Effect of Putrescine Treatment on Chilling Injury, Fatty Acid Composition and Antioxidant System in Kiwifruit

Eco-friendly managements and molecular mechanisms for improving postharvest quality and extending shelf life of kiwifruit: A review

Kiwifruit (Actinidia spp.) is a commercially important horticultural fruit crop worldwide. Kiwifruit contains numerous minerals, vitamins, and dietary phytochemicals, that not only responsible for the flavor but can also serve as adjuncts in the treatment of diabetes, digestive disorders, cardiovascular system, cancer and heart disease. However, fruit quality and shelf life affect consumer's acceptance and production chain. Understanding the methods of fruit storage preservation, as well as their biochemical, physiological, and molecular basis is essential. In recent years, eco-friendly (comprehensive and environmentally friendly) treatments such as hot water, ozone, chitosan, quercetin, and antifungal additive from biocontrol bacteria or yeast have been applied to improve postharvest fruit quality with longer shelf life. This review provides a comprehensive overview of the latest advancements in control measures, applications, and mechanisms related to water loss, chilling injury, and pathogen diseases in postharvest kiwifruit. Further studies should utilize genome editing techniques to enhance postharvest fruit quality and disease resistance through site-directed bio-manipulation of the kiwifruit genome.

MaC2H2-like regulates chilling stress response of ‘Fenjiao’ banana by modulating flavonoid synthesis and fatty acid desaturation

Chilling injury (CI) is a major problem that affects fruit quality and ripening. Herein, chilling stress severely inhibited the expression of transcription factor MaC2H2-like. MaC2H2-like activates the expression of genes associated with flavonoid synthesis (MaC4H-like1, Ma4CL-like1, MaFLS, and MaFLS3) and fatty acid desaturation (MaFAD6-2 and MaFAD6-3), the leading indicators of chilling tolerance. MaC2H2-like interacts with MaEBF1 and boosts the transcriptional activity of MaFAD6-2, MaFAD6-3, Ma4CL-like1, and MaFLS. The overexpression of MaC2H2-like reduced fruit CI, induced the expression of these genes and increased the content of flavonoid and unsaturated fatty acid. Meanwhile, the silencing of MaC2H2-like increased fruit CI and downregulated the expression of those genes and reduced the content of flavonoid and unsaturated fatty acid. These results indicate that MaC2H2-like function as new player in modulating fruit CI by regulating flavonoid synthesis and fatty acid desaturation. MaC2H2-like could be a useful candidate gene for improving cold tolerance in 'Fenjiao' banana.

γ-Aminobutyric acid treatment induced chilling tolerance in postharvest peach fruit by upregulating ascorbic acid and glutathione contents at the molecular level

Peach fruit was treated with 5 mM γ-aminobutyric acid (GABA) to further investigate the mechanism by which GABA induced chilling tolerance. Here, we found that GABA not only inhibited the occurrence of chilling injury in peach fruit during cold storage but also maintained fruit quality. Most of the ascorbic acid (AsA) and glutathione (GSH) biosynthetic genes were up-regulated by GABA treatment, and their levels were increased accordingly, thus reducing chilling damage in treated peaches. Meanwhile, the increased transcript of genes in the AsA-GSH cycle by GABA treatment was also related to the induced tolerance against chilling. GABA treatment also increased the expression levels of several candidate ERF transcription factors involved in AsA and GSH biosynthesis. In conclusion, our study found that GABA reduced chilling injury in peach fruit during cold storage due to the higher AsA and GSH contents by positively regulating their modifying genes and candidate transcription factors.

Copper Amine Oxidase (CuAO)-Mediated Polyamine Catabolism Plays Potential Roles in Sweet Cherry (Prunus avium L.) Fruit Development and Ripening

Copper amine oxidases (CuAOs) play important roles in PA catabolism, plant growth and development, and abiotic stress response. In order to better understand how PA affects cherry fruit, four potential PavCuAO genes (PavCuAO1–PavCuAO4) that are dispersed over two chromosomes were identified in the sweet cherry genome. Based on phylogenetic analysis, they were classified into three subclasses. RNA-seq analysis showed that the PavCuAO genes were tissue-specific and mostly highly expressed in flowers and young leaves. Many cis-elements associated with phytohormones and stress responses were predicted in the 2 kb upstream region of the promoter. The PavCuAOs transcript levels were increased in response to abscisic acid (ABA) and gibberellin 3 (GA₃) treatments, as well as abiotic stresses (NaCl, PEG, and cold). Quantitative fluorescence analysis and high-performance liquid chromatography confirmed that the Put content fell, and the PavCuAO4 mRNA level rose as the sweet cherry fruit ripened. After genetically transforming Arabidopsis with PavCuAO4, the Put content in transgenic plants decreased significantly, and the expression of the ABA synthesis gene NCED was also significantly increased. At the same time, excessive H₂O₂ was produced in PavCuAO4 transiently expressed tobacco leaves. The above results strongly proved that PavCuAO4 can decompose Put and may promote fruit ripening by increasing the content of ABA and H₂O₂ while suppressing total free PA levels in the fruit.

Role of MaABI5-like in abscisic acid-induced cold tolerance of 'Fenjiao' banana fruit

Abscisic acid (ABA) is a phytohormone essential for plants to respond to various environmental stresses, and abscisic acid-insensitive 5 (ABI5) is a basic leucine zipper transcription factor of the ABA signaling pathway. Exogenous ABA induces cold tolerance in bananas; however, the role of MaABI5-like in ABA-induced cold tolerance remains unexplored. The present study found that exogenous ABA alleviated chilling injury of 'Fenjiao' banana, induced the accumulation of endogenous ABA, unsaturated fatty acids, and flavonoid content, and reduced the saturated fatty acid content. Moreover, ABA treatment upregulated the transcription levels of MaABI5-like, fatty acid desaturation genes, and flavonoid synthesis-related genes during cold storage. More interestingly, MaABI5-like directly interacted with the promoter of genes related to fatty acid desaturation (MaFAD3-1, MaFAD3-4, MaFAD3-5, MaFAD6-2, MaFAD6-3) and flavonoid synthesis (MaPAL-like, MaPAL-like1, MaC4H-like3, Ma4CL-like1, Ma4CL-like10, MaCHS6-4-like, and MaFLS) and activated their expressions. Furthermore, the transient overexpression of MaABI5-like in 'Fenjiao' banana fruit and ectopic expression in tomato plants enhanced cold tolerance and upregulated fatty acid desaturation and flavonoid synthesis-related gene transcript levels. The reduced expression of MaABI5-like by virus-induced gene silencing in 'Fenjiao' banana increased chilling injury and downregulated the expression of fatty acid desaturation and flavonoid synthesis-related genes. Thus, the study indicates that MaABI5-like regulates ABA-induced cold tolerance by increasing unsaturated fatty acid and flavonoid content.

PpCBF6 Is Involved in Phytosulfokine α-Retarded Chilling Injury by Suppressing the Expression of PpLOX5 in Peach Fruit

The involvement of PpCBF6 in phytosulfokine α (PSKα)-ameliorated chilling injury (CI) by suppressing the expression of lipoxygenase 5 (LOX5) in peach fruit was revealed. The peaches were immersed in distilled water and PSKα solution. PSKα application inhibited the progression of CI index and weight loss, and the reduction of firmness and total soluble solids content in peaches. The endogenous PSKα accumulation and gene expression of PSK receptor 1 (PSKR1) and PSKR2 were up regulated by PSKα application. The superoxide anion (O2 -) production rate, hydrogen peroxide (H2O2) production and reactive oxygen species (ROS) content decreased by PSKα application. Furthermore, PSKα application reduced the gene expression of 12 PpLOXs and LOX activity. The gene expression of 6 PpCBFs was enhanced by PSKα application. Importantly, after PSKα application, among 12 PpLOXs, the decrease in gene expression of PpLOX5 was the lowest, and among 6 PpCBFs, the increase in gene expression of PpCBF6 was the highest. Further results suggested that PpCBF6 bound to the C-repeat/dehydration responsive element (CRT/DRE) motif in PpLOX5 promoter, and repressed its transcription. Thus, PpCBF6 was involved in the PSKα-retarded CI by inhibiting the expression of PpLOX5 in peaches.

Fatty acid composition in relation to chilling susceptibility of blood orange cultivars at different storage temperatures

Fatty acid composition in the peel of four blood orange cultivars ('Moro', 'Tarocco', 'Sanguinello', and 'Sanguine') was identified and quantified by gas chromatography-mass spectrometry (GC-MS), in order to find its correlation with chilling susceptibility at harvest time and after 180 days of storage at 2 and 5 °C (2 days at 20 °C for shelf life). Twelve fatty acids were detected including 6 saturated (SFA) and 6 unsaturated (UFA), from which 4 monounsaturated (MUFA) and 2 polyunsaturated (PUFA) fatty acids occurred. The major fatty acids were palmitic, linoleic, and linolenic acids. The chilling injury (CI) index was significantly higher at 2 than 5 °C for all cultivars, with 'Sanguinello' being the more tolerant cultivar. The multivariate statistical analyses showed that 'Sanguinello' had the highest UFA, UFA/SFA ratio, and the lowest SFA, while 'Moro' as a cold sensitive cultivar had the highest SFA, the lowest UFA, and UFA/SFA ratio. Our findings revealed that the higher level of PUFAs (linoleic and linolenic acids) and enhancement of the UFA/SFA ratio are considered the most main adaptive mechanism under low temperatures of storage.

The Co-regulation of Ethylene Biosynthesis and Ascorbate-Glutathione Cycle by Methy Jasmonate Contributes to Aroma Formation of Tomato Fruit during Postharvest Ripening

Currently, many fruits are always harvested at the early ripening stage to reduce postharvest losses followed by 1-methylcyclopropene (1-MCP) or ethephon treatment. However, harvesting at the early ripening stage adversely affects fruit quality, especially for the aroma. Methyl jasmonate (MeJA) treatment could induce the biosynthesis of bioactive compounds and maintain postharvest fruit quality. In the present work, the contributions of MeJA to tomato fruit quality during postharvest ripening were studied. The results showed that MeJA treatment significantly promoted the accumulation of volatile organic components (VOCs) by inducing the activities of enzymes related to lipoxygenase pathway and ethylene biosynthesis, whereas 1-MCP treatment largely inhibited the accumulation of VOCs by inhibiting activities of those enzymes. Although the application of ethephon also induced activities of the above enzymes in comparison with control, no significant differences were observed between the VOCs contents of the control and ethephon-treated fruit. Further study revealed that the ethephon treatment resulted in the enhancement of electrical conductivity and malondialdehyde content. Conversely, MeJA treatment inhibited the superoxide anion radical and hydrogen peroxide by regulating the ascorbate-glutathione cycle and further inhibited the enhancement of electrical conductivity and malondialdehyde content, which might be one of the most important reasons why the VOCs contents in fruit treated with ethephon were lower than those in MeJA-treated fruit. Thus, it is considered that MeJA treatment may be an effective and promising strategy to regulate postharvest tomato fruit quality, especially for the aroma, by regulating the ascorbate-glutathione cycle and ethylene biosynthesis.

Postharvest melatonin treatment reduces chilling injury in sapota fruit

BACKGROUND

Sapota is a popular tropical fruit characterized by a very short postharvest life. Low-temperature storage prolongs postharvest life of sapota fruit, but chilling injury symptoms can develop if the storage temperature is less than 14 °C. There have been no reports on the effects of postharvest melatonin application on the development of chilling injury in sapota fruit during cold storage. The objective of this study was to investigate the effects of different concentrations of postharvest melatonin application (0, 30, 60 and 90 μmol L^-1 ) during cold storage (8 °C) for up to 30 days with an additional 1-day shelf life at ambient temperature.

RESULTS

All melatonin treatments reduced chilling injury symptoms, reduced electrolyte leakage, malondialdehyde (MDA) content, H₂ O₂ and superoxide anion (O₂ ^- ), and increased proline content and the activity of superoxide dismutase (SOD), catalase (CAT) and γ-aminobutyric acid (GABA), and reduced the activities of phospholipase D (PLD) and lipoxygenase (LOX) compared to the control.

CONCLUSION

Postharvest melatonin treatment could be a useful strategy for reducing chilling injury during cold storage and transport of sapota fruit. The results indicate that melatonin reduces chilling injury of sapota fruit through maintaining membrane integrity, SOD and CAT activities, and reducing PLD and LOX activities. © 2019 Society of Chemical Industry.

The membrane lipid metabolism in horticultural products suffering chilling injury

Horticultural commodities suffer chilling injury following exposure to extremely low temperatures, which results in visible symptoms and considerable quality loss. Therefore, it is of significance to understand the mechanism of this physiological disorder and to develop effective strategies to control it. Chilling stress causes alteration in structure and function of the plasma membrane, which is assumed to be the primary event in response to cold stress. During this process, the membrane lipid metabolism plays a pivotal role in membrane fluidity and stability. In this review, we summarized the possible roles of membrane lipid metabolism in the development of chilling injury, having the potential for developing effective strategies to alleviate chilling injury in horticultural products under refrigerated storage in practice.

The Effects of Salicylic Acid and Its Derivatives on Increasing Pomegranate Fruit Quality and Bioactive Compounds at Harvest and During Storage

In the present research two experiments were performed to evaluate the effect of pre-harvest salicylic acid (SA), acetyl salicylic acid (ASA), and methyl salicylate (MeSa), applied as a foliar spray to pomegranate "Mollar de Elche," on crop yield, fruit quality parameters, and bioactive compounds at harvest and during storage. In the 2017 experiment, trees were treated with SA, ASA, and MeSa at 1, 5, and 10 mM and a higher crop yield (kg tree^-1 and number of harvested fruit tree^-1) and quality parameters (firmness, aril color, and individual sugars and organic acids) at harvest were obtained, as well as a higher concentration of phenolics, anthocyanins, and ascorbic acid. The best results were achieved with 10 mM dose of the three assayed compounds, which was chosen for the 2018 experiment, and results for crop yield and fruit quality attributes were confirmed. These quality traits and the concentration of phenolics, anthocyanins, and ascorbic acid were maintained at higher levels in pomegranate fruit from treated trees than in controls during prolonged storage at 10°C. In addition, the effects of salicylate treatments on increasing total and individual anthocyanin concentration in pomegranate arils led to arils with a deeper red color (Graphical Abstract) and, in turn, fruit that would be more appreciated in the international market. This fact, together with the increased crop yield, would contribute to the increased profit of this crop. Thus, pre-harvest treatment with salicylates, and especially SA at 10 mM concentration, could be a safe, natural, and new tool to improve fruit quality and its content on antioxidant compounds with health beneficial effects (namely, ascorbic acid, phenolics, and anthocyanins) at harvest and during storage.

Actinidia chinensis Planch.: A Review of Chemistry and Pharmacology

Actinidia chinensis Planch. (A. chinensis), commonly known as Chinese kiwifruit, is a China native fruit, which becomes increasingly popular due to attractive economic, nutritional, and health benefits properties. The whole plant including fruits, leaves, vines, and roots of A. chinensis are used mainly as food or additive in food products and as folk medicine in China. It is a good source of triterpenoids, polyphenols, vitamin C, carbohydrate, amino acid, and minerals. These constituents render the A. chinensis with a wide range of pharmacological properties including antitumor, antioxidant, anti-inflammatory, immunoregulatory, hypolipemic, antidiabetic, and cardiovascular protective activities, suggesting that it may possibly be value in the prevention and treatment of pathologies associated to cancer, oxidative stress, and aging. This minireview provides a brief knowledge about the recent advances in chemistry, biological activities, utilization, and storage of Chinese kiwifruit. Future research directions on how to better use of this crop are suggested.

Down-regulation of arginine decarboxylase gene-expression results in reactive oxygen species accumulation in Arabidopsis

Arabidopsis amiR:ADC-L2 is a non-lethal line with several developmental defects, it is characterized by a drastic reduction in free polyamine content. Herein, we found that catalase application had growth-promoting effects in amiR:ADC-L2 and parental Ws seedlings. Differences in ROS content between amiR:ADC-L2 and Ws seedlings were detected. Increased H2O2 levels were found in the amiR:ADC-L2, as well as low AtCAT2 gene expression and reduced catalase activity. Estimation of polyamine oxidase activity in amiR:ADC-L2 line indicated that the over-accumulation of H2O2 is independent of polyamine catabolism. However, increments in NADPH oxidase activity and O2•- content could be associated to the higher H2O2 levels in the amiR:ADC-L2 line. Our data suggest that low polyamine levels in Arabidopsis seedlings are responsible for the accumulation of ROS, by altering the activities of enzymes involved in ROS production and detoxification.

Hypolipidemic effect of Fragarianilgerrensis Schlecht. medicine compound on hyperlipidemic rats

BACKGROUND

Fragarianilgerrensis Schlecht. medicine compound (FN-MC) is a kind of Chinese herbs' compound consisted of Fragarianilgerrensis Schlecht. and Centella asiatica (L.) Urban. The study was to investigate the hypolipidemia effect of FN-MC in a hypolipidemic rat model.

METHODS

Male SD rats were randomly divided into five groups: normal-fat diet (NFD) group, high-fat diet (HFD) group, FN-MC (2 g/Kg) group, FN-MC (4 g/Kg) group and simvastatin (PDC) group. After FN-MC treatment, body weight, food intake, serum and hepatic biochemistry parameters of rats were measured and the pathological changes of liver and its cells were observed by optical microscope and transmission electron microscopy.

RESULTS

The results showed that FN-MC significantly decreased the levels of serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL-C), apolipoprotein B (ApoB) and hepatic malondialdehyde (MDA), while increased serum high-density lipoprotein (HDL-C), apolipoprotein A1 (ApoA1) and hepatic Superoxide Dismutase (SOD). FN-MC also improved the structure of liver and decreased the lipid drops in the cytoplasm significantly. In addition, FN-MC significantly decreased the weight gain and had no significant effects on food intake.

CONCLUSIONS

The study suggested that FN-MC exhibited strong ability to improve the dyslipidemia and prevent hepatic fatty deposition in rats fed with high-fat diet. Meanwhile, FN-MC exerted anti-obesity and antioxidant properties.

HIGHLIGHTS

Fragarianilgerrensis Schlecht. medicine compound possesses a hypolipidemic effect on hyperlipidemic rat model Fragarianilgerrensis Schlecht. medicine compound administration improves the antioxidant capacity of rats Fragarianilgerrensis Schlecht. medicine compound prevents hepatic fatty deposition.

Hypolipidemic effects of total flavonoide extracted from the leaves of Actinidiakolomikta in rats fed a high-fat diet

OBJECTIVES

This study was to investigate the antihyperlipidemic and antioxidant effect of total flavonoid extract from Actinidiakolomikta (TFAK) in hyperlipidemia induced by a high-fat diet.

MATERIALS AND METHODS

Male SD rats were randomly divided into 6 groups: normal group, model (hyperlipidemic diet) group, hyperlipedemic diet supplemented with TFAK (50, 100 and 200 mg/kg) and simvastatin (30 mg/kg) groups. The rats were administrated TFAK by oral for 28 days. Body weight, total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), superoxide dismutase (SOD), catalase(CAT), glutathione peroxidase(GSH-Px) and malondialdehyde (MDA) were measured. The atherogenic index (AI) and coronary risk index (CRI) were calculated. The activity of hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase in hepatic tissue was examined. Histopathologic changes were also checked.

RESULTS

The levels of TC, TG and LDL-c were increased in model group. Compared to the model group, TFAK reduced significantly the body weight, TC, TG, LDL-c, AI, CRI and elevated the level of HDL-c. Moreover, the activity of SOD was elevated significantly, whereas the content of MDA decreased. The activity of HMG-CoA reductase was also decreased. Morphological evaluation found that rats in model group developed a severe steatosis, but the severity of liver steatosis was ameliorated in TFAK treated groups. The possible mechanism may be associated with decrease HMG-CoA reductase activity.

CONCLUSION

Our results suggest that TFAK exerts strong antioxidant and lipid-lowering effects, prevents hepatic fatty deposition and regulates the HMG-CoA reductase.