, possess a typical tip or polar cell expansion with growth limited to the apical dome. Cell expansion needs to be carefully regulated to produce a correct shape and size. Polar cell growth is sustained by oscillatory feedback loops comprising three main components that together play an important role regulating this process. One of the main components are reactive oxygen species (ROS) that, together with calcium ions (Ca 2+ ) and pH, sustain polar growth over time. Apoplastic ROS homeostasis controlled by NADPH oxidases as well as by secreted type III peroxidases has a great impact on cell wall properties during cell expansion. Polar growth needs to balance a focused secretion of new materials in an extending but still rigid cell wall in order to contain turgor pressure. In this review, we discuss the gaps in our understanding of how ROS impact on the oscillatory Ca 2+ and pH signatures that, coordinately, allow root hair cells and pollen tubes to expand in a controlled manner to several hundred times their original size toward specific signals.

Thioredoxin-Mediated ROS Homeostasis Explains Natural Variation in Plant Regeneration

“…High levels of ROS result in reduced 92 root meristem activity (Tsukagoshi et al, 2010), and small leaf size . ROS is also 93 involved in regulating polar growth of pollen and root hairs (Mangano et al, 2016), and senescence 94 of leaf and flower (Rogers and Munné-Bosch, 2016). In addition, ROS is generated in various 95 subcellular compartments.…”

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

“…Reactive oxygen species (ROS) also have been long implicated in ion dynamics regulation in PTs. The subject has been reviewed elsewhere (Wudick and Feijó, 2014;Mangano et al, 2016), so it will only be alluded to briefly here. Tip-localized ROS in growing PTs have been described in Arabidopsis (Potocky et al, 2007), and double mutants of the pollen-expressed H and J members of respiratory burst oxidase homolog (Rboh) have PT phenotypes and altered Ca 2+ gradient features Boisson-Dernier et al, 2013;Kaya et al, 2014Kaya et al, , 2015Lassig et al, 2014).…”

“…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).…”

Recent Progress in Understanding the Role of Reactive Oxygen Species in Plant Cell Signaling

“…Our most detailed knowledge of ROS functions still comes from work with photosynthesizing leaves; therefore, the majority of reports in this special issue focus on leaf processes. Other contributions address ROS-dependent regulation of flower senescence (Rogers and Munné-Bosch, 2016), polar growth of pollen and root hairs (Mangano et al, 2016), and other root processes, including root architecture formation (Evans et al, 2016;Liu et al, 2016).…”