Polyamines control of cation transport across plant membranes: implications for ion homeostasis and abiotic stress signaling

Abstract

Polyamines are unique polycationic metabolites, controlling a variety of vital functions in plants, including growth and stress responses. Over the last two decades a bulk of data was accumulated providing explicit evidence that polyamines play an essential role in regulating plant membrane transport. The most straightforward example is a blockage of the two major vacuolar cation channels, namely slow (SV) and fast (FV) activating ones, by the micromolar concentrations of polyamines. This effect is direct and fully reversible, with a potency descending in a sequence Spm4+ > Spd3+ > Put2+. On the contrary, effects of polyamines on the plasma membrane (PM) cation and K+-selective channels are hardly dependent on polyamine species, display a relatively low affinity, and are likely to be indirect. Polyamines also affect vacuolar and PM H+ pumps and Ca2+ pump of the PM. On the other hand, catabolization of polyamines generates H2O2 and other reactive oxygen species (ROS), including hydroxyl radicals. Export of polyamines to the apoplast and their oxidation there by available amine oxidases results in the induction of a novel ion conductance and confers Ca2+ influx across the PM. This mechanism, initially established for plant responses to pathogen attack (including a hypersensitive response), has been recently shown to mediate plant responses to a variety of abiotic stresses. In this review we summarize the effects of polyamines and their catabolites on cation transport in plants and discuss the implications of these effects for ion homeostasis, signaling, and plant adaptive responses to environment.

Osmotic stress affects polyamine homeostasis and phenolic content in proembryogenic liquid cell cultures of Scots pine

“…Transgenic tobacco plants with decreased PAO activity and increased Spd and Spm titers were more tolerant to salinity stress than genotypes with increased PAO activity (Moschou et al 2008b). PAs have been shown to modulate the activity of a certain set of ion channels to adapt ionic fluxes in response to environmental changes (Pottosin and Shabala 2014). Spm with three positive charges in its molecule has been viewed as the most effective PA in regulating ion channels (Yamaguchi et al 2007).…”

Polyamines are common players in different facets of plant programmed cell death

“…Polyamines also regulate ion channels such as those involved in K + efflux and Ca 2+ influx during the progression of hypersensitive response, which are relevant for the activation of metacaspases and for ROS production (Watanabe and Lam 2011). The formation of hydrogen peroxide and cytotoxic products via PA catabolism is considered to be one of the possible mechanisms of PA involvement in PCD (Yoda et al 2006), and the ability of plants to control stress is related to their capacity to metabolise PAs (Alcázar et al 2010;Pottosin and Shabala 2014).…”

Deregulation of apoplastic polyamine oxidase affects development and salt response of tobacco plants

“…Externally applied PAs inhibit in roots the voltageindependent non-selective cation current (VI-NSCC), which is almost equally permeable to K + and Na + , as well as to divalent cations (Ca 2+ ). Export and oxidation of PAs in the apoplast by PAO results in the induction of a novel ion conductance and confers Ca 2+ influx across the plasma membrane, whereas PAs and ion channels cross-talk through the PAO-generated ROS (Pottosin, 2015;Pottosin and Shabala, 2014 and references therein).…”