Polyamines and abiotic stress in plants: a complex relationship1

Abstract

The physiological relationship between abiotic stress in plants and polyamines was reported more than 40 years ago. Ever since there has been a debate as to whether increased polyamines protect plants against abiotic stress (e.g., due to their ability to deal with oxidative radicals) or cause damage to them (perhaps due to hydrogen peroxide produced by their catabolism). The observation that cellular polyamines are typically elevated in plants under both short-term as well as long-term abiotic stress conditions is consistent with the possibility of their dual effects, i.e., being protectors from as well as perpetrators of stress damage to the cells. The observed increase in tolerance of plants to abiotic stress when their cellular contents are elevated by either exogenous treatment with polyamines or through genetic engineering with genes encoding polyamine biosynthetic enzymes is indicative of a protective role for them. However, through their catabolic production of hydrogen peroxide and acrolein, both strong oxidizers, they can potentially be the cause of cellular harm during stress. In fact, somewhat enigmatic but strong positive relationship between abiotic stress and foliar polyamines has been proposed as a potential biochemical marker of persistent environmental stress in forest trees in which phenotypic symptoms of stress are not yet visible. Such markers may help forewarn forest managers to undertake amelioration strategies before the appearance of visual symptoms of stress and damage at which stage it is often too late for implementing strategies for stress remediation and reversal of damage. This review provides a comprehensive and critical evaluation of the published literature on interactions between abiotic stress and polyamines in plants, and examines the experimental strategies used to understand the functional significance of this relationship with the aim of improving plant productivity, especially under conditions of abiotic stress.

Phloem-Specific Methionine Recycling Fuels Polyamine Biosynthesis in a Sulfur-Dependent Manner and Promotes Flower and Seed Development

“…Among many other roles, PAs can function as compatible solutes, protective substances for nucleotides and membranes, as scavengers for reactive oxygen species, and as promoters for the production of antioxidant enzymes and metabolites (Minocha et al, 2014). Several reports also demonstrated the importance of spermine, particularly during long-term stress treatments.…”

“…In Arabidopsis, the main polyamines are putrescine, spermidine, spermine, and thermospermine. All polyamines have the ability to bind DNA but also contribute to plant tolerance to biotic and abiotic stresses (Jimènez-Bremont et al, 2014;Minocha et al, 2014). Spermine synthase (SPMS) has been shown to protect plants during salt stress.…”

Speculation: Polyamines are important in abiotic stress signaling

“…3). Abscisic acid-responsive elements (ABRE) or ABRE-related motifs occur in the promoters of ADC2, SPDS1 and SPMS, which are also highly up-regulated in Page 15 of 33 A c c e p t e d M a n u s c r i p t 15 response to drought stress [10]. Abscisic acid also influences the catabolism of polyamines as it induces the expression of PAO [59], while at the same time, polyamines influence abscisic acid synthesis [30].…”

“…Several reviews [6,[9][10] have dealt with the relationship between tolerance and the capacity to enhance the synthesis of polyamines upon exposure to stress. Plants overexpressing genes encoding enzymes involved in polyamine biosynthesis accumulate higher levels of polyamines and show enhanced tolerance to various stresses [9][10][11][12][13][14].…”

“…Plants overexpressing genes encoding enzymes involved in polyamine biosynthesis accumulate higher levels of polyamines and show enhanced tolerance to various stresses [9][10][11][12][13][14]. This suggests that an increase in polyamine synthesis is effective against all types of stress.…”