Blueberries are rich in anthocyanins, which have antioxidant properties. Anthocyanin content is an important indicator for evaluating blueberry quality. The mechanism of anthocyanin synthesis requires further clarification for blueberry breeding and cultivation regulation. This study mined the blueberry ERF gene family based on single-molecule real-time (SMRT) and Illumina transcriptome sequencing results, and further explored the gene function of VcERF061. In this study, a transient injection experiment was conducted on blueberry leaves and fruits. Compared to the control, the injection sites of leaves and fruits overexpressing VcERF061 showed significant anthocyanin accumulation. Similarly, in the blueberry transgenic adventitious shoot experiment, the anthocyanin content in the blueberry shoots and lateral buds of adventitious buds overexpressing the VcERF061 gene was significantly higher than that of transgenic adventitious shoots transformed with the empty vector, and a significant increase in the expression of VcMYB1, VcF3'5'H, VcDFR, VcANS, and VcUFGT. We then speculated whether VcERF061 interacts with structural genes to activate the expression of the structural gene VcANS promoter and promote anthocyanin synthesis. Unfortunately, after conducting a Y1H assay, we found that VcERF061 did not bind to the VcANS promoter, and there was no interaction between the two. Exogenous abscisic acid (ABA) and ethephon (ETH) treatment of blueberry fruit upregulated VcERF061 expression. Our previous study verified that VcMYB1 promotes the accumulation of blueberry anthocyanins, therefore, this study also analyzed VcMYB1 expression in ABA- and ETH-treated blueberry fruit, and found that the expression of VcMYB1 was also up-regulated in ABA- and ETH-treated blueberry fruits. The expression of VcMYB1 and VcERF061 were both up-regulated in ABA- and ETH-treated blueberry fruits, and both reached the maximum proportion after 12h of treatment. The yeast two-hybrid (Y2H) experiment showed that VcMYB1 and VcERF061 did not interact with each other at the protein-protein level, but yeast one-hybrid (Y1H) experiment and tobacco leaf transient injection experiment demonstrated that VcMYB1 transcription factor can bind to the promoter sequence of VcERF061 and promote the expression of the VcERF061 gene. In this study, we found that VcERF061 promoted blueberry anthocyanin accumulation, but did not directly bind to the promoters of structural genes such as VcANS. Both VcMYB1 and VcERF061 genes responded to exogenous ABA and ETH signals and exhibited similar expression patterns. There was an interaction between VcMYB1 and VcERF061. The findings of this study enrich the regulatory network of anthocyanin synthesis in plants and provide theoretical support for blueberry quality improvement.

Members of the WRKY transcription factors (TFs) family play crucial roles in biotic and abiotic stress responses in plants, but their roles in response to drought stress in maize (Zea mays L.) have not been fully elucidated. Maize ZmWRKY82, a group IIc WRKY gene, was isolated from maize using reverse transcription polymerase chain reaction (RT-PCR). Using the UniProt online database, we found that ZmWRKY82 encodes a 222-amino protein with conserved WRKYGKK and C-X4-C-X23-H-X1-H motifs. ZmWRKY82 is strongly induced by polyethylene glycol (PEG), abscisic acid (ABA), methyl jasmonate (MeJA), salicylic acid (SA), and ethephon (ETH) treatments. The ZmWRKY82 protein was located in the cell nucleus. ZmWRKY82 had transcriptional activation capability and was able to bind to the W-box element. ZmWRKY82-overexpressing Arabidopsis and maize exhibited stronger drought resilience, which was associated with enhanced antioxidant enzyme activity and altered transcription level of drought-related genes. These findings suggest that ZmWRKY82 plays a central role in conferring drought tolerance in maize and may contribute to crop improvement and sustainable agricultural practices.

Ethephon (ETH) is a widely used plant growth regulator in fruit production. Due to its harm to people’s health, its content is an important indicator for fruit quality control. However, due to the extremely high polarity and acidity, as well as the absence of chromophores, efficient and simple detection of ETH remains challenging. In this work, a convenient method for determining trace ETH in fruit was developed that involved a combination of catalytic methylation and gas chromatography-mass spectrometry (GC-MS) analysis. ETH in fruit was extracted with acetonitrile and derivatized with (trimethylsilyl) diazomethane (TMSD) by the catalysis of trimethylchlorosilane to generate methylated ETH (ETH-M) which was determined by GC-MS. The instrumental linear range of ETH was 10–1000 µg/L with a coefficient of determination (R2) > 0.999. The limit of detection (LOD) of the method was 1.0 µg/kg. The ETH content in 12 types of fruits was determined with a reasonable recovery rate ranging from 83.20 ± 0.05% to 118.21 ± 0.01%. The ETH content in the unwashed fruits was in the range of undetectable (ND) to 111 µg/g and below the LOD in their flesh. After washing, the content was significantly reduced and even undetectable. The established method showed good efficiency, selectivity, and reproducibility, and can be used for the determination of ETH in various fruits.

Certain European high-tannin cider apple ( Malus × domestica Borkh.) cultivars used for commercial production of craft hard cider (fermented apple juice) are known to have severe preharvest fruit drop, as well as asynchronous ripening. A 2-year (2018 and 2019) study at two commercial orchards in Wayne County, NY, USA, examined the effects on drop and ripeness of applying three plant growth regulators—aminoethoxyvinylglycine (AVG), ethephon (ETH), and 1-naphthaleneacetic acid (NAA)—on eight different cider apple cultivars. The treatments included i) untreated control, ii) ETH applied 1 week before harvest (WBH), iii) NAA applied 4 and 2 WBH, iv) NAA at 4 and 2 WBH plus ETH at 1 WBH, v) AVG at 4 and 2 WBH, and vi) AVG at 4 and 2 WBH plus ETH applied 1 WBH. Treatments had significant effects on fruit drop: AVG and NAA treatments significantly reduced drop, while NAA+ETH promoted drop, relative to the control. AVG delayed ripening, while NAA+ETH accelerated ripening. Cultivars that tended to have greater natural preharvest fruit drop had a greater reduction in fruit drop when treated with NAA or AVG. Our research can lead to more precise management of cider apple harvest. For example, NAA alone encouraged ripening while reducing drop, which would be advantageous for over-row machine harvest followed soon thereafter by fruit processing. NAA combined with ETH resulted in advanced ripening, reduced fruit detachment force, and fruit drop largely being condensed into the week leading up to harvest, which may be advantageous for shake-and-sweep mechanical harvest followed by short-term storage. AVG alone delayed ripeness and reduced fruit drop, while increasing flesh firmness and fruit detachment force, making this plant growth regulator (PGR) more suitable for hand harvest and long-term storage before processing.

Anthocyanins are important phenolic compounds in grape skins, affecting the color, oxidation resistance, and aging ability of red wine. In recent years, global warming has had a negative effect on anthocyanin biosynthesis in grape berries. Ethylene serves as a crucial phytohormone regulating the development and ripening processes of fruit; however, the specific molecular mechanism and the regulatory network between ethylene signaling and the anthocyanin biosynthesis pathway remain incompletely understood. In this study, 400 mg/L ethephon (ETH) solution was sprayed onto the surface of grape berries at the lag phase (EL-34), and the changes in anthocyanin-related genes and metabolites were explored through transcriptomic and metabolomic analysis. The results showed that ETH treatment increased Brix and pH in mature berries. In total, 35 individual anthocyanins were detected, in which 21 individual anthocyanins were enhanced by ETH treatment. However, the anthocyanin profile was not affected by exogenous ethylene. Transcriptomics analysis showed that there were a total of 825 and 1399 differentially expressed genes (DEGs) 12 h and 24 h after treatment. Moreover, key structural genes in the anthocyanin synthesis pathway were strongly induced, including VvPAL, VvCHS, VvF3H, VvF3'5'H, VvDFR and VvUFGT. At the maturity stage (EL-38), the expression levels of these genes were still higher in EHT-treated berries than in the control. ETH treatment also influenced the expression of genes related to hormone biosynthesis and signal transduction. The ethylene biosynthesis gene (VvACO), ethylene receptor genes (VvETR2, VvERS1 and VvEIN4), ABA biosynthesis gene (VvNCED2), and ABA receptor gene (VvPYL4) were up-regulated by ETH treatment, while the auxin biosynthesis gene (VvTAA3) and seven genes of the auxin-responsive protein were inhibited by exogenous ethylene. Meanwhile, ETH treatment promoted the expression of the sugar transporter gene (VvEDL16) and two sucrose synthase genes (VvSUS2 and VvSUS6). In EHT-treated berries, 19 MYB and 23 ERF genes were expressed differently compared with the control (p < 0.05). This study provides the theoretical foundation and technical support for the regulation of anthocyanin synthesis in non-climacteric fruit.

Chile contributes 4% of global hazelnut (Corylus avellana L.) production, mainly developed in temperate regions with high autumn rainfall and humidity during harvest, which can compromise nut quality and increase postharvest losses. Thus, synchronizing harvests has become a critical aspect for growers in the southern region of Chile. This study focused on the effects of ethephon (ETH) spraying on trees to optimize nut drop timing and assess its impact on yield optimization and its influence on vegetative growth and inflorescence activity. From the 2020/2021 to the 2022/2023 seasons, experiments were conducted on a commercial hazelnut orchard of Tonda di Giffoni (TDG) planted in southern Chile. Four ETH (0, 250, 500, 1000 mg L−1) treatments were sprayed 15 days preharvest and denoted as ETHA (sprayed 2020/2021) and ETHB (sprayed twice, in 2020/2021 and 2021/2022). Nut drop synchronization was periodically monitored at 7, 15, 21, 28, and 35 days after application (DAA), along with industrial quality parameters (nut weight, kernel yield) and inflorescence activity. In the first season, ETH significantly synchronized nut drops, achieving optimal results at 15–28 DAA with ETH 250 and 500, while ETH 1000 induced earlier drops but reduced yields. Total nut yield varied among seasons and demonstrated consistent performance of ETH 250, identified as the most efficient treatment for balancing nut drop timing. Industrial parameters showed seasonal differences but no adverse effects on nut quality. Conversely, the inflorescence activity remained unaffected by ETH concentrations. ETHA and ETHB treatments influenced tree shoot length variably across three seasons, showing significant concentration and seasonal interaction effects. These results demonstrate that ETH effectively synchronizes hazelnut harvests under temperate conditions, reducing post-harvest losses and optimizing logistics without compromising yield or quality.

ABSTRACTAPETALA2/ethylene response factor (AP2/ERF) transcription factors constitute a significant family of transcription factors that play crucial roles in plant growth and development. Meanwhile, organ abscission is common in the growth and development of fruit trees. In particular, the economically important sweet cherry (Prunus avium L.) is highly affected by excessive fruit abscission, limiting its yield and economic benefits. Previous research identified the potential involvement of PavRAP2.3 (RELATED TO AP2.3) of the AP2/ERF family in fruit abscission based on the significantly higher PavRAP2.3 expression levels in abscised tissues. This study found the highest PavRAP2.3 expression level in mature fruits and significantly increased PavRAP2.3 expression in leaves treated with abscisic acid (ABA) and ethephon (ETH). PavRAP2.3 was localized in the nucleus and exhibited transcriptional activity in Y2H gold yeast. Yeast one‐hybrid assays and dual‐luciferase assays revealed that PavRAP2.3 induced abscission by regulating the PavCEL9‐like, a gene associated with cell wall reconstruction. Furthermore, PavRAP2.3‐overexpressing Arabidopsis thaliana exhibited promoted petal abscission, which was attributed to the upregulation of Cellulase 3 (CEL3), Mannase 7 (MAN7), ABA Insensitive 5 (ABI5), and ACC SYNTHASE6 (ACS6) genes. Therefore, PavRAP2.3 functions as a positive regulator involved in sweet cherry fruit abscission, chiefly via regulating PavCEL9‐like. These findings could facilitate breeding efforts aimed at reducing fruit abscission in sweet cherry, as well as better the understanding of the function of the AP2/ERF family.

Synergistic effects of Tween 20 and ethephon on yeast oil and β-carotene co-production by Rhodosporidium toruloides using purified biodiesel-derived crude glycerol as an alternative carbon source.

Fruit color is a crucial quality factor strongly influencing consumer preference for citrus. The coloration of citrus fruit is primarily determined by carotenoids, which produce a range of hues. Gibberellic acid (GA) and ethylene are critical in fruit coloration during the ripening process. Nevertheless, the underlying mechanisms remain poorly understood. The present study utilized transcriptomic and metabolomic analyses to investigate the molecular regulatory mechanisms affecting peel pigment metabolism in tangors (Citrus reticulata Blanco×Citrus sinensis L. Osbeck) following GA and ethephon (ETH) treatments. Collectively, our findings indicated that GA inhibits chlorophyll degradation and the accumulation of numerous carotenoids, including five violaxanthin esters (violaxanthin palmitate, violaxanthin myristate-caprate, violaxanthin myristate-laurate, violaxanthin dilaurate, violaxanthin myristate) and two β-cryptoxanthin derivatives (β-cryptoxanthin laurate, β-cryptoxanthin myristate), while ETH promotes these processes. Furthermore, GA inhibited the downregulation of lutein, the predominant carotenoid in immature fruits. Notably, integrated transcriptomic and metabolomic analyses identified 33 transcription factors associated with pigment metabolism. Of these, two novel transcription factors, the ethylene-responsive transcription factor ABR1 and the HD-Zip transcription factor ATHB7, were uncovered through both transcriptomic analysis and weighted gene co-expression network analysis. These two transcription factors positively regulated the colouration process, as validated by transient overexpression assays in tobacco. Taken together, our findings elucidated the global carotenoid changes and transcriptional alterations in regulating citrus peel color under hormone induction, with significant implications for improving citrus production.

Under the climate variability conditions of southern Brazil, post-flowering thinning is a safer practice than thinning during flowering. This study aimed to evaluate the effect of the application of post-flowering thinning agent on ‘Fuji Suprema’ apple when used in combinations. The experiment was carried out in an experimental orchard located in the municipality of Caçador, Santa Catarina, Brazil during the 2017 to 2020 harvest seasons. We tested treatments combining Benzyladenine (BA) with Ethephon (ET) or Metamitron (MM), as well as individual applications of each product at different concentrations on apple fruits. Applications were made individually or in tank mixes during post-flowering periods, with manual thinning when fruits were 8 to 12 mm in diameter and chemical thinning at 15 to 20 mm in diameter. Treatments were as follows: 1. Control (manual thinning); 2. BA (400 ml/100 L) + ET (200 ml/100 L); 3. BA (400 ml/100 L) + MM (100 g/100 L); 4. BA (600 ml/100 L); 5. ET (240 - 200 ml/100 L); MM (150 ml/100 L); MM (150 ml/100 L) + ET (200 ml/100 L). The results showed that the combination of Metamitron with Benzyladenine or Ethephon effectively regulated fruit set and enhanced fruit quality, making these combinations suitable for thinning under southern Brazil conditions.

Forthe first time a novel fluorescent La@ZrMOF nanomaterial was synthesizedfor the convenient and visual detection of ethephon (ETH) based on the ligand-metal charge transfer process. The fluorescence signal gradually enhanced as the concentration of ETH increased, accompanied by a change in the color from colorless to blue. The assay can be completed within 75min with a detection limit of 0.03mg/L. A paper-based approach for the rapid and visual determination of ETH has alsobeen devised, enabling the efficient used in a variety of actual products, with apples, pears, and tomatoes as examples. It proved to be simple, easy to use, and sensitive, and has the potential for further uses of ETH detection.

Plant height represents a pivotal agronomic trait for the genetic enhancement of crops. The plant cell wall, being a dynamic entity, is crucial in determining plant stature; however, the regulatory mechanisms underlying cell wall remodeling remain inadequately elucidated. This study demonstrates that the application of gibberellin 3 (GA3) enhances both plant height and cell wall remodeling in tomato (Solanum lycopersicum L.) plants. RNA sequencing (RNA-seq) results of GA3 treatment showed that the DEGs were mostly enriched for cell wall-related pathways; specifically, GA3 treatment elicited the expression of the cell wall-associated gene XYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASE 19 (SlXTH19), whose overexpression resulted in increased plant height. Comparative analyses revealed that SlXTH19-overexpressing lines exhibited larger cell dimensions and increased XTH activity, along with higher contents of lignin, cellulose, and hemicellulose, thereby underscoring the gene's role in maintaining cell wall integrity. Conversely, treatments with ethephon (ETH) and 1-Naphthaleneacetic acid (NAA) led to suppressed plant height and reduced SlXTH19 expression. Collectively, these findings illuminate a competitive interplay between GA and ethylene/auxin signaling pathways in regulating cell wall remodeling via SlXTH19 activation, ultimately influencing tomato plant height.

Osmanthus fragrans is an ethylene-sensitive flower, and flower senescence was mediated by ethylene-responsive transcription factors (OfERFs). A total of 227 OfERFs were identified from O. fragrans, which were classified into five subfamilies: AP2 (35), DREB (57), ERF (125), RAV (6), and Soloist (4). Gene composition and structural analysis indicate that members of different subfamilies have different gene structures and conserved domains. Their gene promoter contains various functional responsive elements, including auxin, jasmonic acid, and other responsive elements. Among them, 124 OfAP2/ERF genes have expressed at any stage of flowering, and 10 of them may play roles in flowering or senescence. By comparative transcriptome analysis, OfAP2/ERFs affected by ethephon (ETH) and 5'-azacytidine (Aza) treatment were divided into three categories, which have various target gene sets. Importantly, these target gene sets participate in similar or different biological processes and metabolic pathways, suggesting that ethylene and DNA hypomethylation have crosstalk and a unique mechanism in regulating the flower senescence of O. fragrans. Co-expression analysis revealed that several key OfAP2/ERFs played a central role in organic acid metabolism and biosynthesis of branched-chain amino acids (BcAAs), among which OfERF017 was selected for further functional analysis. Overexpression of OfERF017 leads to significant enrichment of genes in organic acid metabolism pathways, which leads to a decrease in organic acid levels and promoting the flower senescence of O. fragrans. Together, these results give insights into the characteristics and functional analysis of OfAP2/ERF genes in O. fragrans.

Beneficial fungi of the genus Trichoderma are among the most widespread biocontrol agents that induce a plant’s defense response against pathogens. Fusarium solani is one of the main pathogens that can negatively affect Astragalus mongholicus production and quality. To investigate the impact of Trichoderma harzianum on Astragalus mongholicus defense responses to Fusarium solani, A. mongholicus roots under T. harzianum + F. solani (T + F) treatment and F. solani (F) treatment were sampled and subjected to transcriptomic analysis. A differential expression analysis revealed that 6361 differentially expressed genes (DEGs) responded to T. harzianum induction. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the 6361 DEGs revealed that the genes significantly clustered into resistance-related pathways, such as the plant–pathogen interaction pathway, phenylpropanoid biosynthesis pathway, flavonoid biosynthesis pathway, isoflavonoid biosynthesis pathway, mitogen-activated protein kinase (MAPK) signaling pathway, and plant hormone signal transduction pathway. Pathway analysis revealed that the PR1, formononetin biosynthesis, biochanin A biosynthesis, and CHIB, ROS production, and HSP90 may be upregulated by T. harzianum and play important roles in disease resistance. Our study further revealed that the H2O2 content was significantly increased by T. harzianum induction. Formononetin and biochanin A had the potential to suppress F. solani. Weighted gene coexpression network analysis (WGCNA) revealed one module, including 58 DEGs associated with T. harzianum induction. One core hub gene, RPS25, was found to be upregulated by T. harzianum, SA (salicylic acid) and ETH (ethephon). Overall, our data indicate that T. harzianum can induce induced systemic resistance (ISR) and systemic acquired resistance (SAR) in A. mongholicus. The results of this study lay a foundation for a further understanding of the molecular mechanism by which T. harzianum induces resistance in A. mongholicus.

Chemical regulation has beneficial effects on the growth, yield, and fiber quality of cotton with different plant architectures. This study aimed to investigate the combined effects of chemical regulators such as mepiquat chloride (1,1-dimethyl-piperidiniuchloride, DPC), chlormequat chloride (CCC), thidiazuron (TDZ), and ethephon (ETH) during the growth period of cotton. Different combinations of chemical regulators were applied to examine the growth, development, yield, and quality of cotton. The results showed that the application of different chemical regulators had varying effects on the yields of the two cotton varieties with distinct plant architecture. Specifically, K1C1 (before and after topping with 1:1 25% DPC, 50% TDZ, and 40% ETH) and K2C2 (before topping with 25% DPC and after topping with 50% CCC, 50% TDZ, and 40% ETH) were sprayed on ‘Wankemian-1’ and ‘Wanmian-191’, thereby increasing the cotton yield. The K2C2 treatment increased the upper half mean length and fiber strength of the two varieties but decreased the fiber length uniformity index. The fiber strength, fiber length uniformity index, and spinning consistency index of ‘Wankemian-1’ were higher than those of ‘Wanmian-191’. Based on comprehensive yield, quality, and economic benefits, K1C1 and K2C2 were determined to be the most effective chemical regulators of ‘Wankemian-1’ and ‘Wanmian-191’, respectively.

Varying concentrations of ethephon induce antioxidant defences and cell wall degradation to regulate storage quality of fresh-cut lotus root

Aluminium-based metal-organic frameworks for the colorimetric ethephon detection in fruit by paper microsensor

Elucidating the molecular mechanisms in phytohormones-induced alleviation of postharvest physiological deterioration in cassava tuberous roots

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

Ethephon (ETH) is widely used to promote fruit ripening and improve fruit quality. However, improper use is harmful to human health and to the environmental safety. Therefore, development of the techniques for on-site and at real-time monitoring of ETH is of importance for its safe use. In this work, we developed a nanofilm-based fluorescence film sensor (FFS) and realized highly efficient detection of ETH in vapor phase, where the detection limit (DL) is <0.2 ppb, the response time is less than 10 s, and the interference is almost free. The unusual sensing performance of the sensor was ascribed to the specific binding of the nanofilm to ETH and to its great porosity, which enables efficient adlayer mass transfer, a requirement for high signal-to-noise ratio. Moreover, visualization-based qualitative sensing is also realized. The nanofilm, a key component of the sensor, was prepared at the humid air/DMSO interface. The building blocks used were a specially designed fluorescent o-carborane derivative (CB-2CHO) and a cross-linker BTN possessing three acylhydrazine groups. The nanofilm as prepared is flexible, uniform, thickness tunable, and photochemically super stable. We believe our effort not only addresses the challenging issue of on-site and at real-time detection of ETH but also provides another route for developing new FFSs via sensing film innovation.