•The chlorophyll content continuously declined during broccoli yellowing.•Jasmonic acid (JA) is involved in broccoli yellowing.•JA regulates chlorophyll degradation in broccoli.•Methyl jasmonate ...promoted chlorophyll reduction and accelerated broccoli yellowing.•Diethyldithiocarbamic acid, a JA synthesis inhibitor, delayed broccoli yellowing.
Chlorophyll degradation is the main reason for postharvest yellowing of broccoli. To uncover the role of jasmonic acid (JA) on the degradation of chlorophyll, broccoli flowers were treated with exogenous methyl jasmonate (MeJA) and diethyldithiocarbamic acid (DIECA). We found a surge of endogenous JA content with the yellowing process, and a significant correlation between JA and chlorophyll content. MeJA treatments led to increased endogenous JA, increased allene oxide cyclase (AOC) activity, and enhanced expression of JA synthesis genes. MeJA caused a stronger reduction in the maximum quantum yield (Fv/Fm), fluorescence decline ratio (Rfd), and total chlorophyll content, advanced the peak of pheide a oxygenase (PAO) activity, and up-regulated the expression of chlorophyll degradation genes. The DIECA treatment resulted in lower endogenous levels of JA, and AOC and 12-oxo-phytodienoic acid reductase (OPR) activity. This study revealed that the potential role of JA on broccoli yellowing is to promote the chlorophyll degradation.
•Energy metabolism may be involved in the development of CI in pear fruit.•1-MCP treatment of pear fruit alleviated chilling injury.•1-MCP could reduce CI development due to maintenance of higher ...level of energy charge.•1-MCP treated fruit had higher unsaturated/saturated fatty acid ratio.•1-MCP alleviated CI by inducing enzyme activity related to energy metabolism
This study investigated the effects of 1-methylcyclopropene (1-MCP) treatment on chilling injury (CI), energy metabolism, and membrane fatty acid content in harvested ‘Nanguo’ pears during the shelf life after cold storage at 0°C. 1-MCP treated fruit showed slower CI injury development, lower ion leakage and malondialdehyde accumulation, increased adenosine triphosphate content and energy charge during a 25 day shelf life period at 20°C. Activities of enzymes associated with energy metabolism, including H+-adenosine triphosphatase, Ca2+-adenosine triphosphatase, succinic dehydrogenase, and cytochrome C oxidase increased after 1-MCP treatment. The ratio of unsaturated to saturated fatty acids in 1-MCP-treated fruit was higher than that in control fruit. These results suggest that alleviation of CI after 1-MCP treatment might be due to enhanced energy metabolism-related enzyme activities and higher levels of energy and unsaturated to saturated fatty acid ratio.
•Pitting developed in blueberry fruit during shelf life.•We revealed changes in energy metabolism accompanying pitting developed in blueberry.•Energy shortages during shelf life corresponded to ...abnormalities in stress responses.
Low-temperature storage and transport of blueberries is widely practiced in commercial blueberry production. In this research, the storage life of blueberries was extended at low temperature, but fruit stored for 30d at 0°C pitted after 2d at room-temperature. Fruit cellular structure and physiological parameters accompanying pitting in blueberries were changed. The objective of this research was to characterise properties of energy metabolism accompanying pitting in blueberries during storage, including adenosine phosphates and mitochondrial enzymes involved in stress responses. Physiological and metabolic disorders, changes in cell ultrastructure, energy content and ATPase enzyme activity were observed in pitting blueberries. Energy shortages and increased activity of phenylalanine ammonia lyase (PAL) and lipoxygenase (LOX) were observed in fruit kept at shelf life. The results suggested that sufficient available energy status and a stable enzymatic system in blueberries collectively contribute to improve chilling tolerance, thereby alleviating pitting and maintaining quality of blueberry fruit in long-term cold storage.
Abstract
Bell peppers are vulnerable to low temperature (<7�C) and subject to chilling injury (CI). To elucidate the relationship between cell membrane lipid composition and CI, a membrane lipidomic ...approach was taken. In addition, we performed microstructural analysis and low-field nuclear magnetic resonance to better understand CI. We also monitored primary physiological metabolism parameters to explain lipidomics. Our study indicated that cellular structure damage was more serious at 4�C, mostly represented by damage to the plasmalemma and plastid degradation. Membrane lipidomic data analysis reveals monogalactosyldiacylglycerol, phosphatidylcholine, phosphatidylethanolamine and phosphatidic acid as crucial biomarkers during CI. Furthermore, the significant increase in proline, electrolyte leakage and phospholipase D in chilled fruits also proved that membrane lipid metabolism is involved in the response to low temperature stress. To our knowledge, this study is the first attempt to describe the CI mechanisms in bell peppers based on membrane lipidomics.
•Pitting in blueberries developed on removal from cold storage to shelf-life at room temperature.•Changes in antioxidative metabolism accompanied pitting development.•Pitting may be associated with ...reactive oxygen species and antioxidant systems.
Blueberries (Vaccinium spp. ‘LanFeng’) are harvested and consumed at maturation and have a short storage life at room temperature. Changes in blueberry quality and physiological parameters differ under room or low temperature storage conditions. The storage life of blueberries can be extended at low temperature, but pitting can develop associated with refrigeration, especially during subsequent shelf-life. The objective of this research was to understand the antioxidative metabolism accompanying pitting development of stored blueberry fruit, involving reactive oxygen species and antioxidant systems. Physiological and metabolic disorders, including low firmness, increased cell membrane electrolyte leakage and malondialdehyde (MDA) content, and changes in enzyme activity, were observed in pitting blueberries. Blueberries were stored at 20°C and 0°C for 10 days and 60 days, respectively. Hydrogen peroxide and superoxide radical production rate increased more rapidly during shelf-life after cold storage than at room temperature. On the other hand, blueberries during shelf-life after cold storage, when pitting occurred, had lower activity of antioxidant-related enzymes, including superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), than those stored at room temperature. The severity of pitting was paralleled by higher cell membrane electrolyte leakage and MDA content, and lower SOD, CAT, and APX activities.
•Pericarp browning after refrigeration is linked to mitochondrial damage and ROS.•Exogenous polyamines (PA) inhibit ROS generation and protect mitochondrial integrity.•PA treatment increases energy ...charge (EC) and promotes ATP biosynthesis in mitochondria.•Exogenous PA treatment ameliorates pericarp browning in refrigerated Nanguo pears.
Refrigeration is the most common way to store ‘Nanguo’ pears. However, their pericarps are prone to browning during the shelf life after refrigeration. In this study, we examined the effects of polyamines (PAs) on pericarp browning and analyzed their impact on mitochondrial morphology and function. Exogenous PAs substantially alleviated the onset and development of pericarp browning in pear fruit treated with them. PA content and the expression and activity of anabolic enzymes related to PAs increased, whereas the reactive oxygen species levels decreased. Moreover, the PA treatment preserved pericarp mitochondrial structure. Exogenous PA diminished the rate of increase and amplitude of mitochondrial membrane permeability transition pore opening and mitochondrial membrane permeability. To a certain extent, the PA treatment maintained mitochondrial energy levels. These results imply that exogenous PA treatment may be a strategy for ameliorating the browning of cold stored ‘Nanguo’ pears.
Long-term storage of pear fruit at low temperature can retard senescence but may result in pericarp browning. We previously reported that increasing endogenous γ-aminobutyrate (GABA) content by ...exogenous GABA treatment can maintain mitochondrial structure integrity, thereby alleviating pericarp browning of ‘Nanguo’ pears after cold storage. Here, we tested the effectiveness of Ca
2+
treatment on pericarp browning in relation to GABA biosynthesis. Fruit browning was reduced by treatment with Ca
2+
after 180 days of storage. Pericarp Ca
2+
and calmodulin content in treated fruit increased, and concomitantly, endogenous GABA content, key GABA synthesis-related enzyme activity, and gene expression were upregulated. Moreover, the mitochondrial structure in the pericarp tissue was found to be well preserved. Thus, Ca
2+
treatment effectively reduced pericarp browning of refrigerated ‘Nanguo’ pears owing to improvement in the GABA biosynthesis capacity in the fruit.
Rapid quality deterioration after harvest restricts the shelf life of broccoli, and reduces its commercial value. In this study, the effects of combined edible coating with chitosan and tea ...polyphenol (CTS + TP) on the post-harvest quality of broccoli were investigated. Results showed that the combined treatment of chitosan and tea polyphenol had better effects on the decay rate, weight loss rate, and respiratory intensity of broccoli than the single chitosan treatment and control. CTS + TP treatment mitigated the severity of broccoli yellowing, which was demonstrated by the higher hue angle, chlorophyll level, and strong red fluorescence emission of the treated samples, as well as delayed yellowing time compared to that observed in controls. Moreover, CTS + TP treatment better protected the sensory quality of the product, such as odor, hardness, and chewiness, and prevented evident changes. The vitamin C level in the treated samples was extremely higher, and the higher antioxidant capacity was also noted. The content of sulforaphane, the typical bioactive substance of broccoli, declined conspicuously in the yellowed broccoli, while the change was noticeably relieved by CTS + TP coating. The significantly upregulated expressions of
BoCYP83A1
,
BoMYB28
, and
BoMYR
in treated samples may have played an important role in the improvement of sulforaphane contents. These findings indicated that the edible coating with CTS + TP alleviated yellowing symptoms, improved the sensory quality, and enhanced the nutraceutical value of broccoli.
Blueberry (Vaccinium spp.) is a small berry with high economic value. Although cold storage can extend the storage time of blueberry to more than 60 days, it leads to chilling injury (CI) displaying ...as pedicle pits; and the samples of 0 °C-30 days was the critical point of CI. However, little is known about the mechanism and the molecular basis response to cold stress in blueberry have not been explained definitely. To comprehensively reveal the CI mechanisms in response to cold stress, we performed high-throughput RNA Seq analysis to investigate the gene regulation network in 0d (control) and 30d chilled blueberry. At the same time, the pitting and decay rate, electrolyte leakage (EL), malondialdehyde (MDA) proline content and GSH content were measured.
Two cDNA libraries from 0d (control) and 30d chilled samples were constructed and sequenced, generating a total of 35,060 unigenes with an N50 length of 1348 bp. Of these, 1852 were differentially expressed, with 1167 upregulated and 685 downregulated. Forty-five cold-induced transcription factor (TF) families containing 1023 TFs were identified. The DEGs indicated biological processes such as stress responses; cell wall metabolism; abscisic acid, gibberellin, membrane lipid, energy metabolism, cellular components, and molecular functions were significantly responsed to cold storage. The transcriptional level of 40 DEGs were verified by qRT-PCR.
The postharvest cold storage leads serious CI in blueberry, which substantially decreases the quality, storability and consumer acceptance. The MDA content, proline content, EL increased and the GSH content decreased in this chilled process. The biological processes such as stress responses, hormone metabolic processes were significantly affected by CI. Overall, the results obtained here are valuable for preventing CI under cold storage and could help to perfect the lack of the genetic information of non-model plant species.
Low-temperature storage is the primary postharvest method employed to maintain fruit quality and commercial value. However, pitting can develop during refrigeration, especially during the shelf life. ...In this study, a membrane lipidomic approach was employed to analyze the potential relationship between pitting and membrane lipid metabolism during post-cold-storage shelf life. We also determined the changes in ultrastructure and water distribution by low-field nuclear magnetic resonance (LF-NMR) and assessed the permeability of membrane, membrane lipid peroxidation, proline and malondialdehyde contents, and the activity and gene expression of phospholipase D and lipoxygenase, which are involved in membrane lipid metabolism. The results indicated that the changes in blueberry phospholipids during storage could be caused by cold stress. Furthermore, dehydration is a manifestation of chilling injury. Finally, the significant increase in electrolyte leakage, content of malondialdehyde and proline, and activity of phospholipase D and lipoxygenase in chilled blueberry also indicated that membrane lipid metabolism plays an important role in cold stress response.
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