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The contribution of CpERD and CpRAB on cold resistance of zucchini fruit under high relative humidity (HRH) storage was studied. The results showed that higher accumulations of CpRAB and CpERD were associated with decreased chilling injury in zucchini. HRH storage maintained a higher level of CpDREB1–5 expression and further activated the transcription of CpRAB and CpERD. CpRAB and CpERD exhibited protective roles in lactate dehydrogenase activity in vitro and cell activity of transformed E.coli in vivo under stresses. In addition, CpRAB and CpERD physically interacted with the CpSOD1 and CpCAT2 of zucchini. The transient expression of CpRAB and CpERD maintained higher antioxidant activities in tobacco leaves under cold stress. Taken together, the results suggested that accumulations of CpRAB and CpERD under HRH storage enhanced the chilling resistance of zucchini fruit, which may be due to their potential protective function of enzyme activities under cold and oxidative stress. • High RH maintained higher CpRAB/ERD accumulation in zucchini. • CpRAB and CpERD physically interacted with CpSOD1 and CpCAT2. • CpRAB/ERD enhanced antioxidant activities in tobacco leaves under cold stress. • CpRAB/ERD maintained LDH activities in vitro under cold and oxidative stress. • CpRAB/ERD protected cell activity of transformed E.coli model under stress. [ABSTRACT FROM AUTHOR]

The influence of mannose treatment on mitochondrial physiological parameters was investigated to postpone broccoli senescence. The results showed that mannose treatment could reduce the level of mitochondrial reactive oxygen species (ROS) to slow down the damage to its ultrastructure. Mannose inhibited malondialdehyde (MDA) accumulation and the decline of cytochrome c/a (Cyt c/a), and delayed the increase of mitochondrial membrane permeability. It also alleviated the over-opening of the mitochondrial membrane permeability transition pore (MPTP) by regulating expressions of MPTP component genes such as BoVDAC , BoHXK and BoANT. Moreover, mannose treatment improved the activities of mitochondrial antioxidant enzymes, including ascorbate oxidase (APX), superoxide dismutase (SOD), catalase (CAT), and ascorbic acid (AsA) content. Also, it increased the activities of succinate dehydrogenase (SDH), malate dehydrogenase (MDH), and Ca2+-ATPase, which were crucial for the mitochondrial energy metabolism. Taken together, our data indicated that mannose treatment inhibited the senescence of broccoli by maintaining the mitochondrial morphological structure and function. [Display omitted] • Mannose inhibited senescence of broccoli by regulating mitochondrial function. • Mannose treatment maintained the mitochondrial ultrastructure of broccoli. • Mannose alleviated the over-opening of MPTP in broccoli. • Mannose treatment regulates the expressions of BoVDAC , BoHXK , and BoANT. [ABSTRACT FROM AUTHOR]

The effect of blue light exposure on sugar metabolism and cryptochrome gene expression in postharvest Chinese bayberry fruit was investigated. Results showed blue light treatment significantly increased the contents of sucrose, fructose, and glucose in bayberries during storage. Expression analysis revealed that transcripts of three sucrose phosphate synthase ( MrSPS1 , MrSPS2 , and MrSPS3 ) were markedly induced by blue light treatment throughout the storage period, but increases in expression of two acid invertase genes ( MrINV2 and MrINV3 ) were detected only at the beginning of storage. Meanwhile, a hexokinase gene ( MrHXK1 ) and two genes of cryptochrome ( MrCRY1 and MrCRY2 ) were isolated from bayberry fruit. The expression levels of MrHXK1 and MrCRY1 were up-regulated during blue light exposure only at the end of storage; however, significantly higher amounts of MrCRY2 transcripts were found in blue light exposed-fruit throughout the storage period. Results suggest that blue light treatment increases the sugar content in postharvest bayberries during storage by regulating the expression levels of genes involved in sugar metabolism. Additionally, the enhancement of transcripts of MrCRY1 and MrCRY2 might also be associated with the increase in sugar content in blue light exposed fruit. [ABSTRACT FROM AUTHOR]

High relative humidity (RH) cold room (RH: 98 ± 2%) controlled by a 'dry fog' system and normal cold room (RH: 74 ± 2%) were used to store zucchini fruit to investigate the regulation of high RH on chilling tolerance and sugar and ethanol metabolisms under cold stress. High RH storage inhibited chilling injury (CI) and maintained higher activities of sucrose synthase-synthesis and sucrose phosphate synthase and contents of glucose, fructose and sucrose in zucchini fruit. Meanwhile, high RH-stored fruit exhibited lower activities of hexokinase, phosphofructokinase, and pyruvate kinase as compared with the control. Besides, the accumulation of acetaldehyde and ethanol under cold stress was decreased by high RH storage together with the inhibition of the increase in activities of alcohol dehydrogenase, pyruvate decarboxylase and expressions of related genes. Taken together, high RH storage enhanced chilling tolerance in zucchini fruit by maintaining high levels of soluble sugars and inhibiting ethanol production. • Zucchini fruit stored under high RH showed increased chilling tolerance. • High RH storage maintained higher levels of soluble sugars in zucchini fruit. • High RH storage regulated the activities of enzymes related to glycolysis. • High RH storage inhibited the ethanol fermentation in zucchini fruit. [ABSTRACT FROM AUTHOR]

Abstract: The effect of 1-methylcyclopropene (1-MCP) on senescence and quality maintenance of green bell pepper fruit was investigated. To explore the optimum concentration of 1-MCP to delay senescence, pepper fruit were treated with 0.5, 1.0 or 1.5μLL−1 1-MCP and then stored for 10d at 20°C. The results showed that the application of 1-MCP at 1.0μLL−1 was most effective in delaying senescence, manifested as chlorophyll degradation and increase in weight loss. 1-MCP treated peppers had higher levels of chlorophyll, protein and vitamin C and lower respiration rates and ethylene production compared with that in control peppers. In addition, 1-MCP enhanced activities of superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase and levels of polyamines including putrescine, spermidine and spermine. These results suggested that the delaying senescence of green bell pepper by 1-MCP treatment is associated with enhanced antioxidant enzyme activities and polyamine contents. [Copyright &y& Elsevier]

Abstract: The effect of heat treatment (38°C, 12h in air) and salicylic acid (SA, 1mM) either separately or combined, on internal browning (IB) in cold-stored peach fruit (Prunus persica Batsch) was investigated. The results showed that heat combined with SA treatment was the most effective method of alleviating IB in peach fruit during cold storage at 0°C. The activities of antioxidant enzymes such as superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase were significantly induced, while lipoxygenase activity was decreased by heat combined with an SA treatment. In addition, the combined treatment increased the levels of polyamines including putrescine, spermidine and spermine. These results suggest that the combination of heat and SA treatment may be a useful technique to alleviate IB in cold-stored peach fruit and the reduction in IB by the combined treatment may be due to the induction of antioxidant enzymes and increase in polyamine levels. [ABSTRACT FROM AUTHOR]

Abstract: Freshly harvested strawberry fruit were treated at ultrasonic powers from 250 to 450W at a constant frequency of 40kHz for different times (5–15min). Response surface methodology (RSM) based on a two factors three level central composite design was applied to optimize ultrasonic treatments on decay incidence, microbial population and quality maintenance of strawberries. According to response surface analysis, the optimal treatment parameters were an ultrasonic power of 250W and treatment time of 9.8min. Decay incidence and quality parameters of strawberries treated at the determined optimum conditions were compared with a water treatment during storage for 8d at 5°C. An ultrasonic treatment was found to be effective in inhibiting decay incidence and preserving quality in strawberries, and these results suggest that such a treatment may provide an alternative for extending shelf-life and maintaining quality of strawberry fruit. [Copyright &y& Elsevier]

The effect of methyl jasmonate (MeJA) on reducing anthracnose rot caused by Colletotrichum acutatum infection in postharvest loquat fruit (Eriobotrya japonica L. cv. Jiefangzhong) and the possible mechanisms involved were investigated. Freshly harvested loquat fruit were treated with 10μmol/L MeJA at 20°C for 24h. Both the treated and the untreated fruit were artificially wounded and inoculated with Colletotrichum acutatum spore suspension (1.0×105 spores/mL) 1 day after the treatment, and then incubated at 20°C for 6 days. Treatment of loquat fruit with MeJA resulted in significantly lower disease incidence and smaller lesion diameters than in control fruit. MeJA treatment significantly inhibited activities of catalase (CAT) and ascorbate peroxidase (APX) while superoxide dismutase (SOD) activity was not significantly affected in early infection, thus resulting in a higher level of H2O2 in the earlier period of incubation. The enhanced H2O2 generation by MeJA treatment might serve as a signal to induce resistance against C. acutatum infection. However, MeJA treatment inhibited the increase in phenylalanine ammonia-lyase (PAL), polyphenoloxidase (PPO) and peroxidase (POD) activities and lignin content, indicating that lignification is not the major defense mechanism against anthracnose rot in loquat fruit. The in vitro experiment showed that MeJA significantly inhibited spore germination, germ tube elongation and mycelial growth of C. acutatum. These results suggest that MeJA treatment can effectively inhibit anthracnose rot caused by C. acutatum in postharvest loquat fruit. It is postulated that the control of the disease is directly because of the inhibitory effect of MeJA on pathogen growth, and indirectly because of the induced disease resistance triggered by enhanced H2O2 levels. [Copyright &y& Elsevier]

The beneficial effects of γ-aminobutyric acid (GABA) on oxidative damage and programmed cell death (PCD) in fresh-cut pumpkins were preliminarily demonstrated in our previous research. However, the mechanism by which GABA alleviates PCD in fresh-cut pumpkins remains unclear. In this study, we discovered that GABA treatment effectively reduced mitochondrial structural damage and membrane permeability while increasing the mitochondrial membrane potential (ΔΨm) in fresh-cut pumpkins compared to the control. Additionally, GABA-treated pumpkins exhibited higher adenosine triphosphate (ATP) content and energy charge, consistent with increased activity of H+-ATPase, succinate dehydrogenase (SDH), malate dehydrogenase (MDH), and cytochrome c oxidase (COX). Conversely, the activity of alternative oxidase (AOX), Ca2+-ATPase, and K+-ATPase was reduced in GABA-treated pumpkins compared to the control. Moreover, key factors in apoptosis, such as the activity of six caspases and the gene expression of apoptosis-inducing factors (CmAIFs) and metacaspases (CmMCAs), were significantly decreased following GABA treatment. In conclusion, GABA effectively suppressed PCD in postharvest fresh-cut pumpkins by improving mitochondrial physiological properties and energy metabolism while inhibiting apoptosis-related factors. [Display omitted] ● GABA maintained normal ΔΨm, MPTP and ultrastructure of mitochondria. ● GABA increased energy charge by enhancing TCA cycle and electron transport chain. ● GABA decreased the activity and gene expression of apoptosis factors to inhibit PCD. [ABSTRACT FROM AUTHOR]

• Exogenous melatonin markedly extended the shelf life of broccoli. • Melatonin delayed the decline of chlorophyll content and chloroplast breakdown. • Melatonin regulated activities and gene expressions of chlorophyll catabolic enzymes. • Melatonin regulated the expressions of BoSGR1 and BoSGR2. The effect of melatonin treatment on color, chlorophyll degradation and chloroplast structure in broccoli during storage was evaluated. One hundred μmmol L−1 melatonin markedly extended the shelf life of broccoli. Compared with control florets, melatonin treatment delayed the decline of chlorophyll content, and maintained more intact chloroplasts. Meanwhile, melatonin also suppressed the activities of chlorophyll catabolic enzymes such as chlorophyllase (CLH), pheophytinase (PPH), pheophorbide a oxygenase (PAO) and red chlorophyll catabolite reductase (RCCR), and down-regulated the expressions of BoNYC1 , BoNOL , BoCLH , BoPPH , BoPAO , BoRCCR and BoSGR1 involved in chlorophyll catabolism. Taken together, our results indicated that melatonin could be a good candidate for delaying yellowing in broccoli during storage at 20 ℃. [ABSTRACT FROM AUTHOR]

• Water loss and chilling injury were alleviated by HRH storage in zucchini fruit. • HRH storage promoted the accumulation of proline and ABA under chilling stress. • HRH storage regulated polyamine metabolism in zucchini fruit. • HRH storage improved chilling tolerance of zucchini fruit by reducing water loss. In order to investigate the effect of water loss on the different physiological metabolism of zucchini fruit under cold stress after harvest, two cold rooms (4 ℃) with different relative humidities (RH: 74 ± 2 % and 98 ± 2 %) were used for cold storage. The result suggested that high relative humidity (HRH) storage slowed down the increase of weight loss, chilling injury index, malondialdehyde (MDA) content and cell death rate and maintained the postharvest quality such as firmness and flesh color in zucchini fruit. HRH storage promoted the accumulation of proline and induced higher ornithine δ-aminotransferase (OAT), Δ-1-pyrroline-5-carboxylate synthetase (P5CS) enzyme activities and lower proline dehydrogenase (PDH) enzyme activity as compared with low relative humidity (LRH) storage. The content of putrescine (Put) accumulated with the progress of cold damage, which could be delayed by HRH storage due to higher activities of polyamine oxidase (PAO), diamine oxidase (DAO) and ornithine decarboxylase (ODC). Besides, chilling stress induced the biosynthesis of abscisic acid (ABA) during storage and the zucchini fruit stored in high RH with less water loss showed more accumulation of ABA and higher activity of abscisic acid aldehyde oxidase (AAO) compared to zucchini fruit stored in low RH with severe dehydration during long-term cold storage. Taken together, our results suggested that the high RH storage could reduce water loss and alleviate chilling injury in zucchini fruit after harvest by promoting the accumulation of ABA and proline. [ABSTRACT FROM AUTHOR]

Abstract: This study investigated the regulation of ascorbate acid (AsA) and glutathione metabolism and chilling tolerance by methyl jamonate (MeJA) in loquat fruit. The results showed that application of MeJA to loquat fruit inhibited the incidence of chilling injury manifested as internal browning (IB) and increased AsA and reduced glutathione (GSH) contents due to the inhibition of ascorbate oxidase activity and enhancement of monodehydroascorbate reductase, dehydroascorbate reductase and glutathione reductase activities. Meanwhile, MeJA also enhanced activities of ascorbate peroxidase, glutathione peroxidase and glutathione-S-transferase. Our results suggested that MeJA can regulate the ascorbate and glutathione metabolism and has important roles in alleviating oxidative damage and enhancing chilling tolerance in loquat fruit. [ABSTRACT FROM AUTHOR]

• Broccoli senescence occurred with PCD and sucrose delayed the PCD process. • Sucrose inhibited DNA degradation and delayed the early apoptosis of broccoli cell; • Caspase-like activities in broccoli cells were suppressed under sucrose treatment. The effect of sucrose treatment on morphological and biochemical features of programmed cell death (PCD) in broccoli florets was explored. The apoptosis of untreated and treated cells was evaluated by flow cytometry (FCM) and by laser scanning confocal microscopy (LSCM). DNA ladders, resulting from the cleavage of nuclear DNA into oligonucleosomal fragments in PCD, were evaluated by gel electrophoresis. DNA frag-mentation and nuclear DNA condensation were further confirmed by using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end in situ labeling (TUNEL). The results revealed that sucrose treatment inhibited DNA degradation, and delayed the early apoptosis of broccoli cell as demonstrated with FCM and LSCM. DNA laddering was observed in control broccoli florets, which could not be detected in sucrose-treated samples. In addition, the caspase-like activities in broccoli cells were suppressed under sucrose treatment. Taken together, our results suggested that PCD was delayed in sucrose-treated broccoli florets, which provided a new model to investigate the mechanism of sugar in regulating PCD during postharvest storage. [ABSTRACT FROM AUTHOR]

• Sucrose treatment retarded the onset of PCD in broccoli florets. • Sucrose significantly retarded the cytochrome c release from mitochondria. • Sucrose improved the mitochondrial physiological properties. The effect of sucrose treatment on mitochondrial membrane potential (ΔΨm), contents of reactive oxygen species (ROS), cytochrome c oxidase (COX) activity, alternative oxidase (AOX) activity, mitochondrial Ca2+ content and cytochrome c release from mitochondria in broccoli florets during storage at 20 °C was investigated. The results showed that sucrose treatment effectively retarded the onset of programmed cell death (PCD) in broccoli florets by a mitochondria-dependent pathway. Sucrose treatment inhibited the increase of ROS and a decrease in ΔΨm, which was associated with the open state of permeability transition pore (PTP) and the ratio of cytochrome c/a. The decrease of COX activity and Ca2+ content in broccoli florets was suppressed under sucrose treatment. Sucrose treatment maintained higher AOX activity, and retarded the cytochrome c release from mitochondria. These results indicated that sucrose treatment delayed the appearance of PCD in broccoli florets through improving mitochondrial physiological properties. [ABSTRACT FROM AUTHOR]

Plant senescence is the final period of the plant life cycle and represents a programmed cell death (PCD) process. Melatonin, a versatile signaling molecule, exhibits potent free radical scavenging properties and actively participates in cellular antioxidant systems, effectively retarding plant senescence throughout its development. In order to illustrate the impact of melatonin on PCD during senescence, we examined the effects of exogenous melatonin at 80 μmol L−1 on PCD and mitochondrial function in broccoli bud cells at 25 ℃. The findings revealed that melatonin treatment not only maintained the morphological integrity of chloroplasts and mitochondria but also attenuated the decline in chlorophyll content by reducing the expression of genes that metabolize chlorophyll, including BoPPH , BoPAO , and BoSGR1. In comparison to the control group, the treatment decreased the content of H 2 O 2 and the rate of O 2 - production in mitochondria and simultaneously enhanced the activities of ascorbate peroxidase (APX), catalase (CAT), and superoxide dismutase (SOD), resulting in effective maintenance of reactive oxygen species (ROS) homeostasis and reduction of the level of lipid peroxidation in broccoli buds during senescence. Meanwhile, exogenous melatonin treatment up-regulated alternative oxidase (AOX) activity and its gene expression while delayed the reduction of cytochrome oxidase (COX) activity and restrained the over-opening of mitochondrial permeability transition pores (MPTP). Additionally, exogenous melatonin decelerated the increase in membrane potential and prevented mitochondria from releasing excess cytochrome c (Cyt c) into the cytoplasm. Taken together, the results indicate that melatonin treatment delayed mitochondrial dysfunction, preserved mitochondrial ROS homeostasis, and consequently postponed the initiation of PCD, ultimately inhibiting senescence in broccoli. ● Exogenous melatonin protects the structural of chloroplasts and mitochondrial. ● Exogenous melatonin down-regulates the chlorophyll degrading gene. ● Exogenous melatonin reduces mitochondrial dysfunction in broccoli. ● Exogenous melatonin delays the decline of APX, CAT and SOD activities. ● Exogenous melatonin delays the occurrence of programmed cell death in broccoli. [ABSTRACT FROM AUTHOR]

Highlights • CaCl 2 treatment stimulated a rapid accumulation of GABA in shredded carrots. • A dramatic increase in GABA content was observed in AsA-treated shredded carrots. • GABA accumulated through activating GABA shunt and polyamines degradation pathway. Abstract CaCl 2 or AsA treatment was applied to shredded carrots to explore their influences on GABA content and its metabolic pathway. The metabolites, enzyme activity and gene expression associated with GABA shunt pathway and polyamine degradation were measured. Results demonstrated that treatment with exogenous CaCl 2 or AsA alone not only significantly promoted the activities of glutamate decarboxylase (GAD), GABA transaminase (GABA-T), diamine oxidase (DAO), polyamine oxidase (PAO) and aminoaldehyde dehydrogenase (AMADH), but up-regulated the expressions of DcGAD 1, DcGAD 2, DcGABA-T 1 and DcPAO. Meanwhile, glutamate (Glu) content, a substrate for GABA shunt, was significantly reduced in both two exogenous treatments. In addition, lower putrescine (Put) and spermine (Spm) contents were observed in AsA treatment only. Taken together, our results suggested that both CaCl 2 and AsA treatments could activate GABA shunt pathway and polyamine degradation. CaCl 2 seemed to be more effective to GABA shunt regulation, while AsA to polyamine degradation. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate the effects of benzo-thiadiazole-7-carbothioic acid S -methyl ester (BTH) treatments on disease resistance against Botrytis cinerea infection and soluble sugar accumulation in grape berries and to analyze the possible cellular mechanisms involved. In grape berries, the results indicated that BTH treatments at 0.1 or 1 mmol L −1 could effectively inhibit B. cinerea infection possibly by directly inhibiting pathogen growth and indirectly inducing disease resistance. However, an obvious change in the composition of the soluble sugars was simultaneously observed in the BTH-treated berries. In parallel, addition of BTH at 0.1 or 1 mmol L −1 to the medium could effectively trigger a SAR defense response in grape suspension cells, and the defense included a cellular H 2 O 2 burst, VvNPR1.1 and PR1 genes expression, and the accumulation of stilbene phytoalexins. The 0.1 or 1 mmol L −1 BTH treatment induced higher activity of sucrose-hydrolyzing enzyme SS-cleavage and lower activities of sucrose-synthesizing enzymes such as SS-synthesis, SPS and SPP than the controls, contributing to the gradual increase in sucrose hydrolysis, a decrease in the glucose content and the accumulation of fructose in grape cells. Therefore, our results suggest that BTH exerts its effect on reducing fruit decay perhaps through the cellular SAR response. Moreover, the presence of costs in terms of altered soluble sugar components in grape berries may be attributed in changing activities of cellular sucrose-metabolizing enzymes after effective BTH elicitations. [ABSTRACT FROM AUTHOR]

The changes in chlorophyll, solanine, and plant hormones during greening in postharvest potatoes exposed to light were investigated. The results showed that as potatoes under light turned green, the contents of chlorophyll and solanine sharply increased due to the upregulation of genes involved in their biosynthesis. At the end of storage, the chlorophyll and solanine content in potatoes stored under light were approximately 25.44 times and 1.62 times higher, respectively, compared to those stored in the dark. Light exposure inhibited the accumulation of indole-3-acetic acid (IAA) and gibberellin in potatoes, which was associated with the downregulation of their anabolic genes and the positive regulation of their catabolic genes. In contrast, light treatment increased the levels of ethylene, melatonin, brassinosteroid, abscisic acid and 6-benzylaminopurine compared to dark-stored potatoes. Correlation analysis revealed that solanine content was negatively correlated with IAA (r = −0.93) during greening, while chlorophyll content was positively associated with ethylene production (r = 0.91) but negatively related to IAA (r = −0.89). Our results suggested potential roles of phytohormones in regulating chlorophyll and solanine during greening in light exposed potatoes, which deserves further investigation. • Light promoted chlorophyll and solanine metabolism in potatoes. • Light upregulated the biosynthesis of ethylene, MT, BR, ABA, and 6-BA. • Light reduced IAA and GA levels by regulating their metabolic gene expression. • Solanine content showed a negative correlation with IAA during greening. • Chlorophyll level correlated directly with ethylene but inversely with 6-BA and IAA. [ABSTRACT FROM AUTHOR]

Flesh softening is closely related to the quality of postharvest produces. Although the use of calcium chloride (CaCl 2) has been shown to inhibit fruit softening, the underlying molecular mechanisms have remained unclear. In our present investigation, CaCl 2 treatment resulted in an enhancement of cytosolic free Ca2+ and polysaccharide contents, firmness, and the integrity of the cell wall structure, particularly evident in the denser middle lamella of fresh-cut cantaloupe. CaCl 2 treatment also inhibited the cell wall degrading enzyme activities and gene expressions. Moreover, CmCAMTA2 could identify and bind to the CG-box structure of CmCellulase , Cmα-Gal3 , and Cmβ-Glu12 , thereby suppressing their transcription. In conclusion, current findings illustrated that CaCl 2 treatment triggered CmCAMTA2-mediated transcriptional suppression on cell wall degrading genes, inhibited the polysaccharide component degradation, and maintained better structure integrity of the cell wall, thereby delaying the flesh softening of fresh-cut cantaloupe. • CaCl 2 application delayed flesh softening of fresh-cut cantaloupe. • CaCl 2 maintained the structure integrity of cell wall in fresh-cut cantaloupe. • CaCl 2 lessened the polysaccharide component degradation of fresh-cut cantaloupe. • CaCl 2 treatment stimulated Ca2+ accumulation and the expression of CmCAMTA2. • Cell wall degradation was negatively modulated by Ca2+-CAMTA2 signal pathway. [ABSTRACT FROM AUTHOR]

Whitening and microbial infection are two major reasons to induce quality deterioration in fresh-cut carrots. Calcium chloride (CaCl 2) could enhance the quality attributes in fresh-cut carrots, but the molecular mechanism is still not illuminated. In this study, CaCl 2 treatment suppressed the increases of whiteness index and total bacterial count as well as enhanced the antioxidant capacity of fresh-cut carrots. In addition, CaCl 2 treatment promoted phenolics accumulation by upregulating the transcripts and enzyme activity of phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H) and 4-coumarate coenzyme A ligase (4CL) in phenylpropanoid pathway. However, this treatment inhibited the increase of enzyme activity and gene expression of cinnamyl alcohol dehydrogenase (CAD), thus suppressing lignin synthesis and whitening process in fresh-cut carrots. Moreover, a calmodulin-binding transcription activator (CAMTA) transcription factor DcCAMTA3, was induced in response to CaCl 2 treatment. DcCAMTA3 activated the transcription of DcPAL1 , DcC4H and Dc4CL1 genes and repressed the expression of DcCAD1 gene by directly targeting the CG-box. DcCML3/11, a calmodulin-like protein, interacted with DcCAMTA3, and this interaction enhanced DcCAMTA3-mediated transcriptional activation of DcPAL1 , DcC4H and Dc4CL1 and repression of DcCAD1. Therefore, CaCl 2 treatment is effective in maintaining quality and enhancing antioxidant capacity of fresh-cut carrots by the cooperative action of DcCMLs and DcCAMTA3 in positively regulating phenylpropanoid pathway. [Display omitted] ● Exogenous CaCl 2 enhanced the antioxidant capacity of fresh-cut carrots. ● CaCl 2 treated-fresh-cut carrots showed higher phenolic compounds content. ● CaCl 2 application delayed the whitening process in fresh-cut carrots. ● DcCML3 and DcCML11 protein physically interacted with DcCAMTA3. ● Phenylpropanoid metabolism modulated by CMLs-CAMTA3 signal transduction pathway. [ABSTRACT FROM AUTHOR]

• CaCl 2 treatment stimulated a rapid accumulation of GABA in fresh-cut pears. • LaCl 3 reduced GABA by inhibition of GABA shunt and polyamine degradation pathway. • CaCl 2 increased GABA content via GABA shunt rather than polyamine degradation. Effect of calcium chloride (CaCl 2) on γ-aminobutyric acid (GABA) accumulation pathways in fresh-cut pears was investigated. The metabolites, enzyme activity and gene expression associated with GABA shunt and polyamine degradation were measured. Results demonstrated that CaCl 2 treatment promoted GABA accumulation and reduced the glutamate (Glu) content in fresh-cut pears. Ca2+ fluorescence in pear cell, glutamate decarboxylase (GAD) activity and its gene expression increased significantly under CaCl 2 treatment correspondingly. Meanwhile, the Ca2+ channel blockers lanthanum chloride (LaCl 3) treatment not only significantly inhibited the activities of GAD, GABA transaminase (GABA-T), diamine oxidase (DAO), polyamine oxidase (PAO) and aminoaldehyde dehydrogenase (AMADH), but also down-regulated the transcripts of PbGAD , PbGABA-T , PbPAO1 and PbPAO2. Taken together, it can be concluded that CaCl 2 seems to be more effective to GABA shunt, while LaCl 3 treatment mightily stimulate GABA shunt and polyamine degradation pathway. [ABSTRACT FROM AUTHOR]

Chilling injury (CI) often occurs in postharvest peach fruit during low-temperature storage, and exogenous melatonin (MT) treatment has been demonstrated to alleviate CI in cold-stored peach fruit. In this study, we further investigated the effect of MT treatment on DNA methylation in relation to the chilling-induced browning in cold stored peaches. The results revealed that MT treatment upregulated PpPAL expression while simultaneously suppressing the transcripts of PpPPO and PpPOD. This dual effect resulted in the increased accumulation of phenolics, effectively reducing the incidence of browning in peaches stored at 4 °C. In addition, MT treatment increased the activities of methylesterase and demethylase, affecting significant changes in the DNA methylation levels of the local genes PpPPO , PpPOD and PpPAL , which suggested that MT treatment could mediate DNA methylation of the browning-related genes such as PpPPO , PpPOD and PpPAL , and consequently increased the phenolic contents and alleviated browning symptoms in cold-stored peaches. • MT treatment reduced chilling-induced browning in peaches. • MT increased the accumulation of phenolics in peaches. • MT upregulated PpPAL expression while suppressed the transcripts of PpPPO and PpPOD. • MT treatment increased the activities of methylesterase and demethylase. • MT regulated the DNA methylation levels of the local genes PpPPO , PpPOD and PpPAL. [ABSTRACT FROM AUTHOR]

Phenolics are secondary metabolites in plants. Calcium chloride (CaCl 2) application could promote phenolics accumulation whereas the molecular mechanism remains uncertain. In this study, CaCl 2 treatment reinforced the increase of individual phenolic acid content, PAL, C4H and 4CL activities and activated related expressions of CmPAL1 , CmPAL2 , CmPAL3 , CmC4H1 , CmC4H2 , CmC4H3 , Cm4CL1 and Cm4CL2 in fresh-cut cantaloupe. The total phenolics, total flavonoids content and antioxidant capacity in CaCl 2 -treated fresh-cut cantaloupe were 39.53%, 33.33% and 23.08% higher than those in control fruit after 24 h of storage, respectively. In the meantime, CaCl 2 application elevated of H+-ATPase, Ca2+-ATPase, SDH, CCO activities and elicited the transcription of CmH + -ATPase4 , CmCa 2+ -ATPase2 , CmSDH5 and CmCCO6 genes in fresh-cut cantaloupe. Moreover, CmCAMTA4, an up-regulated calmodulin-binding transcription activator (CAMTA) induced by CaCl 2 was identified in fresh-cut cantaloupe. Further study suggested that CmCAMTA4 could bind the CG-box in the promoter region of CmPAL3 , Cm4CL1 and CmCCO6 to activate their transcription. In summary, these findings indicated that CaCl 2 treatment could activate the transcription of CmPAL3 , Cm4CL1 and CmCCO6 mediated by CmCAMTA4, which stimulated the phenylpropane pathway and maintained higher energy status, thus facilitating the biosynthesis of phenolics in fresh-cut cantaloupe during storage. • CaCl 2 treatment could enhance antioxidant capacity, phenolics and flavonoids contents of fresh-cut cantaloupe. • CaCl 2 treatment activated phenylpropane pathway and energy metabolism of fresh-cut cantaloupe. • CaCl 2 treatment up-regulated the expression of CmCAMTA4. • Phenolics accumulation was positively modulated by Ca2+-CAMTA4 signal transduction pathway. [ABSTRACT FROM AUTHOR]

The effects of indoleacetic acid (IAA) treatment on chilling injury and endogenous phytohormones in peach fruit were studied. The results showed that IAA treatment decreased chilling injury index of cold-stored peaches, effectively maintaining fruit firmness and reducing the electrical conductivity level. IAA treatment upregulated the expression of IAA biosynthetic gene PpMES and signaling pathway gene PpSAUR , but reduced the transcript abundance of IAA degradative genes PpDAO , PpGH3 , and PpIAMT , leading to endogenous IAA accumulation in treated peaches. Meanwhile, after IAA treatment, contents of melatonin and γ-aminobutyric acid (GABA) were also increased which was associated with the upregulation of their anabolic genes and downregulation in GABA catabolic genes. In addition, the levels of abscisic acid (ABA) and gibberellin (GA) were reduced in treated peaches due to its modification in the transcript levels of ABA and GA metabolic genes. Collectively, IAA could alleviate the symptoms of chilling injury in peach fruit via regulating contents of endogenous phytohomones such as IAA, melatonin, GABA and GA. • IAA treatment reduced chilling injury and maintain fruit quality in peaches. • IAA induced endogenous IAA content in harvested peaches. • IAA increased melatonin and GABA contents in harvested peaches. • IAA inhibited ABA and GA contents in harvested peaches. [ABSTRACT FROM AUTHOR]

The potential regulatory mechanisms of 1 % calcium chloride (CaCl 2) treatment on the γ-aminobutyric acid (GABA) accumulation of fresh-cut carrots were investigated. The results indicated that CaCl 2 application enhanced the contents of GABA shunt-related substances and activated the GABA shunt via enhancing the activities and genes expression of glutamate decarboxylase (GAD) and GABA transaminase (GABA-T). Moreover, CaCl 2 treatment enhanced the levels of [Ca2+] cyt , as well as up-regulated the expression of DcCaM7 and DcCAMTA6. However, the EGTA, a Ca2+ chelating agent treatment had the opposite effect on both GABA shunt and calcium signal-related components. Importantly, DcCaM7 interacted with DcCAMTA6 through an IQ motif, forming a heterodimer that facilitated the enhanced transcriptional regulation of DcCAMTA6 in the expression of DcGAD and DcGABA-T genes. Therefore, our results indicated that DcCaM7-DcCAMTA6 complex positively regulate GABA accumulation by activating GABA shunt in fresh-cut carrots. • CaCl2 treated-shredded carrots maintained higher GABA and glutamate content. • CaCl2 treatment activated GABA shunt and calcium signal of fresh-cut carrots. • CaCl2 promoted the expression of DcCaM7 and DcCAMTA6. • DcCaM7 protein physically interacted with DcGAD/DcCAMTA6. • GABA shunt modulated by Ca2 + -CaM7-CAMTA6 signal transduction pathway. [ABSTRACT FROM AUTHOR]

Conserved pathogen-derived features of microbial invaders are sensed by plants via pattern-recognition receptors (PRRs) and induce both local and systemic immune responses. The plant PRR flagellin sensitive 2 (FLS2), a leucine-rich repeat-receptor kinase, recognizes pathogen-derived molecules and initiates pattern-triggered immunity (PTI) responses by associating with other potential kinases to propagate downstream signalling cascades. Here, we identified a plasma membrane-localized receptor-like kinase BAK1 from strawberry (FvBAK1) that is rapidly induced upon exposure to the plant-specific hormone brassinosteroid (BR), which provides strawberry fruit with immunity to the necrotrophic fungus Botrytis cinerea. FvBAK1 reciprocally interacts with FvFLS2 and the receptor-like cytoplasmic kinase FvBIK1 in yeast cells in vivo. Subsequently, FvBIK1 can directly interact with respiratory burst oxidase homologue D (FvRBOHD), contributing to FvRBOHD-dependent ROS accumulation to amplify the SA signalling pathway in the BR-stimulated immunity of postharvest strawberry fruit to B. cinerea infection. Importantly, overexpression of bak1 promotes ROS accumulation and BR-induced defence responses, whereas bak1 loss-of-function mutants have compromised BR-induced SA signalling and immunity to necrotrophic fungal pathogens. In such a situation, FvBAK1 is an essential component of BR-mediated PTI signalling, which links the pathogen-derived receptor complex to downstream intracellular signalling pathways. Taken together, the findings of the current study highlight the importance of FvBAK1 as an upstream regulator of FvBIK1 and as a coreceptor of FvFLS2 in establishing BR-induced PTI signalling in postharvest strawberry fruit. • 10 μM BR exhibited a decrease in disease incidence in postharvest strawberries. • FvBAK1 was induced in postharvest strawberries when treated with BR. • FvBAK1 was an essential component of BR-mediated PTI signalling. • FvBAK1 worked as an upstream regulator of FvBIK1. • FvBAK1 was a coreceptor of FvFLS2 in establishing BR-induced PTI signalling. [ABSTRACT FROM AUTHOR]

Glutathione (GSH) improves the scavenging capacity of reactive oxygen species (ROS) in postharvest fruit and vegetable, but the effect of exogenous GSH in okra (Abelmoschus esculentus) has not been clarified. This study investigated the effect of GSH on ROS scavenging in postharvest okra and found that GSH treatment effectively inhibited weight loss and alleviated browning and thereby maintained the appearance and quality of the fruit. Moreover, GSH suppressed levels of hydrogen peroxide (H 2 O 2), superoxide radical (O 2 -), and malondialdehyde (MDA). Treatment with exogenous GSH increased the contents of ascorbic acid (AsA) and GSH in okra, while decreased the contents of dehydroascorbic acid (DHA) and oxidized glutathione (GSSG). GSH treatment also enhanced the ROS-scavenging ability of okra by upregulating the expression of AeAPXs , AeGRs , AeMDHARs and AeDHARs , all of which are associated with redox homeostasis. Collectively, our findings demonstrate that exogenous GSH treatment can extend the shelf life of okra by mediating redox homeostasis. • Exogenous GSH could effectively maintain the quality of okra. • Exogenous GSH could maintain redox homeostasis during okra storage. • GSH enhanced the ROS-scavenging ability by altering related genes expression. • GSH enhanced the activity of the AsA-GSH cycling enzymes. [ABSTRACT FROM AUTHOR]

Degreening or yellowing caused by rapid chlorophyll (Chl) degradation is a characteristic event during maturation or senescence in green plant organs. In our present study, the effect of gibberellic acid (GA) treatment on Chl content and shelf life in postharvest okras was investigated. Our results indicated that GA treatment could postpone fruit senescence and Chl degradation in okras during storage. Meanwhile, GA treatment also down-regulated the expressions of genes such as AeNYC , AeNOL , AeSGR , AePAO , AeCLH , AeRCCR , AePPH and AeHCAR involved in Chl degradation. Moreover, the down-regulation of transcript abundances of four candidate ERF transcription factors (TFs), preliminarily screened from the okra transcriptome database, was also observed in GA-treated okras. In conclusion, GA had a positive effect on maintaining chlorophyll content and fruit quality of okras after harvest, due to its negative regulation on Chl degradation genes and probably the candidate ERF TFs. • GA-treated okras maintained higher chlorophyll contents during storage. • GA treatment down-regulated the expression of chlorophyll catabolic genes. • The ERF TFs may be involved in chlorophyll degradation. [ABSTRACT FROM AUTHOR]

• 1-MCP treatment maintained higher contents of AsA and T-AsA in kiwifruit. • 1-MCP treatment promoted the expression levels of genes in AsA metabolic pathway. • The bHLH TFs may be involved in regulating AsA accumulation by 1-MCP treatment. This research was conducted to investigate the mechanism of 1-methylcyclopropene (1-MCP) treatment on ascorbic acid (AsA) content in kiwifruit after harvest. Our findings indicated that 1-MCP treatment postponed the course of fruit senescence and maintained higher contents of AsA and total ascorbic acid (T-AsA) during storage in postharvest kiwifruit. Gene expression analysis revealed that the transcription level of genes involved in AsA metabolic pathway were regulated by 1-MCP treatment. The up-regulation of genes for AsA biosynthesis (AdGME , AdGalDH , AdGalLDH and AdGalUR) and regeneration (AdDHAR and AdGR) and down-regulation of degradation genes (AdAO) collectively contributed to the increase in AsA level in treated kiwifruit during storage. Moreover, the expression level of four candidate bHLH transcription factors, preliminarily screened from the transcriptome database of kiwifruit, was up-regulated by 1-MCP treatment by qPCR analysis. Taken together, our results suggested that due to its positive regulation on numerous ascorbate modifying genes and probably the candidate bHLH transcription factors, 1-MCP had a beneficial effect on AsA content. [ABSTRACT FROM AUTHOR]