The Interplay among Polyamines and Nitrogen in Plant Stress Responses

Abstract

The interplay between polyamines (PAs) and nitrogen (N) is emerging as a key factor in plant response to abiotic and biotic stresses. The PA/N interplay in plants connects N metabolism, carbon (C) fixation, and secondary metabolism pathways. Glutamate, a pivotal N-containing molecule, is responsible for the biosynthesis of proline (Pro), arginine (Arg) and ornithine (Orn) and constitutes a main common pathway for PAs and C/N assimilation/incorporation implicated in various stresses. PAs and their derivatives are important signaling molecules, as they act largely by protecting and preserving the function/structure of cells in response to stresses. Use of different research approaches, such as generation of transgenic plants with modified intracellular N and PA homeostasis, has helped to elucidate a plethora of PA roles, underpinning their function as a major player in plant stress responses. In this context, a range of transgenic plants over-or under-expressing N/PA metabolic genes has been developed in an effort to decipher their implication in stress signaling. The current review describes how N and PAs regulate plant growth and facilitate crop acclimatization to adverse environments in an attempt to further elucidate the N-PAs interplay against abiotic and biotic stresses, as well as the mechanisms controlling N-PA genes/enzymes and metabolites.

Abiotic Stress Responses in Plants: Current Knowledge and Future Prospects

“…Exogenous application of polyamine and/or inhibitors of enzymes which are involved in polyamine biosynthesis also hints towards a possible role of such compounds in plant adaptation or defense process in response to environmental stresses [76]. Moreover, studies involving either transgenic overexpression or loss of function mutants support the protective, adaptive, or defensive role of polyamines in plant's response to various abiotic stresses [76,77].…”

The Role of Proteases in Determining Stomatal Development and Tuning Pore Aperture: A Review

“…While ABA appears to be a key regulator in stomatal closure, both salicylic acid (SA) and hydrogen peroxide, which are produced under several modes following pathogen attack and stress stimuli, are also involved. Indeed, SA and hydrogen peroxide have been both shown to halt pathogen penetration inside the plant body [59][60][61]. Recently, Ziemann et al [62] reported that through the activity of a Papain-like cysteine protease, the immune signaling peptide 1 (ZIP1) is matured from its pro-peptide, and serves as an activator of SA signaling via transcriptional upregulation.…”

Halotropism: Phytohormonal Aspects and Potential Applications

“…Emerging interest has been added to study PAs in halophytes in salt tolerance ( Bueno and Cordovilla, 2019 ), emphasizing the regulatory role of polyamines in abiotic stress as hub molecules ( Sequera-Mutiozabal et al., 2017 ). Cooperating with other plant hormones such as cytokinin ( Černý et al., 2013 ) and interacting with nitrogen in stress responses make them able to fine tune the proper C/N ratio in order to achieve the optimal conditions for growth or stress responses ( Paschalidis et al., 2019 ). Moreover, PAs reprogramming oxidative and nitrosative status of salt exposed citrus plants could affect their redox status ( Tanou et al., 2014 ).…”