1-methylcyclopropene Treatment Research Articles

Effect of 1-Methylcyclopropene and Chitosan Treatment on Biochemical and Antioxidant Properties of Avocado (Persea Americana Mill.) Fruit During Low and Ambient Temperature Storage

Effect of 1-Methylcyclopropene and Chitosan Treatment on Biochemical and Antioxidant Properties of Avocado (Persea Americana Mill.) Fruit During Low and Ambient Temperature Storage

Characterization of morphological and chemical changes using atomic force microscopy and metabolism assays: the relationship between surface wax and skin greasiness in apple fruit.

Skin greasiness occurred on stored apples (Malus domestica Borkh.) is generally believed to result from changes in surface wax components. Previous reports have typically correlated wax changes with greasiness scores to reveal the contributing wax components. A notable limitation of this approach is that greasiness scores are highly subjective and influenced by individual perception. This study aimed to assess skin quality by quantitatively analyzing wax morphology changes in greasy 'Jonagold' apples using Atomic Force Microscopy (AFM) roughness parameters Ra, Rq, Rmax, and Rz, and to correlate these changes with wax composition. AFM results revealed that wax crystals disappeared as skin greasiness increased, accompanied by significant declines in roughness parameters Ra, Rq, Rmax, and Rz, which decreased by 70% to 85%. Chemical analysis showed a significant increase in liquid esters, including linoleate and oleate esters, in the surface waxes, which negatively correlated with the decline in roughness parameters. Key genes related to ester production, such as MdFAD2, MdWSD1, and MdWBC11, exhibited increased expression and were also negatively correlated with decreases in Rq, Ra and Rz. Additionally, 1-Methylcyclopropene (1-MCP) treatment suppressed both the development of greasiness and the associated changes. Our findings suggest that the increased liquid esters contribute to alternations in wax morphology in greasy apples, and that MdFAD2, MdWSD1, and MdWBC11, play crucial roles in ester biosynthesis. These results highlight the effectiveness of AFM roughness parameters Ra, Rq, Rmax, and Rz in quantifying wax morphology changes in apples during skin greasiness development.

Transcriptome sequencing analysis of the effects of 1-MCP and ethephon treatments on the storage quality of Pleurotus pulmonarius

Pleurotus pulmonarius has gained a lot of popularity among consumers due to its exquisite flavor and several nutritional benefits. However, P. pulmonarius fruiting bodies are susceptible to deterioration in quality following harvest. To investigate the impact of 1-methylcyclopropene (1-MCP) and ethephon treatments on P. pulmonarius quality degradation, its antioxidant and sensory quality indices were assessed following treatment with 0.75μL/L 1-MCP and 0.05 % ethephon. Transcriptomic sequencing was performed on P. pulmonarius at different treatment time points. Based on the findings, 1-MCP treatment resulted in the maintenance of high firmness levels, increased glutathione content, and superoxide dismutase activity. At the same time, it lowered membrane permeability, slowed the rate of weight loss, reduced the levels of malondialdehyde, boosted antioxidant capacity, and resulted in improved storage quality. On the other hand, the ethephon treatment hastened the browning of P. pulmonarius by raising ethylene release, polyphenol oxidase activity, and b* value. Based on the transcriptome analysis, the number of differentially expressed genes (DEGs) on the 5th day was much higher than that on the 1st and 9th day of storage. Overall, 5422 DEGs were significantly enriched in the different treatment groups. Moreover, 62 DEGs exhibited significant differences between each treatment group and were mainly enriched in the pathways of 2-oxocarboxylic acid metabolism, glycerolipid metabolism, and biosynthesis of nucleotide sugars, which were closely related to the storage quality of P. pulmonarius. This study provides a theoretical basis for using 1-MCP for the storage and preservation of P. pulmonarius using 1-MCP, which has significant theoretical and practical implications.

1-Methylcyclopropene and Bacillus Treatment Affects Blueberry Storage Quality and Antioxidant Levels

Blueberries are rich in a variety of functional substances and have high nutritional and health values, but they are not resistant to decline during fresh storage. Here, the effects of six Bacillus species on the storage quality of, and antioxidant levels in, the southern highbush blueberry ‘O’Neal’ fruit were investigated. Bacillus treatments reduced the fruit decay rate, slowed fruit quality decline, inhibited malondialdehyde accumulation, and increased superoxide dismutase and peroxidase activity levels. Bacillus altitudinis Y-14 had the best effect overall. Furthermore, the effects of 1-methylcyclopropene (1-MCP), B. altitudinis Y-14, and 1-MCP + B. altitudinis Y-14 treatments on the storage quality and antioxidant of rabbiteye blueberry ‘Brightwell’ fruit were investigated, and each treatment effectively reduced the decay rate and weight loss of fruit. When stored for 25 days, the decay rate of the 1-MCP + B. altitudinis Y-14 group was only 8.33%, significantly lower than that of the control. The three treatments delayed the decline in fruit quality, inhibited malondialdehyde accumulation, and increased superoxide dismutase and peroxidase activity levels. The 1-MCP + B. altitudinis Y-14 treatment was more conducive to prolonging the postharvest storage period of blueberries and had the best effect in delaying the decline in fruit quality. Thus, combined 1-MCP and B. altitudinis Y-14 treatment may be an effective way to improve the storage quality and extend the storage period of blueberries, which provides a new way for storing and transporting blueberries to reduce costs and improve economic benefits.

The impact of 1-methylcyclopropene post-harvest treatment on the storability of the Ckifske zoloto and Dmiana apple varieties

As a result of the conducted research, it was established that the post-harvest treatment of apple fruits with Oberigpro, the active substance of which is 1-methylcyclopropene, helps to extend the duration of their storage in the conditions of an ordinary cooled atmosphere. In addition, the processed fruits had a 14-day post-storage shelf life during which they did not lose their quality, which allows producers to extend the duration of the sales period. The fruits of the varieties treated with 1-methylcyclopropene were harder than the control ones when removed from storage. After 60 days of storage, control apples had 21.8 N less pulp hardness than treated apples. During the 14 days of the shelf life, during which the apples were at a temperature of + 19 ºC, the hardness of their pulp in the version with treatment did not significantly decrease, unlike the version where 1-methylcyclopropene treatment was not applied. During the first month of storage, an increase in the content of soluble solids (TSS) was observed in the fruits of the Dmiana variety from the variant where post-harvest processing was carried out. Control fruits on the 150th day of storage contained 0.20% titratable acids, which is 0.10% less than those treated with 1-methylcyclopropene. On the 7th day of the expiration date, the acidity of Dmiana was 0.17 in the control and 0.25% in the fruits from the experimental variant, which is 0.20 and 0.28% less than that during storage, respectively. During the shelf life, fruit weight loss in both versions of the research increased, and on the 14th day, in the version treated with 1-methylcyclopropene, the Skifske Zoloto variety was 0.76% less, and the Dmiana variety was 1.59% less than in options without processing. With the growth of mass loss, the damage of the fruit withering increased, which negatively affected their appearance. On the 14th day of the post-harvest shelf life, Dmiana apples from the variant where 1-methylcyclopropene was not used were covered with an oily coating, and Skifske Zoloto 100% were affected by tan.

Evaluating the potential of 1-methylcyclopropene treatments on physicochemical properties, bioactive compounds, and shelf life of mango fruits under different storage conditions

The effect of 1-methylcyclopropene (1-MCP) treatments and storage conditions in the regulation of the physicochemical and bioactive properties of mango fruits (Mangifera indica L. cv. BARI-4) were investigated during storage. Different concentrations of 1-MCP treated samples (T0 = Control, T1 = 0.5 μL/L, T2 = 1.0 μL/L, T3 = 1.5 μL/L, and T4 = 2.0 μL/L) were stored in developed storage structure (10±1 °C and 90 % RH), cold storage (3 ± 1 °C and 80 ± 2 % RH), and ambient storage (29 ± 3 °C and 65 ± 2 % RH). The change in fruit quality including weight loss, firmness, surface color, storage life, chemical, and bioactive properties were studied periodically at 10, 20, 30 and 40 days of storage. The results demonstrated that 1-MCP treatment effectively maintained the quality of fruits by retarding the loss of weight, firmness, total soluble solids (TSS), and titratable acidity, which were served as a quality parameter during storage. The 1-MCP treatment dramatically delayed the change in color, quality measures, and bioactive properties compared to the control group. The storage condition greatly influenced the postharvest quality value and storage life. In combination with the developed storage structure and 1-MCP treatment preserved the acceptability of fruits to a great extent for around 40 days. The T2 = 1.0 μL/L 1-MCP treatment preserved the fruit quality for the highest days of storage 14, 34, and 46 days in ambient storage, cold storage, and develop storage structure respectively. The developed storage structure (10 ± 1 °C and 90 % RH) with 1-MCP (1.0 μL/L) treatment suggested the optimum storage ability for preserving the postharvest storage life of mango fruits. By implementing these findings mango growers and suppliers can reduce post-harvest losses, expand market reach, and provide consumers with high-quality mangoes that retain their quality for an extended period.

Dynamics of quality and metabolic activity of stored ‘Galaxy’ apples affected by maturity and 1-methylcyclopropene

ABSTRACT To preserve the quality traits of late-harvested ‘Galaxy’ apples during extended storage, the effects of 1-methylcyclopropene (1-MCP) treatment and storage conditions on postharvest quality were analysed. Alongside quality measures, indicators like ethylene production, respiration rate, aminocyclopropane-1-carboxylic acid oxidase (ACO) activity, and membrane permeability were assessed. Apples were harvested at an optimal harvest date or later and stored for 7 months at 1°C under regular atmosphere or controlled atmosphere. Treatments with 1–MCP at 300, 600 or 900 nL L−1 were applied pre- or post-storage. After 7 days shelf-life, apples subjected to 1-MCP and controlled atmosphere exhibited reduced ethylene production, respiration rate, and ACO activity compared to untreated or regular atmosphere counterparts. While the time of 1-MCP application and its concentration did not impact the respiration rate during shelf-life, controlled atmosphere effectively decreased it. The combination of controlled atmosphere and 1–MCP pre-storage was most effective in lowering ACO activity. Irrespective of conditions, 1-MCP curtailed ethylene production, respiration rate, and ACO activity during shelf-life, alleviating firmness and acidity loss. Only controlled atmosphere preserved quality and minimised disorders for optimally harvested apples, not late-harvested ones. None of the treatments maintained late-harvested apples’ quality after long-term storage plus shelf-life.

Involvement of BcERF109 in 1-MCP-delayed yellowing of pak choi (Brassica rapa subsp. Chinensis) via mitigation of major chlorophyll-degrading gene expression during storage

Leaf yellowing is a typical senescence symptom in postharvest pak choi (Brassica rapa subsp. Chinensis). Ethylene response factors (ERFs) are considered important regulators of leaf senescence. This study explored the likely regulatory effects of BcERF on pak choi yellowing via 1-methylcyclopropene (1-MCP) treatments. We identified an ERF transcription factor (TF), BcERF109, which may be involved in ethylene-induced pak choi yellowing. Treatment with 5.0 µL L–1 1-MCP suppressed the transcripts of chlorophyll catabolism genes (BcPPH1, BcRCCR, BcSGR2, and BcNYC1), inhibited decreases in chlorophyll content and chlorophyll fluorescence parameters, delayed chloroplast disintegration, and eventually mitigated yellowing. The treatment also blocked ethylene production and impeded the activities and transcripts of ethylene synthesis enzymes (ACC oxidase [ACO] and 1-aminocyclopropene-1-carboxylate [ACC] synthase [ACS]). In contrast, treatment with 10.0 µL L–1 ethylene accelerated pak choi yellowing, as indicated by greater ethylene production, activities and transcripts of ACO and ACS, and expression of chlorophyll catabolism genes, as well as reductions in chlorophyll content and fluorescence parameters. BcERF109 was identified as a nuclear-localised protein; its transcription levels were downregulated by 1-MCP and upregulated by ethylene. Molecular biology assays revealed that BcERF109 enhanced the transcriptional capacities of BcPPH1, BcRCCR, BcNYC1, and BcSGR2 by binding to their promoters. The transient overexpressing of BcERF109 in tobacco leaves stimulated the expression of endogenous genes (BcPPH1, BcRCCR, BcNYC1, BcSGR2, and BcERF109), leading to accelerated chlorophyll degradation and leaf yellowing. The application of 1-MCP mitigated pak choi yellowing by influencing ethylene synthesis and modulating the regulatory effects of BcERF019 on genes associated with chlorophyll catabolism. These results revealed a new regulatory mechanism involving ERF TFs in 1-MCP-induced delayed yellowing of green vegetables.

Evaluation of Color and Pigment Changes in Tomato after 1-Methylcyclopropene (1-MCP) Treatment.

The Polar Qualification System (PQS) was applied on hue spectra fingerprinting to describe color changes in tomato during storage. The cultivar 'Pitenza' was harvested at six different maturity stages, and half of the samples were subjected to gaseous 1-methylcyclopropene (1-MCP) treatment. Reference color parameters were recorded with a vision system colorimeter instrument, and the fruit pigment concentration was assessed with the DA-index®. Additionally, acoustic firmness (Stiffness) was measured. All acquired reference parameters were used to grade fruit in the supply chain. The applied 1-MCP treatments were used to control the ripening of climacteric horticultural produce. Both the DA-index® and stiffness values, presented as chlorophyll concentration and acoustic firmness, showed significant differences among maturity stages and treated and control samples and in their kinetics during storage. The machine vision parameter PQS-X was significantly affected by 1-MCP treatment (F = 10.18, p < 0.01), while PQS-Y was primarily affected by storage time (F = 18.18, p < 0.01) and maturity stage (F = 11.15, p < 0.01). A significant correlation was achieved for acoustic firmness with normalized color (r > 0.78) and PQS-Y (r > 0.80), as well as for the DA-index® (r > 0.9). The observed color changes agreed with the reference measurements. The significant statistical effect on the PQS coordinates suggests that hue spectra fingerprinting with this data compression technique is suitable for quality assessment based on color.

1-MCP treatment improves the postharvest quality of Jinxiu yellow peach by regulating cuticular wax composition and gene expression during cold storage.

This study aimed to analyze the effect of 1-methylcyclopropene (1-MCP) treatment on the postharvest quality, epidermal wax morphology, composition, and gene expression of Jinxiu yellow peach during cold storage. The results showed that 1-MCP treatment could maintain the postharvest quality of peach fruit as compared to control (CK) during cold storage. The wax crystals of peach fruit were better retained by 1-MCP, and they still existed in 0.6 and 0.9 µL/L 1-MCP treated fruit at 36 days. The total wax content in all the fruit increased first and then decreased during cold storage. Meanwhile, n-alkanes and primary alcohols were the main wax components. Compared to CK, 1-MCP treatment could delay the reduction of wax content during cold storage. The correlation analysis indicated that the postharvest quality of yellow peach was mainly affected by the contents of fatty acids and triterpenoids in cuticular wax. The transcriptomics results revealed PpaCER1, PpaKCS, PpaKCR1, PpaCYP86B1, PpaFAR, PpaSS2, and PpaSQE1 played the important roles in the formation of peach fruit wax. 1-MCP treatment upregulated PpaCER1 (18785414, 18786441, and 18787644), PpaKCS (18774919, 18789438, and 18793503), PpaKCR1 (18790432), and PpaCYP86B1 (18789815) to deposit more n-alkanes and fatty acids during cold storage. This study could provide a new perspective for regulating the postharvest quality of yellow peach in view of the application of cuticular wax. PRACTICAL APPLICATION: 'Jinxiu' yellow peach fruit is favorable among consumers because of its high commercial value. However, it ripens and deteriorates rapidly during storage, leading to serious economic loss and consumer disappointment. The effect of 1-methylcyclopropene (1-MCP) treatment on the postharvest quality, epidermal wax morphology, composition, and genes regulation of 'Jinxiu' yellow peach during cold storage was assessed. Compared to control, 1-MCP treatment could retain the storage quality of yellow peach by affecting cuticular wax composition and gene expression. This study could provide new perspective for regulating the postharvest quality of yellow peach in view of the application of cuticular wax.

Impacts of 1-methylcyclopropene (1-MCP) and ethephon treatments on expression of aquaporin (AQP) genes during apple fruit ripening

The main aim of the present study was to determine the effects of ethephon (ET) and 1-methylcyclopropene (1-MCP) treatments on expression of aquaporin (AQP) genes during apple fruit ripening. The harvested apples were treated with 1-MCP (1 μL L−1) and ET (0.2 mmol L−1), respectively, and then ripened at room temperature (20 ± 1 °C). Our results suggested that 1-MCP application reduced weight loss, total soluble solids (TSS) content, respiration rate and ethylene production, maintained flesh firmness, and slowed down the increase in content of soluble sugar and the decrease in content of titratable acidity (TA) and dry matter concentration (DMC) in flesh and peel during ripening compared with the control, while ET treatment had the opposite effects. Quantitative real-time PCR (qPCR) analysis indicated that MdAQPs expression was differentially regulated by both treatments in flesh and peel during ripening. Expression of MdSIP1;2 and MdNIP5;3 in flesh and MdPIP1;3 and MdPIP2;7 in peel was generally up-regulated by both treatments, while MdTIP4;2 expression in peel was down-regulated by both treatments during ripening. Expression of MdNIP1;1, MdNIP2;1 and MdTIP1;1 in flesh and MdTIP2;2, MdTIP3;1 and MdNIP5;1 in peel was differentially down-regulated by ET treatment while differentially up-regulated by 1-MCP application during ripening. Transcript levels of MdTIP2;2, MdPIP1;2, MdPIP2;4, MdPIP2;3 and MdNIP5;2 in flesh and MdNIP2;1, MdSIP2;2, MdSIP1;2 and MdNIP1;1 in peel were differentially up-regulated by ET application while differentially reduced by 1-MCP application during ripening. After transient over-expression of MdERF2, MdAQPs exhibited varying expression profiles in both tissues during ripening. The results indicated that MdAQPs expression was modulated by ethylene signal in ripening apple fruit.

Effects of Chitosan and 1-MCP on the Physical and Chemical Quality of Salak “Pondoh” (Salacca edulis REINW.) Fruits

Salak, or snake fruit, is a tropical fruit with a short shelf life when stored at room temperatures. The fruit’s base, if injured or bruised, can serve as an entry point for microbes, leading to physical and chemical damage to the fruits. This research aims to determine if chitosan and 1-methylcyclopropene (1-MCP) treatment can prolong the shelf life of salak “Pondoh”. The study tested two factors, chitosan (0%, 0.5%, 1.0%, 1.5%) and 1-MCP concentrations (0, 0.5, 1.0, 1.5 µL.L-1). The findings indicate that the application of chitosan and 1-MCP treatments did not significantly extend the shelf life of the fruits on the 15th day of observation. However, 1.0% chitosan combined with 1.5 µL.L-1 1-MCP and 1.5% chitosan combined with 0.5 µL.L-1 1-MCP proved effective in enhancing the fruit’s overall quality and maintained low ethylene production, high water content, and enhanced the organoleptic attributes including ease of peeling, fruit flesh color, texture, aroma, and taste.

Aminoethoxyvinylglycine and 1-methylcyclopropene treatments affect fruit quality and ethylene production in ‘Geum Hwang’ peach

Aminoethoxyvinylglycine and 1-methylcyclopropene treatments affect fruit quality and ethylene production in ‘Geum Hwang’ peach

Preharvest 1-methylcyclopropene (1-MCP) treatment effects on quality of spot and strip picked ‘Gala’ apples at harvest and after storage as affected by postharvest 1-MCP and temperature conditioning treatments

‘Gala’ apples are susceptible to development of stem-end flesh browning and subsequently flesh browning (FB) throughout the fruit during storage. Factors causing the browning are not well understood. In this study, fruit were obtained from an orchard block either untreated or treated with preharvest 1-methylcyclopropene (1-MCP; Harvista™) at two different harvest dates, one week apart. Preharvest 1-MCP was applied 7 d before the first harvest. Based on the commercially acceptable red coloration (66%), fruit were spot picked at the first harvest date, stripped picked at the second harvest date, or the remaining fruit from the first spot pick harvested on the second harvest date. Fruit were then untreated or treated with 1-MCP after overnight cooling to 0.5 °C (no conditioning treatment) or 10 °C for temperature conditioning (10 °C for 7 d), followed by storage in 2 kPa O2/2 kPa CO2 at 0.5 °C for 6 months. Fruit were generally less mature when harvested at H1 (spot pick) than at H2 (spot or strip pick), and with preharvest 1-MCP than without, and had the lowest FB incidence after storage. The picking method did not affect fruit maturity or FB incidence, but strip picked fruit softened more in storage than selective picked fruit. Overall, FB incidence was reduced by 5.9-, 1.2- and 1.6-fold by preharvest 1-MCP, postharvest 1-MCP and by conditioning, respectively. IAD values (higher values reflect higher chlorophyll concentrations) at harvest were positively correlated with flesh firmness, and negatively correlated with FB incidence. Preharvest 1-MCP treatment and early harvest contributes to reduced risk of FB development during storage of ‘Gala’ apples.

The apple transcription factor MdZF-HD11 regulates fruit softening by promoting Mdβ-GAL18 expression.

Fruit ripening and the associated softening are major determinants of fruit quality and post-harvest shelf life. Although the mechanisms underlying fruit softening have been intensively studied, there are limited reports on the regulation of fruit softening in apples (Malus domestica). Here, we identified a zinc finger homeodomain transcription factor MdZF-HD11that trans-activates the promoter of Mdβ-GAL18, which encodes a pectin-degradation enzyme associated with cell wall metabolism. Both MdZF-HD11 and Mdβ-GAL18 genes were up-regulated by exogenous ethylene treatment and repressed by 1-methylcyclopropene treatment. Further experiments revealed that MdZF-HD11 binds directly to the Mdβ-GAL18 promoter and up-regulates its transcription. Moreover, using transgenic apple fruit calli, we found that overexpression of Mdβ-GAL18 or MdZF-HD11 significantly enhanced β-galactosidase activity, and overexpression of MdZF-HD11 induced the expression of Mdβ-GAL18. We also discovered that transient overexpression of Mdβ-GAL18 or MdZF-HD11 in 'Golden Delicious' apple significantly increased the release of ethylene, reduced fruit firmness, promoted the transformation of skin color from green to yellow, and accelerated ripening and softening of the fruit. Finally, the overexpression of MdZF-HD11 in tomato also promoted fruit softening. Collectively, these results indicate that ethylene-induced MdZF-HD11 interacts with Mdβ-GAL18 to promote the post-harvest softening of apple.

Influence of Post-Harvest 1-Methylcyclopropene (1-MCP) Treatment and Refrigeration on Chemical Composition, Phenolic Profile and Antioxidant Modifications during Storage of Abate Fétel Pears.

'Abate Fétel', a winter cultivar, is the most important pear cultivar in Italy; its fruits are appreciated by consumers for their aroma, texture and balanced sweet and sour taste. Maintaining high-quality characteristics to prolong the shelf-life of fruit and preserve the sensory and nutritional quality is a priority for the food industry. The aim of our study was to test the effectiveness of 1-methylcyclopropene (1-MCP) and cold storage in prolonging the shelf-life of these fruits, which were harvested at maturity at two different times. This work focused on the effects of different storage treatments and two ripening times on (i) the chemical composition of Abate Fétel pulp fruits to preserve their sweet taste and aroma and (ii) the phenolic profile composition and antioxidant activity of the peel, which is naturally rich in phytochemicals and important for the fruit's shelf-life and in the functional food industry for its high nutritional value. Abate Fétel fruits were harvested at the optimal commercial maturity stage, first on 15 September, having been treated with 1-MCP and stored for 2 months at cold temperatures; the other fruits were harvested at the end of September and stored in a cold cell for 2 months. The fruit pulp was tested for glucose and fructose, pH, acidity and organic acids (malic, citric, fumaric and shikimic), phenolic content and phenolic compounds (chlorogenic and caffeic acids, rutin, hyperoside, kaempferol-3-rutinoside and isoquercitrin), and the antioxidant activities in the fruit peels were measured. Treating the fruits with 1-MCP better preserved the phytochemical compounds compared to simple refrigeration, preserving the fruit's quality and prolonging its shelf-life. All the treatments help to maintain the glucose and fructose content and the acidity, preserving the aroma and organoleptic characteristics.

Effect of 1-Methylcyclopropene (1-MCP) Treatment and MAP on Quality Changes of Peach ‘Daehong’ during Cold Storage

Effect of 1-Methylcyclopropene (1-MCP) Treatment and MAP on Quality Changes of Peach ‘Daehong’ during Cold Storage

Integrated analysis of nutritional quality changes and molecular regulation in ‘Qingcui’ plum fruit treated with 1-MCP during storage

To elucidate the effect of 1-Methylcyclopropene (1-MCP) treatment on molecular and nutritional quality changes during ‘Qingcui’ plum fruit ripening, metabolomic profiling and transcriptome analysis were conducted to identify key metabolites and differentially expressed genes. Application of 1-MCP suppressed ‘Qingcui’ plum fruit softening and maintained higher soluble solids content. Metabolome profiling identified numerous metabolites that differentially accumulated during ripening and significantly contributed to the nutritional quality of plum fruit. These included sugars, organic acids, amino acids, and phenolic compounds. A special focus was given to twelve phenolic-related metabolites that were reduced by 1-MCP treatment during ripening. Transcriptome profiling revealed the enrichment of transcription factors and biosynthetic genes related to phenolic-related metabolites among differentially expressed genes, indicating that 1-MCP likely influences phenolic-related metabolite levels through transcriptional regulation of their biosynthetic pathways. This integrated analysis of metabolome and transcriptome data provides new insights into the complex mechanisms controlling the nutritional quality of ‘Qingcui’ plum fruit in response to 1-MCP. Understanding the regulatory networks influencing plum fruit ripening can be valuable for enhancing its nutritional value and facilitating future plum breeding efforts.

Impact of Cultivation and Storage Conditions on Total Mal d 1 Content and Isoallergen Profile in Apples.

The allergen Mal d 1 is often responsible for adverse allergic reactions to fresh apples in northern and central Europe. The Mal d 1 content and isoallergen profile are proposed to have an impact on the allergenic potential of the fruit. Therefore, we investigated the impact of the cropping system on the Mal d 1 content and the isoallergen profile of apples by mass spectrometry for the varieties 'Jonagored' and 'Topaz'. To monitor the impact of storage time and conditions, apples of the varieties 'Santana' and 'Jonagold' were stored for up to 12 weeks under regular air (RA), under RA in combination with 1-methylcyclopropene (1-MCP) treatment, and under a controlled atmosphere (CA). The impact of the cropping system (integrated production vs organic production) was negligible. However, a significant increase in the Mal d 1 content during storage was observed, being higher when stored under CA conditions than under RA conditions. An additional treatment with 1-MCP prior to RA storage drastically reduced the level of Mal d 1 expression in the flesh of the apples by ∼50%. Furthermore, the content of isoallergens 1.03 and 1.06 increased disproportionately under CA conditions, while under RA conditions, only isoallergen 1.06 was affected. With the 1-MCP treatment, no changes in the isoallergen profile were obvious.

Effects of 1-Methylcyclopropene Treatment on the Quality and Malic Acid Metabolism of ‘Xiangjiao’ Plum under Low-Temperature Storage

‘Xiangjiao’ plum (Prunus salicina Lindl.) is a stone fruit that is vulnerable to the chilling injury (CI) that is caused by low-temperature stress. The effects of 1-methylcyclopropene (1-MCP) and ethylene absorbent (EA) treatments on the fruit quality and malic acid metabolism of ‘Xiangjiao’ plum stored at 4 °C were compared in this study. Compared with the control check (CK) and EA treatment, fumigation with 1.0 mg·L−1 of 1-MCP for 24 h could more significantly maintain the sensory and physiological quality of the fruit, increase the activity of antioxidant enzymes, and prolong the storage time of plums. Furthermore, 1-MCP treatment can regulate the high expression of the tonoplast dicarboxylate transporter (tDT) and phosphoenolpyruvate carboxylase (PEPC) gene, regulate the high expression of the NAD-malate dehydrogenase (NAD-MDH) gene at the end of storage, and inhibit the expression of the NADP-malic enzyme (NADP-ME) gene. These changes resulted in increased NAD-MDH enzyme activity and decreased NADP-ME enzyme activity, which inhibited the degradation of malic acid that is caused by CI. As a result, 1-MCP can effectively maintain the storage quality of ‘Xiangjiao’ plum, reduce the loss of pleasant sour taste, and improve the edible flavor and commercial value of the fruit.