LeMAPK4 participated in cold‐induced ethylene production in tomato fruit

BACKGROUND: Mitogen‐activated protein kinase (MAPK, EC 2.7.11.24) cascade from several plant species has been shown to be activated during response to abiotic stress. Ethylene plays an important role in fruit tolerance to environmental stress. However, the mechanisms by which MAPK regulates defence systems in fruit and the relationship between MAPK and ethylene remain to be determined. RESULTS: MAPK inhibitor significantly decreased the chilling tolerance of tomato (Lycopersicon esculentum cv. Lichun) fruit during cold storage. Moreover, decreases in ethylene content, LeACS2 expression and activities of 1‐aminocyclopropane‐1‐carboxylic acid (ACC) synthase (ACS, EC 4.4.1.14) and ACC oxidase (ACO, EC 1.14.17.4) due to MAPK inhibitor occurred within 24 h after cold treatment. Upon treatment with cold and ethephon, the ethylene content, activities of ACS and ACO and expression of LeACS2, LeACO1 and LeMAPK4 increased. CONCLUSION: The results showed the regulation of MAPK in ethylene biosynthesis to protect tomato fruit from cold stress. In addition, the participation of LeMAPK4 in cold‐induced ethylene biosynthesis in tomato fruit was indicated. © 2013 Society of Chemical Industry     

Methyl jasmonate alleviates the reduced release of aroma-related esters in ‘Nanguo’ pears by regulating ethylene biosynthesis and signal transduction

Cryopreserved fruits usually develop symptoms, which affects the release of aroma. Our study investigated the impact of exogenous methyl jasmonate (MeJA) upon the synthesis of aromatic esters in ‘Nanguo’ pears after cold storage. It found that exogenous MeJA enhanced ethylene accumulation via improving the activity of 1-aminocyclopropane-1-carboxylic-acid (ACC) synthase (ACS) and ACC oxidase (ACO) and the expression levels of PuACS1 and PuACO1. After cryopreservation for 90 days, the ester aroma of ‘Nanguo’ pears was effectively improved by MeJA during normal temperature shelf life. In addition, the expression of PuERS1, PuETR1, PuEIN4, PuEIN2 and PuERF1 in MeJA-treated fruits were obviously increased. Therefore, we infer that the influence of MeJA on production of aroma-related esters in ‘Nanguo’ pears is closely connected with ethylene biosynthesis and signal transduction, namely increase activity of ACS and ACO, and upregulation of the expression level of PuACS1, PuACO1, PuERS1, PuETR1, PuEIN2, PuEIN4 and PuERF1.     

Impact of exogenous salicylic acid treatment on the cell wall metabolism and ripening process in postharvest tomato fruit stored at ambient temperature

Tomato is a climacteric fruit susceptible to rapid softening and ripening after harvest. In this study, the changes of physicochemical characters, cell wall-degrading enzymes, cell wall compositions and ethylene production of ‘Hisar Arun’ and ‘BSS-488’ tomato fruits were investigated under the influence of salicylic acid treatment. Salicylic acid treatment effectively delayed firmness decline and increase in PLW, TSS and lycopene content. The treated fruits maintained the integrity of cell wall composition by delay in increase in activities of cell wall-degrading enzymes (pectin methylesterase, polygalacturonase and cellulose) and cell wall components (cellulose, hemicellulose, lignin and pectin) decline. Moreover, salicylic acid treatments significantly suppress expression level of ethylene-producing genes (ACO1 and ACS2) and inhibited ethylene production during storage. Overall, the salicylic acid-induced delay in the ripening process occurs via the strong inhibition of ethylene biosynthesis, lowered cell wall-degrading enzyme activities and slowed cell wall degradation.     

Effects of nitric oxide on the alleviation of postharvest disease induced by Penicillium italicum in navel orange fruits

The present study evaluated the effects of 15 μL L^-1 nitric oxide (NO) on the fruit defence response of ‘Newhall’ navel orange. The decay rate of NO-treated navel orange fruits was significantly lower than that of control fruits during storage at 20 °C storage (P < 0.05). Treatment with NO suppressed the increase in disease incidence and lesion area in orange fruits inoculated with Penicillium italicum (P. italicum); significantly increased the activities of phenolic metabolism-associated enzymes and pathogenesis-related (PR) proteins, including polyphenoloxidase (PPO), phenylalanine ammonia-lyase (PAL), β-1,3-glucanase (GLU) and chitinase (CHT); and enhanced the activities of key enzymes, including 4-coumarate: CoA ligase (4CL), cinnamate-4-hydroxylase (C4H) and chalcone isomerase (CHI) in the phenylpropanoid pathway. The contents of total phenolics, flavonoids and lignin were also higher in NO-treated fruits than in control fruits. The findings suggest that exogenous NO could induce disease resistance against P. italicum in navel orange fruits.     

The effects of 1-methylcyclopropene treatment on the shelf life and quality of cherry tomato (Lycopersicon esculentum var. cerasiforme) fruit

The use of 1‐methylcyclopropene (1‐MCP) to extend the shelf life of cherry tomato (Lycopersicon esculentum var. cerasiforme) was investigated. Higher concentrations of 1‐MCP delayed the ethylene induced climacteric peaks in mature green (MG) and breaker (BR) fruits. Thirteen days after treatment, control fruits were 55% as firm as fruit treated with 0.11 μL L^?1 1‐MCP. The initiation of fruit softening, chlorophyll degradation and accumulation of lycopene and carotenoids was delayed in treated fruits. Higher 1‐MCP concentrations inhibited the accumulation of lycopene and carotene such that the colour of the fruit did not reach that of control fruit. Treatment of MG cherry tomatoes with 1‐MCP enhanced shelf life optimally, while treatment of BR fruits was beneficial where full colour and high content of lycopene and carotenoids is important. Differentiation of the different stages of ripening before application of 1‐MCP is needed in order to succeed in accomplishing different postharvest objectives.     

Effect of 1-pentylcyclopropene on Physiological Responses and Gene Expression of Ethylene Receptors in Post-Harvest Bananas

The aim of this study was to investigate the inhibitory effect of 1-pentylcyclopropene (1-PentCP), a structural analogue of 1-methylcyclopropene (1-MCP), on postharvest ripening and senescence of bananas fruit (Musa acuminata L. AAA group cv. Brazil). The results showed that 1-PentCP was effective in postponing the occurrence time of ethylene production peak and respiration rate peak, delaying the softening and color change, inhibiting the increasing of soluble solids, soluble sugar, and 1-aminocyclopropane-1-carboxylate acid (ACC) content; inhibiting the activities of ACC synthase (ACS) and ACC oxidase (ACO); and suppressing the expression of MaERS1 and MaERF1 in bananas. In addition, 1.2 μL/L 1-PentCP was found to be most effective in delaying ripening and senescence process of bananas by inhibiting the activities of enzymes involved in ethylene biosynthesis and gene expression of ethylene receptors. It is suggested that 1-PentCP could be a promising candidates for practical use as a given ethylene inhibitor applied before the onset of ethylene action.     

Increased ethylene biosynthesis elevates incidence of chilling injury in cold‐stored ‘Amber Jewel’ Japanese plum (Prunus salicina Lindl.) during fruit ripening

Mature ‘Amber Jewel’ Japanese plum fruit were stored at 0 or 5 °C for 3 and 6 weeks to investigate their effects on ethylene (C₂H₄) biosynthesis during ripening at ambient temperature in the development of chilling injury (CI) and fruit quality. CI (internal breakdown and browning) and fruit softening were higher during ripening, in the fruit stored at 5 °C than 0 °C, irrespective of storage period (SP). C₂H₄ production and activities of 1‐aminocyclopropane‐1‐carboxylic acid synthase (ACS) and 1‐aminocyclopropane‐1‐carboxylic acid oxidase (ACO) enzymes, and 1‐aminocyclopropane‐1‐carboxylic acid (ACC) content were higher during ripening in fruit stored at 5 °C than 0 °C. The fruit stored at 5 °C also exhibited higher respiration rate and higher soluble solids concentration/titratable acidity ratio. In conclusion, increase in storage temperature and SP elevates the activities of ACS and ACO enzymes and consequently C₂H₄ production which leads to the development of CI in plum fruit with advancement of ripening.     

Effect of calcium and calmodulin antagonists on ethylene biosynthesis in tomato fruits

The aim of this work was to elucidate the mode of action of calcium in calcium-inhibited ethylene biosynthesis. In one experiment, mature green tomatoes were treated with 1·5% (w/v) CaCl₂+60 μM N-6(aminohexyl)-1-naphthalenesulphonamide (W5). 1·5% (w/v) CaCl₂+60 μM N-6(aminohexyl)-5-chloro-1-naphthalenesulphonamide (W7), 1·5% (w/v) CaCl₂ alone or distilled water (control). The control and the W7 treatment had much higher ethylene production than either the CaCl₂ treatment alone or the CaCl₂+W5 treatment. In another experiment, similar tomatoes were treated with 1·5% (w/v) CaCl₂+15 μM trifluoperazine (TFP). 1·5% (w/v) CaCl₂ only, or distilled water (control). The treatment with 1·5% CaCl₂+15 μM TFP gave higher ethylene production than 1·5% (w/v) CaCl₂ without TFP, and nearly the same level as the control towards the end of the experimental period. For enzyme and intermediate metabolite assays, mature green tomatoes were treated with 1·5% (w/v) CaCl₂ plus either W5 or W7. W5 treatment had a lower ethylene forming enzyme (EFE) activity, higher 1-aminocyclopropane-1-carboxylic acid (ACC) concentration, similar levels of ACC synthase activity and 1-(malonylamino)-cyclopropane-1-carboxylic acid concentration, compared to the control and W7 treatment. As W7 is a more potent calmodulin antagonist than W5, these results suggest a calcium-calmodulin inactivation of EFE activity. © 1998 SCI.     

Biochemical features and inhibitors of the 1-aminocyclopropane-1-carboxylic acid oxidase isolated from pear fruit

 1-Aminocyclopropane-1-carboxylic acid (ACC) oxidase, the enzyme that catalyzes the final step in ethylene biosynthesis, was recovered from pear (Pyrus communis L. cv. Blanquilla) fruit tissues with maximum activity at pH 6.5. The enzyme eluted as a single hydrophobic protein with an estimated molecular weight of 37.9 kDa in a three-step FPLC chromatographic procedure. The sensitivity of the pear ACC oxidase against a range of chemicals known by their inhibitory action on ethylene biosynthesis in vivo has been studied. Among them, and in contrast to a previous proposal, α-(p-chlorophenoxy)isobutyric acid, a substance possessing antiauxin properties, did not inhibit the in vitro enzyme activity. The significance of the results is discussed in terms of the nature and mechanism of the enzyme reaction. Received: 12 May 1999 / Revised version: 7 July 1999     

Effect of 1-methylcyclopropene on tomato flavour components, shelf life and decay as influenced by harvest maturity and storage temperature

BACKGROUND: In Florida, tomatoes are harvested green (GR), which includes mature green (MG) and immature green (IG) fruits, and stored at low temperature (13 °C), resulting in poor flavour. Flavour improvement might be achieved if fruits were harvested with some colour (to eliminate IG fruits) and/or stored at higher temperature with the ripening inhibitor 1‐methylcyclopropene (1‐MCP). RESULTS: ‘Florida 47’ tomatoes were harvested at GR (MG + IG), breaker (BR), turning (TR) and pink (PK) stages, treated (+) or not (?) with 1‐MCP and stored at 13 and/or 18 °C. 1‐MCP treatment resulted in a gain of up to 6 days of shelf life depending on harvest maturity and storage temperature. Storage at 18 °C rather than 13 °C resulted in an increase in internal red colour, soluble solids (SS)/titratable acidity (TA) ratio and levels of many volatiles studied. The shelf life of BR (+) MCP fruits stored at 13 °C was similar to that of MG fruits. IG fruits exhibited lowest levels of SS, TA and ten volatiles compared with BR fruits. CONCLUSION: Harvesting tomatoes with colour (BR), thereby eliminating IG fruits, and treating with 1‐MCP resulted in better quality with adequate shelf life. Published 2011 by John Wiley & Sons, Ltd.     

氯吡苯脲浸泡处理延缓采后芒果成熟和软化的生理机制

以采后‘贵妃’芒果为试材,使用10 mg/L氯吡苯脲（forchlorfenuron,CPPU）溶液对果实浸泡处理10 min,晾干后在室温（25 ℃）条件下贮藏8 d,研究CPPU浸泡处理对芒果果实贮藏期间成熟与软化相关生理指标的影响。结果显示：CPPU浸泡处理明显抑制了芒果果实的呼吸作用并推迟了果肉色泽、硬度、可溶性固形物质量分数和可滴定酸质量分数的变化;CPPU浸泡处理有效抑制了果实1-氨基环丙烷-1-羧酸合成酶和1-氨基环丙烷-1-羧酸氧化酶活性,导致乙烯释放量降低;此外,CPPU浸泡处理显著抑制了果实多聚半乳糖醛酸酶、果胶甲酯酶、β-半乳糖苷酶等果胶水解酶活性变化,并较大程度抑制了果胶多糖的增溶与解聚作用,故而延缓了果实的软化进程。结论：CPPU浸泡处理能有效延缓采后芒果果实的成熟与软化,从而延长果实货架寿命。     

脱落酸处理对苹果成熟、乙烯合成及其信号转导基因表达的影响

为研究脱落酸（abscisic acid,ABA）对苹果果实采后成熟、乙烯合成及其信号转导基因表达的影响,本实验以‘Granny Smith’苹果果实为实验材料,将其进行外源ABA处理后置于20 ℃贮藏（以无菌水处理为对照）,测定贮藏过程中的硬度、可滴定酸质量分数、纤维素酶活力、果胶甲酯酶活力、叶绿素含量、内源ABA含量、乙烯产生速率及乙烯生物合成基因（ACO1、ACO2、ACS1、ACS3）、苹果乙烯信号转导基因（ERS1、ERS2、ETR2、ERF3、ERF4、ERF5）的表达量。结果表明,与对照组相比,ABA处理能降低苹果果实贮藏过程中的硬度和可滴定酸质量分数,提高果实中的纤维素酶和果胶甲酯酶活性,促进叶绿素a、叶绿素b和总叶绿素含量降低。定量聚合酶链式反应分析结果表明,与对照组相比,ABA处理能够显著提高苹果乙烯生物合成基因的表达量（P＜0.05）。同时,参与苹果乙烯信号转导的ERS2、ETR2和ERF3、ERF4、ERF5表达量随着果实采后成熟明显增加,并且ABA处理组果实中的表达量总体显著高于对照组（P＜0.05）。综上,外源ABA处理能够促进苹果内源ABA的合成,提高苹果乙烯生物合基因和信号转导基因的表达,促进苹果内源乙烯合成和乙烯信号的转导,加快苹果果实的采后成熟进程。     

Physiological properties of fresh‐cut watermelon (Citrullus lanatus) in response to 1‐methylcyclopropene and post‐processing calcium application

Seedless watermelon (Citrullus lanatus Thunb. Mansfeld, cv. Millionaire) fruit were exposed to 10 µL L⁻¹ 1‐methylcyclopropene (1‐MCP) or air for 18 h. Afterward, the fruit were processed into placental‐tissue pieces, treated with calcium dips (20 g kg⁻¹ CaCl₂) or deionized water, and stored in vented containers for 7 days at 10 °C. At intervals during storage, fresh‐cut placental tissue was monitored for respiration, ethylene production, firmness, electrolyte leakage, total soluble solids, titratable acidity and microbial growth. Ethylene production was below detection in fresh‐cut placental tissue, consistent with the low ethylene production in intact watermelon fruit. Respiration rates were significantly enhanced in response to tissue processing, and continued to increase throughout the 7 days of storage. Tissue derived from 1‐MCP‐treated fruit showed enhanced 1‐aminocyclopropane‐1‐carboxylate synthase (ACS, EC 4.4.1.14) activity, suppressed respiratory rates and undetectable levels of 1‐aminocyclopropane‐1‐carboxylate oxidase (ACO) activity during storage. Post‐processing calcium dips (CaCl₂) had little influence on ACS activity relative to tissue not receiving calcium, but significantly enhanced ACO activity and maintained firmness of fresh‐cut tissue throughout storage. The data collectively support the conclusion that 1‐methylcyclopropene treatment of intact watermelon fruit is alone unlikely to benefit the storage duration of fresh‐cut watermelon. Copyright © 2005 Society of Chemical Industry     

Modified atmosphere packaging confers additional chilling tolerance on ethylene-inhibited cantaloupe Charentais melon fruit

Cantaloupe Charentais melon fruits are subject to chilling injury when stored at low temperatures, around 2 °C. Ethylene-suppressed cantaloupe Charentais melon, expressing a 1-aminocyclopropane-1-carboxylic acid (ACC)-oxidase gene in antisense orientation, showed strong, but not total, resistance to chilling injury, allowing an extended storage at low temperatures. Modified atmosphere packaging (MAP) is known to alleviate chilling injury symptoms in a variety of chilling-sensitive horticultural commodities. In the present work, we have compared the effects of MAP in non-retractile plastic film and storage in air on ethylene production, respiratory activity, development of chilling injury symptoms, water loss, ion leakage and accumulation of ethanol and acetaldehyde in wild-type and ethylene-suppressed melons, during storage at 2 °C and after re-warming at 22 °C. MAP reduced chilling injury and extended the postharvest life of wild-type fruit and conferred additional chilling resistance on ethylene-suppressed melons. Reduction of ethylene production and water loss are necessary to prevent chilling injury symptoms in melon.     

Ripening and ethylene biosynthesis in controlled atmosphere stored apricots

 Ethylene synthesis and metabolism were studied in apricot fruits (Prunus armeniaca L. cv. Búlida, under controlled atmosphere (CA) conditions (20% CO₂ and 20% O₂; 20% CO₂ and 1% O₂; 0.03% CO₂ and 1% O₂) and at a temperature of 2  °C. In control apricots stored outdoors in air containing 20% O₂ and 0.03% CO₂, the evolution of the physical and chemical parameters characteristic of ripening (loss of texture, decrease in acidity and increase in soluble solids) was slow during the storage period. However, for apricots stored in CAs containing 1% O₂ and 20% or 0.03% CO₂, these parameters did not show significant changes during the storage period. Ethylene production was completely inhibited in apricots stored in the three CAs, while control fruits showed a maximum ethylene level after 2 weeks of storage. This inhibition was accompanied by lower levels of 1-aminocyclopropane-1-carboxylic acid, free and total, which were more pronounced in apricots stored in the CAs containing 20% CO₂. In apricots stored in the CAs containing 1% O₂, the ethanol content increased after 1 week of storage, and this caused a smell and taste that made the fruits unsuitable for consumption. Received: 16 October 1998     

Inhibition of Oxidative and Antioxidative Enzymes by Trans-Resveratrol

ABSTRACT: Trans-resveratrol, a phytoalexin produced by a variety of plants, has been shown to inhibit oxidative enzymes in an animal cell system. Its effect on several oxidative and antioxidative enzymes from plants was investigated using in vitro assays. Trans-resveratrol inhibited superoxide dismutase, lipoxygenase, catalase, peroxidase, polyphenol oxidase, and 1-aminocyclopropane-1-carboxylic acid oxidase with apparent K_I's of 10, 90, 100, 255, 305, and 350 μM, respectively. Trans-resveratrol inhibited lipoxygenase activity more effectively than other lipoxygenase inhibitors, including propyl gallate, ibuprofen, ursolic acid, acetylsalicylic acid, and salicylhydroxamic acid.