A Solanum lycopersicum polyamine oxidase contributes to the control of plant growth, xylem differentiation, and drought stress tolerance.

Polyamines are involved in several plant physiological processes. In Arabidopsis thaliana, five FAD-dependent polyamine oxidases (AtPAO1 to AtPAO5) contribute to polyamine homeostasis. AtPAO5 catalyzes the back-conversion of thermospermine (T-Spm) to spermidine and plays a role in plant development, xylem differentiation, and abiotic stress tolerance.

Distinct role of AtCuAOβ- and RBOHD-driven HO production in wound-induced local and systemic leaf-to-leaf and root-to-leaf stomatal closure.

Polyamines (PAs) are ubiquitous low-molecular-weight aliphatic compounds present in all living organisms and essential for cell growth and differentiation. The developmentally regulated and stress-induced copper amine oxidases (CuAOs) oxidize PAs to aminoaldehydes producing hydrogen peroxide (HO) and ammonia. The CuAOβ (AtCuAOβ) was previously reported to be involved in stomatal closure and early root protoxylem differentiation induced by the wound-signal MeJA apoplastic HO production, suggesting a role of this enzyme in water balance, by modulating xylem-dependent water supply and stomata-dependent water loss under stress conditions.

A New Player in Jasmonate-Mediated Stomatal Closure: The Copper Amine Oxidase β.

Plant defence responses to adverse environmental conditions include different stress signalling, allowing plant acclimation and survival. Among these responses one of the most common, immediate, and effective is the modulation of the stomatal aperture, which integrates different transduction pathways involving hydrogen peroxide (HO), calcium (Ca), nitric oxide (NO), phytohormones and other signalling components. The () encodes an apoplastic CuAO expressed in guard cells and root protoxylem tissues which oxidizes polyamines to aminoaldehydes with the production of HO and ammonia.

Arabidopsis N-acetyltransferase activity 2 preferentially acetylates 1,3-diaminopropane and thialysine.

Polyamine acetylation has an important regulatory role in polyamine metabolism. It is catalysed by GCN5-related N-acetyltransferases, which transfer acetyl groups from acetyl-coenzyme A to the primary amino groups of spermidine, spermine (Spm), or other polyamines and diamines, as was shown for the human Spermidine/Spermine N-acetyltransferase 1 (HsSSAT1). SSAT homologues specific for thialysine, a cysteine-derived lysine analogue, were also identified (e.

Plant Copper Amine Oxidases: Key Players in Hormone Signaling Leading to Stress-Induced Phenotypic Plasticity.

Polyamines are ubiquitous, low-molecular-weight aliphatic compounds, present in living organisms and essential for cell growth and differentiation. Copper amine oxidases (CuAOs) oxidize polyamines to aminoaldehydes releasing ammonium and hydrogen peroxide, which participates in the complex network of reactive oxygen species acting as signaling molecules involved in responses to biotic and abiotic stresses. CuAOs have been identified and characterized in different plant species, but the most extensive study on a gene family has been carried out in .

Mutation of Arabidopsis Copper-Containing Amine Oxidase Gene Alters Polyamines, Reduces Gibberellin Content and Affects Development.

Polyamines (PAs) are essential metabolites in plants performing multiple functions during growth and development. Copper-containing amine oxidases (CuAOs) catalyse the catabolism of PAs and in are encoded by a gene family. Two mutants of one gene family member, , showed delayed seed germination, leaf emergence, and flowering time.

Leaf-Wounding Long-Distance Signaling Targets AtCuAOβ Leading to Root Phenotypic Plasticity.

The Arabidopsis gene (At4g14940) encodes an apoplastic copper amine oxidase (CuAO) highly expressed in guard cells of leaves and flowers and in root vascular tissues, especially in protoxylem and metaxylem precursors, where its expression is strongly induced by the wound signal methyl jasmonate (MeJA). The hydrogen peroxide (HO) derived by the AtCuAOβ-driven oxidation of the substrate putrescine (Put), mediates the MeJA-induced early root protoxylem differentiation. Considering that early root protoxylem maturation was also induced by both exogenous Put and leaf wounding through a signaling pathway involving HO, in the present study we investigated the role of in the leaf wounding-induced early protoxylem differentiation in combination with Put treatment.

Developmental, hormone- and stress-modulated expression profiles of four members of the Arabidopsis copper-amine oxidase gene family.

Copper-containing amine oxidases (CuAOs) catalyze polyamines (PAs) terminal oxidation producing ammonium, an aminoaldehyde and hydrogen peroxide (HO). Plant CuAOs are induced by stress-related hormones, methyl-jasmonate (MeJA), abscisic acid (ABA) and salicylic acid (SA). In the Arabidopsis genome, eight genes encoding CuAOs have been identified.

The Copper Amine Oxidase AtCuAOδ Participates in Abscisic Acid-Induced Stomatal Closure in Arabidopsis.

Plant copper amine oxidases (CuAOs) are involved in wound healing, defense against pathogens, methyl-jasmonate-induced protoxylem differentiation, and abscisic acid (ABA)-induced stomatal closure. In the present study, we investigated the role of the CuAOδ (AtCuAOδ; At4g12290) in the ABA-mediated stomatal closure by genetic and pharmacological approaches. Obtained data show that is up-regulated by ABA and that two T-DNA insertional mutants are less responsive to this hormone, showing reduced ABA-mediated stomatal closure and HO accumulation in guard cells as compared to the wild-type (WT) plants.

The Four FAD-Dependent Histone Demethylases of Arabidopsis Are Differently Involved in the Control of Flowering Time.

In , four FAD-dependent lysine-specific histone demethylases (LDL1, LDL2, LDL3, and FLD) are present, bearing both a SWIRM and an amine oxidase domain. In this study, a comparative analysis of gene structure, evolutionary relationships, tissue- and organ-specific expression patterns, physiological roles and target genes for the four Arabidopsis is reported. Phylogenetic analysis evidences a different evolutionary history for the four , while promoter activity data show that are strongly expressed during plant development and embryogenesis, with some gene-specific expression patterns.

Maize polyamine oxidase in the presence of spermine/spermidine induces the apoptosis of LoVo human colon adenocarcinoma cells.

Amine oxidases, which contribute to the regulation of polyamine levels, catalyze the oxidative deamination of polyamines to generate H2O2 and aldehyde(s). In this study, and at least to the best of our knowledge, maize polyamine oxidase (ZmPAO) was used for the first time with the aim of identifying a novel strategy for cancer therapy. The cytotoxicity and the mechanisms of cell death induced by the enzymatic oxidation products of polyamine generated by ZmPAO were investigated.

Stress-Triggered Long-Distance Communication Leads to Phenotypic Plasticity: The Case of the Early Root Protoxylem Maturation Induced by Leaf Wounding in Arabidopsis.

Root architecture and xylem phenotypic plasticity influence crop productivity by affecting water and nutrient uptake, especially under those environmental stress, which limit water supply or imply excessive water losses. Xylem maturation depends on coordinated events of cell wall lignification and developmental programmed cell death (PCD), which could both be triggered by developmental- and/or stress-driven hydrogen peroxide (H₂O₂) production. Here, the effect of wounding of the cotyledonary leaf on root protoxylem maturation was explored in by analysis under Laser Scanning Confocal Microscope (LSCM).

Determination of Copper Amine Oxidase Activity in Plant Tissues.

Copper amine oxidases (CuAOs) involved in polyamine catabolism are emerging as physiologically relevant enzymes for their involvement in plant growth, differentiation and defence responses to biotic and abiotic stress. In this chapter, we describe two spectrophotometric and one polarographic method for determining CuAO activity in plant tissues. Some aspects related to cell wall association of apoplastic CuAOs and possible interference of plant metabolites with the enzymatic activity assays are also considered.

The Arabidopsis polyamine oxidase/dehydrogenase 5 interferes with cytokinin and auxin signaling pathways to control xylem differentiation.

In plants, the polyamines putrescine, spermidine, spermine (Spm), and thermospermine (Therm-Spm) participate in several physiological processes. In particular, Therm-Spm is involved in the control of xylem differentiation, having an auxin antagonizing effect. Polyamine oxidases (PAOs) are FAD-dependent enzymes involved in polyamine catabolism.

Copper-Containing Amine Oxidases and FAD-Dependent Polyamine Oxidases Are Key Players in Plant Tissue Differentiation and Organ Development.

Plant polyamines are catabolized by two classes of amine oxidases, the copper amine oxidases (CuAOs) and the flavin adenine dinucleotide (FAD)-dependent polyamine oxidases (PAOs). These enzymes differ to each other in substrate specificity, catalytic mechanism and subcellular localization. CuAOs and PAOs contribute to several physiological processes both through the control of polyamine homeostasis and as sources of biologically-active reaction products.

POLYAMINE OXIDASE2 of Arabidopsis contributes to ABA mediated plant developmental processes.

Polyamines (PA) are catabolised by two groups of amine oxidases, the copper-binding amine oxidases (CuAOs) and the FAD-binding polyamine oxidases (PAOs). Previously, we have shown that CuAO1 is involved in ABA associated growth responses and ABA- and PA-mediated rapid nitric oxide (NO) production. Here we report the differential regulation of expression of POLYAMINE OXIDASE2 of Arabidopsis (AtPAO2) in interaction with ABA, nitrate and ammonium.

The MeJA-inducible copper amine oxidase AtAO1 is expressed in xylem tissue and guard cells.

Copper amine oxidases oxidize the polyamine putrescine to 4-aminobutanal with the production of the plant signal molecule hydrogen peroxide (H2O2) and ammonia. The Arabidopsis (Arabidopsis thaliana) gene At4g14940 (AtAO1, previously referred to as ATAO1) encodes an apoplastic copper amine oxidase expressed in lateral root cap cells and developing xylem, especially in root protoxylem and metaxylem precursors. In our recent study, we demonstrated that AtAO1 expression is strongly induced in the root vascular tissues by the wound-signal hormone methyl jasmonate (MeJA).

The Apoplastic Copper AMINE OXIDASE1 Mediates Jasmonic Acid-Induced Protoxylem Differentiation in Arabidopsis Roots.

Polyamines are involved in key developmental processes and stress responses. Copper amine oxidases oxidize the polyamine putrescine (Put), producing an aldehyde, ammonia, and hydrogen peroxide (H2O2). The Arabidopsis (Arabidopsis thaliana) amine oxidase gene At4g14940 (AtAO1) encodes an apoplastic copper amine oxidase expressed at the early stages of vascular tissue differentiation in roots.

Cell Wall Amine Oxidases: New Players in Root Xylem Differentiation under Stress Conditions.

Polyamines (PAs) are aliphatic polycations present in all living organisms. A growing body of evidence reveals their involvement as regulators in a variety of physiological and pathological events. They are oxidatively deaminated by amine oxidases (AOs), including copper amine oxidases (CuAOs) and flavin adenine dinucleotide (FAD)-dependent polyamine oxidases (PAOs).

Wound healing response and xylem differentiation in tobacco plants over-expressing a fungal endopolygalacturonase is mediated by copper amine oxidase activity.

In this work, we have investigated the involvement of copper amine oxidase (CuAO; EC 1.4.3.

Does polyamine catabolism influence root development and xylem differentiation under stress conditions?

Amine oxidases (AOs) oxidize polyamines (PAs) to aldehydes, simultaneously producing the removed amine moiety and hydrogen peroxide (H2O2). AOs, which include copper-containing amine oxidases (CuAOs) and flavin-containing amine oxidases (PAOs), are stress-inducible enzymes involved in both PA homeostasis and H2O2 production. Here, we suggest that H2O2 derived from PAO-mediated PA catabolism has a role in inducing root xylem differentiation during plant stress responses, whereas its involvement in this event during plant development under physiological conditions is not suitably supported by the currently available data.

Polyamine catabolism: target for antiproliferative therapies in animals and stress tolerance strategies in plants.

Metabolism of polyamines spermidine and spermine, and their diamine precursor, putrescine, has been a target for antineoplastic therapy since these naturally occurring alkyl amines were found essential for normal mammalian cell growth. Intracellular polyamine concentrations are maintained at a cell type-specific set point through the coordinated and highly regulated interplay between biosynthesis, transport, and catabolism. A correlation between regulation of cell proliferation and polyamine metabolism is described.

Perturbation of polyamine catabolism can strongly affect root development and xylem differentiation.

Spermidine (Spd) treatment inhibited root cell elongation, promoted deposition of phenolics in cell walls of rhizodermis, xylem elements, and vascular parenchyma, and resulted in a higher number of cells resting in G(1) and G(2) phases in the maize (Zea mays) primary root apex. Furthermore, Spd treatment induced nuclear condensation and DNA fragmentation as well as precocious differentiation and cell death in both early metaxylem and late metaxylem precursors. Treatment with either N-prenylagmatine, a selective inhibitor of polyamine oxidase (PAO) enzyme activity, or N,N(1)-dimethylthiourea, a hydrogen peroxide (H(2)O(2)) scavenger, reverted Spd-induced autofluorescence intensification, DNA fragmentation, inhibition of root cell elongation, as well as reduction of percentage of nuclei in S phase.

Plant amine oxidases "on the move": an update.

Amine oxidases (AOs) catalyse the oxidative de-amination of polyamines, ubiquitous polycationic compounds involved in important events of cell life. They include the copper-containing amine oxidases (CuAOs; EC 1.4.

Synthesis of new linear guanidines and macrocyclic amidinourea derivatives endowed with high antifungal activity against Candida spp. and Aspergillus spp.

New linear and cyclic guanidines were synthesized and tested in vitro for their antifungal activity toward clinically relevant strains of Candida species, in comparison to fluconazole. Macrocyclic compounds showed a minimum inhibitory concentration in the micromolar range and a biological activity profile in some cases better than that of fluconazole. One macrocyclic derivative was also tested against Aspergillus species and showed high antifungal activity comparable to that of amphotericin B and itraconazole.