Improving the ripening process after 1-MCP application: Implications and strategies

Novel Post-Harvest Preservation Techniques for Edible Fungi: A Review

Edible fungi are well known for their rich nutrition and unique flavor. However, their post-harvest shelf-life is relatively short, and effective post-harvest preservation techniques are crucial for maintaining their quality. In recent years, many new technologies have been used for the preservation of edible fungi. These technologies include cold plasma treatment, electrostatic field treatment, active packaging, edible coatings, antimicrobial photodynamic therapy, and genetic editing, among others. This paper reviews the new methods for post-harvest preservation of mainstream edible fungi. By comprehensively evaluating the relative advantages and limitations of these new technologies, their potential and challenges in practical applications are inferred. The paper also proposes directions and suggestions for the future development of edible fungi preservation, aiming to provide reference and guidance for improving the quality of edible fungi products and extending their shelf-life.

Lily (Lilium spp.) LhERF4 negatively affects anthocyanin biosynthesis by suppressing LhMYBSPLATTER transcription

Anthocyanins are among the main pigments involved in the colouration of Asiatic hybrid lily (Lilium spp.). Ethylene, a plant ripening hormone, plays an important role in promoting plant maturation and anthocyanin biosynthesis. However, whether and how ethylene regulates anthocyanin biosynthesis in lily tepals have not been characterized. Using yeast one-hybrid screening, we previously identified an APETALA2 (AP2)/ETHYLENE RESPONSE FACTOR (ERF) named LhERF4 as a potential inhibitor of LhMYBSPLATTER-mediated negative regulation of anthocyanin biosynthesis in lily. Here, transcript and protein analysis of LhERF4, a transcriptional repressor, revealed that LhERF4 directly binds to the promoter of LhMYBSPLATTER. In addition, overexpression of LhERF4 in lily tepals negatively regulates the expression of key structural genes and the total anthocyanin content by suppressing the LhMYBSPLATTER gene. Moreover, the LhERF4 gene inhibits anthocyanin biosynthesis in response to ethylene, affecting anthocyanin accumulation and pigmentation in lily tepals. Collectively, our findings will advance and elucidate a novel regulatory network of anthocyanin biosynthesis in lily, and this research provides new insight into colouration regulation.

One-pot co-crystallized hexanal-loaded ZIF-8/quaternized chitosan film for temperature-responsive ethylene inhibition and climacteric fruit preservation

Controlling ethylene production and microbial infection are key factors to prolong the shelf life of climacteric fruit. Herein, a nanocomposite film, hexanal-loaded ZIF-8/CS (HZCF) with "nano-barrier" structure, was developed by a one-pot co-crystallized of ZIF-8 in situ growth on quaternized chitosan (CS) and encapsulation of hexanal into ZIF-8 via microporous adsorption. The resultant film realized the temperature responsive release of hexanal via the steric hindrance and hierarchical pore structure as "nano-barrier", which can inhibit ethylene production in climacteric fruit on demand. Based on this, the maximum ethylene inhibition rate of HZCF was up to 52.6 %. Meanwhile, the film exhibits excellent antibacterial, mechanical, UV resistance and water retention properties, by virtue of the functional synergy between ZIF-8 and CS. Contributed to the multifunctional features, HZCF prolonged the shelf life of banana and mango for at least 16 days, which is 8 days longer than that of control fruit. More strikingly, HZCF is washable and biodegradable, which is expected to replace non-degradable plastic film. Thus, this study provides a convenient novel approach to simplify the encapsulation of active molecule on metal-organic frameworks (MOFs), develops a packaging material for high-efficient freshness preservation, and helps to alleviate the survival crisis caused by food waste.

Postharvest Management of Fruits and Vegetables-Series II

Fruits and vegetables are crucial nutritional sources of carbohydrates, protein, minerals, vitamins, and dietary fiber, offering significant benefits to human health [...].

Effect of calcium spray at flowering combined with post-harvest 1-MCP treatment on the preservation of grapes

These tests were carried out to find out how calcium and 1-MCP treatment affected the preservation of grapes, as grapes are highly susceptible to decay during post-harvest storage. The grapes were treated with 5 g/L calcium at the flowering stage, followed by 1 μL/L 1-MCP treatment after harvesting. When grapevines were treated with a combination of calcium and 1-MCP, the marketable fruit rate (At day 56 of storage, the 1-MCP + Ca2+ treatment group was still 93%, an increase of 29.03% compared to the control group.) and quality improved (At day 28 of storage, the VC content of the 1-MCP + Ca2+ treated group was 4.35 mg/100g, an increase of 25.01% compared to the control group.), while the fruit weight loss rate decreased (At day 56 of storage, the weight loss of the control group was 6.97%, an increase of 39.43% compared to the 1-MCP + Ca2+ treated group.). According to the experimental results, there are several reasons for this. First, in the early stages of fruit storage, the concentration of soluble pectin and soluble fiber, as well as the activities of pectinase and cellulase (related gene levels) were decreased. Secondly, the activity of antioxidant enzymes was increased, while MDA content was decreased. Third, during fruit storage, the respiratory intensity and ethylene release rate were reduced, as was the activity of energy metabolism enzymes. As a result, the aging and deterioration of the fruit during storage were delayed. Principal component analysis revealed that the calcium and 1-MCP combination therapy slowed the decline in grape berry quality, followed by the calcium-treated and 1-MCP-treated fruits. In contrast, grape berry quality declined the most rapidly in the control group.

1-Methylcyclopropene treatment delays the softening of Actinidia arguta fruit by reducing cell wall degradation and modulating carbohydrate metabolism

The rapid softening of hardy kiwifruit (Actinidia arguta) fruit significantly reduces its marketing potential. Therefore, the effect of 1-methylcyclopropene (1-MCP) on the softening of A. arguta fruit was investigated. Results indicated that A. arguta fruit treated with 1-MCP maintained a higher level of firmness, titratable acidity, ascorbic acid, total phenolics, and flavonoids content, relative to non-treated fruit. Fruit treated with 1-MCP and placed in long-term cold storage had higher sensory scores, as determined by a taste panel and supported by electronic nose and tongue data. Notably, 1-MCP delayed the degradation of cell wall components, including pectin, cellulose, and hemicellulose, by reducing the activity of cell-wall-modifying enzymes. In addition, 1-MCP reduced the activity of carbohydrate metabolism-related enzymes, resulting in fruit with higher levels of starch and sucrose and lower levels of glucose, fructose and sorbitol. Collectively, these results indicate that 1-MCP can be used to delay the softening of A. arguta fruit and extend its storage and shelf life.

Platinum-loaded dendritic mesoporous silica as novel ethylene scavenger to extend shelf life of banana (Musa nana)

Ethylene, released from fruits and vegetables (F&V) after harvest and during storage, often accelerates the ripening or over-ripening and may be caused decay, leading to substantial economic loss. Dendritic mesoporous silica supported (DMS) platinum (Pt/DMS) catalyst as ethylene scavenger was prepared and various characterization results indicated that the as-prepared Pt/DMS with ultra-low Pt loading exhibited excellent ethylene scavenging performance, which could maintain the complete ethylene conversion (100%) over 50 h at 25 °C and even 0 °C for 100 min with superior consecutive cycles by repeating the use of Pt/DMS. The presence of Pt/DMS delayed banana softening, and browning, reduced weight loss and kept the freshness for 14 days. In conclusion, the active packaging incorporated with Pt/DMS catalysts with high ethylene scavenging efficiency is expected to be extremely beneficial to the post-harvest storage life of other fruits and vegetables that needs further related investigation.

1-Methylcyclopropene counteracts ethylene promotion of fruit softening and roles of MiERF2/8 and MiPG in postharvest mangoes

Ethylene burst is an important sign of the initiation of postharvest mango ripening and softening is a typical characteristic of fruit ripening. However, the intrinsic link between ethylene release and fruit softening during ripening of postharvest mangoes is still not clear. The aim of this study was to investigate the effects of ethylene and its action inhibitor 1-methylcyclopropene (1-MCP) on fruit softening and ripening and the underlying regulatory mechanisms. Results showed that ethephon (ETH) promoted ethylene release and enhanced MDA content and activities of cell wall degrading enzymes, whereas 1-MCP treatment exhibited an opposite effect. Moreover, real-time quantitative polymerase chain reaction indicated that the transcription levels of genes involved in cell wall degradation (MiPG, Miβ-GAL and MiPE), ethylene biosynthesis (MiACO1 and MiACS6) and ethylene response factor (MiERF8) were remarkably induced by ETH. Correlation analysis further revealed that the production of ethylene was significantly negatively correlated with firmness, but positively correlated with MDA content, activities of cell wall degrading enzymes and expressions of MiPG and Miβ-GAL. Furthermore, yeast one hybrid (Y1H) assay showed that MiERF2 and MiERF8 could directly bind to the promotor of MiPG and then regulate its transcription. These findings suggest that ethylene production is closely associated with fruit softening, and MiERF2 and MiERF8 and MiPG may play crucial roles in regulation of ripening and softening of postharvest mangoes.

Genome-Wide Identification and Comprehensive Analysis of the AP2/ERF Gene Family in Pomegranate Fruit Development and Postharvest Preservation

Pomegranate (Punica granatum L.) is a kind of fruit with significant economic, ecological and health values. AP2/ERF transcription factors belong to a large group of factors mainly found in plants and play key roles in plant growth and development. However, AP2/ERF genes in pomegranate and their implication in development and postharvest preservation have been little described. In this study, 116 PgAP2/ERF genes in pomegranate were identified and renamed based on their chromosomal distributions. Phylogenetic relationship with genes from other species, structures, duplications, annotations, cis-elements in promoter sequences, and protein-protein interaction networks among PgAP2/ERF proteins were comprehensively explored. Expression analysis revealed several PgAP2/ERFs associated with the phenotypes of pomegranate seed hardness, including PgAP2/ERF5, PgAP2/ERF36, PgAP2/ERF58, and PgAP2/ERF86. Subsequent analysis indicated that many differentially expressed PgAP2/ERF genes are potentially important regulators of pomegranate fruit development. Furthermore, expression of more than one-half of PgAP2/ERFs was repressed in ‘Tunisian soft seed’ pomegranate fruit under low-temperature cold storage. The results showed that 1-MCP implicated in promoting postharvest preservation of ‘Tunisian soft seed’ pomegranate upregulated the PgAP2/ERF4, PgAP2/ERF15, PgAP2/ERF26, PgAP2/ERF30, PgAP2/ERF35 and PgAP2/ERF45 genes compared to those under low-temperature cold storage. This indicates that these genes are important candidate genes involved in pomegranate postharvest preservation. In summary, the findings of the present study provide an important basis for characterizing the PgAP2/ERF family genes and provide information on the candidate genes involved in pomegranate fruit development and postharvest preservation.

Application of ethylene for ripening of 1-MCP treated pear after cold storage

This work aimed to evaluate the effect of ethylene treatment on ripening of 1-MCP treated pear after 6 months of cold storage. Pear treated with gaseous 1-MCP at 625–650 ppb for 24 h at 0 °C was stored at 0 °C for 6 months with normal air, and treated groups were exposed to 100 ppm ethylene at 20 °C for 24 h. After that, samples were kept at 0, 10, and 15 °C for 2 weeks. Stiffness, chlorophyll fluorescence, ethylene and CO2 production of fruit were investigated during 2 weeks. Application of ethylene resumed the ripening of pear after long term storage. The results showed that fruit treated with ethylene achieved more homogeneous surface colour in comparison with non ethylene treated pears. In addition, the ethylene and carbon dioxide production of ethylene treated pears had higher values than that of control. The ethylene treatment could accelerate the softening of pear. Temperature also has significant effect on ripening during storage. This study found that ethylene treatment could accelerate the normal ripening of 1-MCP treated pears.

Delay of 1-MCP Treatment on Post-Harvest Quality of ‘Bosc Kobak’ Pear

Information about 1-MCP application time on pears is crucial to optimize the schedule of treatment in commercial practice. In the present work, the effect of a 3, 5 and 7 d delay of 1-MCP treatment after harvest on ‘Bosc Kobak’ pears was investigated, with an emphasis on shelf life. Fruit was treated with 1-MCP (625 ppm) on the 3rd, 5th and 7th d after harvest for 24 h and then kept at 20 °C for 14 d or stored at 1 °C in normal atmosphere for 6 months. Ethylene, carbon dioxide production, flesh firmness, soluble solid content and color index was determined after 4 and 6 months of cold storage and an additional 7 d of shelf-life at 20 °C. Pears treated with 1-MCP had lower values in ethylene and carbon dioxide production after storage compared to the control group; in particular, fruit treated on the 3rd d after harvest obtained the lowest values. Moreover, flesh firmness of treated samples had a higher value than that of the others after cold storage and subsequent 7 d of shelf life at 20 °C. In addition, fruit treated on the 3rd d after harvest exhibited the slower change in surface color than that of other groups. However, 1-MCP treatment on the 5th and 7th d after harvest had a minor effect on firmness and surface color change after a long storage period. The effect of 1-MCP treatment depends on the time from harvest to application. The application of 1-MCP on the 3rd d after harvest obtained the highest efficacy. The results of this study provided information on scheduling the commercial 1-MCP application for ‘Bosc Kobak’ pears.

Harmony but Not Uniformity: Role of Strigolactone in Plants

Strigolactones (SLs) represent an important new plant hormone class marked by their multifunctional roles in plants and rhizosphere interactions, which stimulate hyphal branching in arbuscular mycorrhizal fungi (AMF) and seed germination of root parasitic plants. SLs have been broadly implicated in regulating root growth, shoot architecture, leaf senescence, nodulation, and legume-symbionts interaction, as well as a response to various external stimuli, such as abiotic and biotic stresses. These functional properties of SLs enable the genetic engineering of crop plants to improve crop yield and productivity. In this review, the conservation and divergence of SL pathways and its biological processes in multiple plant species have been extensively discussed with a particular emphasis on its interactions with other different phytohormones. These interactions may shed further light on the regulatory networks underlying plant growth, development, and stress responses, ultimately providing certain strategies for promoting crop yield and productivity with the challenges of global climate and environmental changes.