Polyamine Treatment Research Articles

The effect of spermidine supplementation on polyamine metabolism and Fusarium infection in Linum usitatissimum

Flax (Linum usitatissimum) is a valuable industrial crop in temperate climate zones. However, the prevalence of fungal diseases, particularly those caused by Fusarium oxysporum sp. linii, poses a substantial threat, leading to significant crop losses and diminished interest in flax cultivation. In this study, flax plants were treated with spermidine and subsequently infected with Fusarium oxysporum to investigate multiple aspects: (1) the uptake of exogenous spermidine by the plants, (2) the impact of this uptake on the levels of other polyamines and the expression of polyamine biosynthesis genes, and (3) the effects of fungal infection on these parameters. The results demonstrated that flax plants effectively absorb spermidine, leading to substantial changes in the levels of polyamines and the expression of related genes in both roots and shoots. Notably, spermidine treatment resulted in significant alterations in the levels of putrescine and spermine, as well as in the transcript levels of key genes involved in polyamine biosynthesis. Moreover, Fusarium oxysporum infection itself induced changes in polyamine content and gene expression, which varied between root and shoot tissues. When spermidine-treated plants were infected with Fusarium oxysporum, a more complex response was observed, characterized by modifications in polyamine levels and gene expression that suggest an enhanced defense mechanism against the pathogen. These findings indicate that polyamine treatment not only affects the infection process but also modulates the plant's internal polyamine metabolism and gene expression, contributing to an improved resistance to fungal attack. This study highlights the potential of spermidine as a protective agent in flax and provides a foundation for further exploration of polyamine-related defense mechanisms.

How can biochar and polyamine treatments mitigate salt toxicity by changing the physiological traits in garlic plants?

How can biochar and polyamine treatments mitigate salt toxicity by changing the physiological traits in garlic plants?

Effects of Putrescine and Spermine on Pollen Germination Levels of Some Olive Cultivars

In this study, it is aimed to determine the effects of putrescine and spermine on pollen germination levels of 8 olive cultivars. Arbequina, Gemlik, Halhalı, Karamani, Kozan yerli, Saurani, Sayfi and Şami olive cultivars were used as material. In the study, 5 spermine doses (0,25mM, 0,125 mM, 0,025 mM, 0,05 mM and 0,005 mM) and 5 putrescine doses (0,20 mM, 0,10 mM, 0,05 mM, 0,025 mM and 0,1 mM) added to basal germination medium (15% sucrose + 1% agar + 100 ppm Boric acid) were tested for determining the effects on pollen germination of olive cultivars. Basal media was used for Control treatment. In terms of pollen germination media, pollen germination levels were increased with lower putrescine and higher spermine levels. In Sayfi olive cultivar, while pollen viability rate was 42,74%, pollen germination was 0,00% in control treatments. However, pollen germination was increased for Sayfi olive cultivar with 0,20 mM and 0,10 mM putrescine (3,64% and 3,40%, respectively) and 0,25 mM, 0,125 mM and 0,05 mM Spermine (12,56%, 4,73% and 3,40%, respectively). In conclusion, polyamine treatments were increased the low germinated cultivars. So, polyamine treatments reveal the potential of the pollen especially in low-germinated pollens.

Osa-miR11117 Targets OsPAO4 to Regulate Rice Immunity against the Blast Fungus Magnaporthe oryzae.

The intricate regulatory process governing rice immunity against the blast fungus Magnaporthe oryzae remains a central focus in plant-pathogen interactions. In this study, we investigated the important role of Osa-miR11117, an intergenic microRNA, in regulating rice defense mechanisms. Stem-loop qRT-PCR analysis showed that Osa-miR11117 is responsive to M. oryzae infection, and overexpression of Osa-miR11117 compromises blast resistance. Green fluorescent protein (GFP)-based reporter assay indicated OsPAO4 is one direct target of Osa-miR11117. Furthermore, qRT-PCR analysis showed that OsPAO4 reacts to M. oryzae infection and polyamine (PA) treatment. In addition, OsPAO4 regulates rice resistance to M. oryzae through the regulation of PA accumulation and the expression of the ethylene (ETH) signaling genes. Taken together, these results suggest that Osa-miR11117 is targeting OsPAO4 to regulate blast resistance by adjusting PA metabolism and ETH signaling pathways.

Genome-Wide Analysis of the AP2/ERF Family in Oily Persimmon (Diospyros oleifera) and Their Preliminary Roles Exploration in Response to Polyamines for Adventitious Root Formation in Cultivated Persimmon (D. kaki)

The AP2/ERF (APETALA2/Ethylene−Responsive element binding factor) family genes play crucial roles in plant growth and development, and responses to environmental factors; however, this family has not been characterized in Diospyros species. In Diospyros, the diploid Oily persimmon (D. oleifera, 2n = 2x = 30) has been released with complete genome assembly, which makes it possible for genome-wide gene family identification and exploration of molecular function in cultivated persimmon (D. kaki, 2n = 6x = 90). Here, we identified the AP2/ERF family in Oily persimmon for the first time and investigated its classification, main physicochemical properties, structural characteristic, chromosome distribution, gene replication and collinearity, cis-factor binding sites deduction, GO term annotation, and PPI interaction, as well as its expression profiles in different tissue and under the treatment of polyamines. A total of 157 AP2/ERF genes, including four subfamilies (AP2, RAV, Soloist, and ERF), were identified with distribution on all 15 chromosomes. DkAP2/ERF gene expression patterns were extensive and diverse. They were detected expression in every examined tissue, with the highest number of DkAP2/ERF genes expressed in the root. DkAP2/ERF gene expression analysis in adventitious root generation and elongation of polyamines showed their different responses to the action of polyamines, and more pairs of DkAP2/ERF genes with high correlation in gene expression were obtained. In addition, some DkAP2/ERF genes were detected remarkably correlated with genes related to polyamine synthesis and cell metabolism, including S-adenosyl-L-methionine Decarboxyla2 (SAMDC2), D-type cyclin1 (CYCD1), and D-type cyclin2 (CYCD2) genes,. indicating that DkAP2/ERF genes may play a synergistic role in adventitious root development This study was the first to analyze the AP2/ERF gene comprehensively in Diospyros on a genome−wide scale and will provide insights into the application of adventitious root formation in cultivated persimmon.

Effect of exogenous polyamines on coconut (<em>Cocos nucifera</em> L.) embryogenic callus multiplication

Major bottlenecks of coconut in vitro culture are poor plant regeneration rate, severe browning and premature necrosis of cultured tissue, and heterogeneous response of individual palms and explants to in vitro culture conditions. Among them, tissue browning is a common and often severe problem in coconut in vitro culture systems which results in death of explant/ callus ultimately. This experiment was carried out to enhance the in vitro multiplication of coconut, which is a highly recalcitrant species to in vitro culture through exogenously added polyamines in the media. The polyamines are important for in vitro cell division, cell growth and to delay senescence. In the present study, unfertilized ovary derived calli were cultured on Y3 basal medium supplemented with sucrose (5%), 2,4-D, phytagel (3 gL-1), activated charcoal (2.5 gL-1), and polyamine. Three polyamine types (O.lmM spermine, 1.0 mM putrescine and 0.5mM spermidine) were tested in combination with two 2,4-D concentrations (0.30 and 0.60 mM) in order to enhance coconut in vitro multiplication. All the cultures were incubated in dark at 26±2 °C. The embryogenic structures, embryogenic callusing, non-embryogenic callusing, and browning were recorded separately for each treatment after five weeks from the culture establishment. The polyamine treatments did not have significant effects on frequencies of embryogenic structures, embryogenic callus, non-embryogenic callus and browned callus formation at the initial stages of coconut somatic embryogenesis irrespective of the tested 2,4-D concentrations. Furthermore, the results indicated that decreased 2,4-D levels have significantly reduced browning, resulting 44.79 % browning frequency (0.8-fold lesser browning) in media supplemented with 0.30 mM 2,4-D. However, the potential effects of exogenously added polyamines at the initial stages of coconut somatic embryogenesis could be delivered during the latter stages of the somatic embryo genesis as previously reported in other experiments. Thus, continuous subculture may be necessary.

Genome-wide evolutionary analysis of AUX/IAA gene family in wheat identifies a novel gene TaIAA15-1A regulating flowering time by interacting with ARF

Flowering time is a critical agronomic trait that has strong effects on crop yields. Auxin signaling pathway plays an important role in various development processes, such as flowering, grain development. However, no Aux/IAA gene had been reported to have functions involving in wheat flowering time. Here, we systematically performed genome-wide identification, classification, domain distribution, exon-intron structure, chromosome locations and global expression pattern of Aux/IAA gene family in 14 plant genomes (including Triticum aestivum). A phylogenetic model was proposed to infer the Aux/IAA evolutionary history involving in a central exon-intron structure “2121” during evolution. Overexpression of TaIAA15-1A caused an early flowering time in Brachypodium. RNA-seq analysis showed that TaIAA15-1A overexpression alters various pathways including phytohormone signaling pathway, flowering-related pathway, and polyamine biosynthesis pathway. Screening of auxin response factor (ARF) genes identified BdARF16 that interacted with TaIAA15-1A. Exogenous polyamine (spermidine and spermine) treatments promoted early flowering and (putrescine and DCHA) delayed flowering time of WT plants. Our finding will provide insights on mechanisms of Aux/IAAs gene family and TaIAA15-1A, illustrating the potential during crop improvement programs.

Synergistic effect of polyamine treatment and chitosan coating on postharvest senescence and enzyme activity of bell pepper (Capsicum annuum L.) fruit

• Combination treatment of spermidine (SPD), spermine (SPM) and chitosan (Ch) as coating for extending shelf life of capsicum fruit. • Fruits were treated with coating solutions SPD and SPM @ 0.5, 1.0 and 1.5 mM, then coated with chitosan and stored at 10 ± 1 °C. • The biochemical parameters, enzymatic activities, antioxidant capacity and quality parameters were assessed in capsicum fruit during storage. • Spermine (1.5 mM) and chitosan 1% treatment showed the lowest weight loss and was adjudged best treatment to extend storability of capsicum fruit cv. “Rehana”. This study investigated the effects of treating bell pepper fruit cv. Rehana by dipping with spermidine and spermine (0.5, 1.0 and 1.5 mM) and coating with chitosan (1%) on fruit quality, bio-active compounds, antioxidant enzyme activities, shelf life and senescence related compounds. The fruit were stored at 10 °C and 80–90% RH for 56 days. The results revealed that synergistic treatment of spermine 1.5 mM and chitosan 1% (T7) was most effective for reducing weight loss, electrolyte leakage, maintaining fruit quality and enhancing antioxidant activity over other treatments during storage. The bell pepper fruit of T7 treatment exhibited lowered weight loss by 47.6%, electrolyte leakage by 62.6%, malondialdehyde accumulation by 28.3% while maintaining higher total phenols by 68.8%, total carotenoid by 21.9%, ascorbic acid by 15%, total chlorophyll by 30.4%, catalase activity by 34.3% in comparison to control (T1) on the last day of storage. Other treatments showed intermediate effects. The results suggest potential beneficial influence of synergistic treatment of polyamines, particularly spermine 1.5 mM with chitosan in extending shelf life of bell pepper by about 28 days relative to control with notable preservation of bioactive compounds, antioxidant enzymes and slowing senescence indicators over untreated fruit.

Polyamines from myeloid-derived suppressor cells promote Th17 polarization and disease progression

Myeloid-derived suppressor cells (MDSCs) are a group of immature myeloid cells that play an important role in diseases. MDSCs promote Th17 differentiation and aggravate systemiclupus erythematosus (SLE) progression by producing arginase-1 to metabolize arginine. However, the metabolic regulators remain unknown. Here, we report that MDSC derivative polyamines can promote Th17 differentiation via miR-542-5p invitro. Th17 polarization was enhanced in response to polyamine treatment or upon miR-542-5p overexpression. The TGF-β/SMAD3 pathway was shown to be involved inmiR-542-5p-facilitated Th17 differentiation. Furthermore, miR-542-5p expression positively correlated with the levels of polyamine synthetases in peripheral blood mononuclear cells of patients with SLE as well as disease severity. In humanized SLE model mice, MDSC depletion decreased the levels of Th17 cells, accompanied by reduced expression of miR-542-5p and these polyamine synthetases. In addition, miR-542-5p expression positively correlated with the Th17 level and disease severity in both patients and humanized SLE mice. Together, our data reveal a novel molecular pathway by which MDSC-derived polyamine metabolism enhances Th17 differentiation and aggravates SLE.

Role of Post-harvest Treatment of Polyamines on Physico-physiological Qualities of Papaya (Carica papaya L.) Fruits Var. Red Lady during Ambient Storage

Polyamines are the natural compound, act as anti-senescent agents, reduce rate of respiration, delay ethylene production, retard colour change, maintain fruit firmness. Show that plays a pivotal role in postharvest life of fruits and vegetables. The objective of this study was to investigate the effect of post-harvest application of polyamines in different concentration on physico-physiological quality parameters of papaya fruits during ambient storage (33-36oC). Papaya fruits are treated with different concentration of polyamines i.e., T2-0.50mM Spermine, T3- 1.0mM Spermine,T4- 1.5mM Spermine,T5- 0.50 mMSpermidine, T6- 1 mM Spermidine,T7- 1.5mM Spermidine,T8- 2 mM Putrescine,T9- 3 mM Putrescine,T10- 4 mM Putrescine and T1-Control. Among the treatments, papaya fruits treated with 4 mM of Putrescine (T10) recorded significantly minimum physiological loss in weight, respiration rate and colourvalues (L*, a*, b*) of peel and pulp, fruit disease index and maximum firmness, shelf life compared to control (T1). Hence it is confirmed from the study that Putrescine at 4mM (T10) was found to be effective in delaying the physico-chemical and physiological process of papaya fruit cv. Red Lady.

Expression of Polyamine Oxidase in Fibroblasts Induces MMP-1 and Decreases the Integrity of Extracellular Matrix.

Polyamine oxidase (PAOX) (N1-acetylpolyamine oxidase) is a major enzyme in the polyamine catabolism pathway that generates hydrogen peroxide. Hydrogen peroxide plays a crucial role in skin aging via extracellular matrix (ECM) degradation by increasing the matrix metalloproteinase-1 (MMP-1) levels. We analyzed the integrity of the ECM in foreskin fibroblasts using PAOX expression. PAOX increased the MMP-1 secretion and type Ι collagen degradation in 2D and 3D cultures of fibroblasts, respectively. Similarly, PAOX overexpression increased the messenger ribonucleic acid (mRNA) level of MMP-1. PAOX expression induced polyamine catabolism, decreased the spermine levels, and increased the putrescine levels. However, the exogenous polyamine treatment did not change the MMP-1 and type I collagen levels as much as PAOX expression. PAOX expression increased the reactive oxygen species (ROS) production in fibroblasts, and exogenous hydrogen peroxide increased both the ROS production and MMP-1 secretion. Furthermore, N-acetylcysteine, an antioxidant, reversed the PAOX-induced ROS production and MMP-1 secretion. PAOX induced the signaling pathways that activate activator protein-1 (AP-1) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), which are important transcription factors for MMP-1 transactivation. We concluded that PAOX increased the ROS levels in fibroblasts, leading to an increase in MMP-1 expression. Therefore, we propose that PAOX is a potential target molecule in protecting the ECM integrity.

Light Spectral Composition Modifies Polyamine Metabolism in Young Wheat Plants.

Although light-emitting diode (LED) technology has extended the research on targeted photomorphogenic, physiological, and biochemical responses in plants, there is not enough direct information about how light affects polyamine metabolism. In this study, the effect of three spectral compositions (referred to by their most typical characteristic: blue, red, and the combination of blue and red [pink] lights) on polyamine metabolism was compared to those obtained under white light conditions at the same light intensity. Although light quality induced pronounced differences in plant morphology, pigment contents, and the expression of polyamine metabolism-related genes, endogenous polyamine levels did not differ substantially. When exogenous polyamines were applied, their roborative effect were detected under all light conditions, but these beneficial changes were correlated with an increase in polyamine content and polyamine metabolism-related gene expression only under blue light. The effect of the polyamines on leaf gene expression under red light was the opposite, with a decreasing tendency. Results suggest that light quality may optimize plant growth through the adjustment of polyamine metabolism at the gene expression level. Polyamine treatments induced different strategies in fine-tuning of polyamine metabolism, which were induced for optimal plant growth and development under different spectral compositions.

Metabolomics and lipidomics insight into the effect of different polyamines on tomato plants under non-stress and salinity conditions

Polyamines (PAs) are key signaling molecules involved in plant growth and stress acclimation processes. This work investigated the effect of spermidine, spermine, and putrescine (alone and in a mixture) in tomato plants using a combined metabolomics and lipidomics approach. The experiments were carried out under non-stress and 100 mM NaCl salinity conditions. Shoot and root biomass, as well as SPAD values, were increased by the application of exogenous PAs but with differences across treatments. Similarly, root length density (F: 34, p < 0.001), average root diameter (F: 14, p < 0.001), and very fine roots (0.0–0.5 mm) increased in PA-treated plants, compared to control. Metabolomics and lipidomics indicated that, despite being salinity the hierarchically prevalent factor, the different PA treatments imposed distinct remodeling at the molecular level. Plants treated with putrescine showed the broader modulation of metabolite profile, whereas spermidine and spermine induced a comparatively milder effect. The pathway analysis from differential metabolites indicated a broad and multi-level intricate modulation of several signaling molecules together with stress-related compounds like flavonoids and alkaloids. Concerning signaling processes, the complex crosstalk between phytohormones (mainly abscisic acid, cytokinins, the ethylene precursor, and jasmonates), and the membrane lipids signaling cascade (in particular, sphingolipids as well as ceramides and other glycerophospholipids), was involved in such complex response of tomato to PAs. Interestingly, PA-specific processes could be observed, with peculiar responses under either control or salinity conditions.

Nucleosome destabilization by polyamines

The roles and molecular interactions of polyamines (PAs) in the nucleus are not fully understood. Here their effect on nucleosome stability, a key regulatory factor in eukaryotic gene control, is reported, as measured in agarose embedded nuclei of H2B-GFP expressor HeLa cells. Nucleosome stability was assessed by quantitative microscopy [1,2] in situ, in close to native state of chromatin, preserving the nucleosome constrained topology of the genomic DNA. A robust destabilizing effect was observed in the millimolar concentration range in the case of spermine, spermidine as well as putrescine, which was strongly pH and salt concentration-dependent, and remained significant also at neutral pH. The integrity of genomic DNA was not affected by PA treatment, excluding DNA break-elicited topological relaxation as a factor in destabilization. The binding of PAs to DNA was demonstrated by the displacement of ethidium bromide, both from deproteinized nuclear halos and from plasmid DNA. The possibility that DNA methylation patterns may be influenced by PA levels is contemplated in the context of gene expression and DNA methylation correlations identified in the NCI-60 panel-based CellMiner database: methylated loci in subsets of high-ODC1 cell lines and the dependence of PER3 DNA methylation on PA metabolism.

Dynamic Mitochondrial Proteome Under Polyamines Treatment in Cardiac Aging.

Age-related alteration of mitochondria causes impaired cardiac function, along with cellular and molecular changes. Polyamines can extend the life span in mice. However, whether polyamines can affect the dynamic mitochondrial proteome, thereby preventing age-related changes in cardiac function and cardiac aging, remains unclear. In this study, we found that spermine (Spm) and spermidine (Spd) injection for 6 weeks could prevent 24-month-old rats heart dysfunction, improve mitochondrial function, and downregulate apoptosis. Using iTRAQ tools, we identify 75 mitochondrial proteins of statistically significant alteration in aging hearts, which mainly participate in important mitochondrial physiological activity, such as metabolism, translation, transport, apoptosis, and oxidative phosphorylation. Moreover, four proteins of differential expression, pyruvate dehydrogenase kinase (PDK4), trifunctional enzyme subunit alpha (HADHA), nicotinamide nucleotide transhydrogenase (NNT), and Annexin6, which were significantly associated with heart aging, were validated by Western blotting. In vitro, we further demonstrated polyamines could retard cardiomyocytes aging through downregulating the expression of PDK4 and thereby inhibiting cell apoptosis. In summary, the distinct mitochondrial proteins identified in this study suggested some candidates involved in the anti-aging of the heart after polyamines treatment, and PDK4 may provide molecular clues for polyamines to inhibit apoptosis and thus retard aging-induced cardiac dysfunction.

Putrescine: A Key Metabolite Involved in Plant Development, Tolerance and Resistance Responses to Stress.

Putrescine (Put) is the starting point of the polyamines (PAs) pathway and the most common PA in higher plants. It is synthesized by two main pathways (from ornithine and arginine), but recently a third pathway from citrulline was reported in sesame plants. There is strong evidence that Put may play a crucial role not only in plant growth and development but also in the tolerance responses to the major stresses affecting crop production. The main strategies to investigate the involvement of PA in plant systems are based on the application of competitive inhibitors, exogenous PAs treatments, and the most efficient approaches based on mutant and transgenic plants. Thus, in this article, the recent advances in understanding the role of this metabolite in plant growth promotion and protection against abiotic and biotic stresses will be discussed to provide an overview for future research.

ATP13A3 facilitates polyamine transport in human pancreatic cancer cells

The purpose of this study is to provide an increased understanding of the molecular mechanisms responsible for mammalian polyamine transport, a process that has been a long-standing ‘black box’ for the polyamine field. Here, we describe how ATP13A3, a P-type ATPase, functions as a polyamine transporter in response to different polyamine stimuli and polyamine-targeted therapies in highly proliferating pancreatic cancer cells. We assessed the expression, cellular localization and the response of the human ATP13A3 protein to polyamine treatments in different pancreatic cancer cell lines using Western blot and immunofluorescence microscopy. Using CRISPR mutagenesis and radiolabeled polyamine uptake assays, we investigated the role of ATP13A3 protein in polyamine transport. Highly metastatic cancer cells with high polyamine import express higher levels of the full-length ATP13A3 compared to cells with slow proliferation and low import activity. Highlighting its role in polyamine trafficking, the localization of ATP13A3 is altered in the presence of polyamine stimuli and polyamine-targeted therapies in these cells. Using CRISPR mutagenesis, we demonstrate that the first membrane-associated domain of this protein is critical and indispensable for its function as a spermidine and spermine transporter in cells. Further analysis of existing databases revealed that pancreatic cancer patients with high expression of ATP13A3 have decreased overall survival consistent with the role of intracellular polyamines in supporting tumor growth. Our studies shed light on the mysterious polyamine transport process in human cells and clearly establishes ATP13A3 as an intrinsic component of the spermidine and spermine transport system in humans.

The Complex Metabolomics Crosstalk Triggered by Four Molecular Elicitors in Tomato.

The elicitation of plant secondary metabolism may offer interesting opportunities in the framework of sustainable approaches in plant science and in terms of their ability to prime resistance to biotic and abiotic stressors. The broad metabolic reprogramming triggered by different molecular elicitors, namely salicylate (SA), polyamines (PAs), and chitosan, was comprehensively investigated using a metabolomics approach and the tomato (Solanum lycopersicum L.) as the model crop. Six different treatments were compared: a negative control (no treatments), a second negative control treated with 1 M acetic acid (the reference for chitosan, since chitosan was solubilized in acetic acid), and four molecular elicitors, 1 mM 2,1,3-benzothiadiazole (BTH, a positive control), 10 mg/mL chitosan, 0.01 mM SA, and a 0.1 mM PA (putrescine, spermidine, and spermine). All treatments determined a slight increase in biomass, in particular following PA treatment. A broad reprogramming of secondary metabolism could be observed, including membrane lipid remodeling, phenylpropanoid antioxidants, and phytohormone crosstalk. Overall, our results suggest that PAs, SA, and BTH shared a systemic acquired resistance (SAR)-related response, whereas chitosan induced a more distinct induced systemic resistance (ISR)-like jasmonate-related response. These results pave the way towards the possible use of elicitors as a sustainable tool in plant science and agriculture by increasing crop resilience to biotic and abiotic stressors without detrimental effects on plant biomass.

Exogenous polyamine treatment preserves postharvest quality, antioxidant compounds and reduces lipid peroxidation in black plum fruit

Black plum (Syzygium cumini L. Skeels) is a tropical and sub-tropical fruit having several medicinal properties, especially in curing diabetes. Due to non-climacteric nature, the fruit is harvested at ripe stage. However, presence of thin skin and rapid softening make the fruit highly susceptible to moisture loss and microbial attack, which drastically reduce its shelf life. Black plum, due to its high perishability cannot be stored more than 2 – 3 days at ambient conditions. In the present study, the effect of pre-storage polyamines treatment on quality and storability of black plum fruit was investigated. Ripe fruits were treated with putrescine (PUT) and spermine (SPM) each at 0.5 mM and 1.0 mM concentration by immersion method while, control fruit were treated with distilled water. The fruit were stored at ambient conditions (27 ± 3 °C, 85 ± 5% RH) for 6 days. Results revealed that 1.0 mM PUT treatment was most effective in minimizing weight loss and spoilage of about 1.5-fold compared to control. The treated fruits also retained higher anthocyanins and minimized lipid peroxidation than control. The loss of bioactive compounds like total phenolics, flavonoids, ascorbic acid and antioxidant capacity also minimized in response to polyamine treatments. The soluble solids content retained higher in 1.0 mM PUT-treated fruits but, polyamine treatments did not affect acid content. The findings of the study can be beneficially exploited in extending storability, long distant marketing and reducing postharvest loss of black plum fruit.

Polyamine Metabolism under Different Light Regimes in Wheat.

Although the relationship between polyamines and photosynthesis has been investigated at several levels, the main aim of this experiment was to test light-intensity-dependent influence of polyamine metabolism with or without exogenous polyamines. First, the effect of the duration of the daily illumination, then the effects of different light intensities (50, 250, and 500 μmol m–2 s–1) on the polyamine metabolism at metabolite and gene expression levels were investigated. In the second experiment, polyamine treatments, namely putrescine, spermidine and spermine, were also applied. The different light quantities induced different changes in the polyamine metabolism. In the leaves, light distinctly induced the putrescine level and reduced the 1,3-diaminopropane content. Leaves and roots responded differently to the polyamine treatments. Polyamines improved photosynthesis under lower light conditions. Exogenous polyamine treatments influenced the polyamine metabolism differently under individual light regimes. The fine-tuning of the synthesis, back-conversion and terminal catabolism could be responsible for the observed different polyamine metabolism-modulating strategies, leading to successful adaptation to different light conditions.