BACKGROUND: Astragaloside IV is a main medicinal active ingredient in Astragalus membranaceus Bge. var. mongholicus (Bge.) Hsiao, which is also the key biomarker of A. membranaceus quality. Ethylene has been well-documented to involve in secondary metabolites biosynthesis in plants. Nevertheless, how ethylene regulates astragaloside IV biosynthesis in A. membranaceus is still unclear. Therefore, in the present study different dosages and time-dependent exogenous application of ethephon (Eth) were employed to analyze astragaloside IV accumulation and its biosynthesis genes expression level in hydroponically A. membranaceus.
RESULTS: Exogenous 200 µmol·L- 1Eth supply is most significantly increased astragaloside IV contents in A. membranaceus when compared with non-Eth supply. After 12 h 200 µmol·L- 1 Eth treatment, the astragaloside IV contents reaching the highest content at 3 d Eth treatment(P ≤ 0.05). Moreover, After Eth treatment, all detected key genes involved in astragaloside IV synthesis were significant decrease at 3rd day(P ≤ 0.05). However, SE displayed a significant increase at the 3rd day under Eth treatment(P ≤ 0.05). Under Eth treatment, the expression level of FPS, HMGR, IDI, SS, and CYP93E3 exhibited significant negative correlations with astragaloside IV content, while expression level of SE displayed a significant positive correlation.
CONCLUSIONS: These findings suggest that exogenous Eth treatment can influence the synthesis of astragaloside IV by regulating the expression of FPS, HMGR, IDI, SS, CYP93E3 and SE. This study provides a theoretical basis for utilizing molecular strategies to enhance the quality of A. membranaceus.

Ethylene plays diverse roles in post-harvest processes of horticultural crops. However, its impact and regulation mechanism on the postharvest physiological deterioration (PPD) of cassava storage roots is unknown. In this study, a notable delay in PPD of cassava storage roots was observed when ethephon was utilized as an ethylene source. Physiological analyses and quantitative acetylproteomes were employed to investigate the regulation mechanism regulating cassava PPD under ethephon treatment. Ethephon was found to enhance the reactive oxygen species (ROS) scavenging system, resulting in a significant decrease in H2O2 and malondialdehyde (MDA) content. The comprehensive acetylome analysis identified 12,095 acetylation sites on 4403 proteins. Subsequent analysis demonstrated that ethephon can regulate the acetylation levels of antioxidant enzymes and members of the energy metabolism pathways. In summary, ethephon could enhance the antioxidant properties and regulate energy metabolism pathways, leading to the delayed PPD of cassava.

BACKGROUND: Blueberry fruit exhibit atypical climacteric ripening with a non-auto-catalytic increase in ethylene coincident with initiation of ripening. Further, application of ethephon, an ethylene-releasing plant growth regulator, accelerates ripening by increasing the proportion of ripe (blue) fruit as compared to the control treatment. To investigate the mechanistic role of ethylene in regulating blueberry ripening, we performed transcriptome analysis on fruit treated with ethephon, an ethylene-releasing plant growth regulator.
RESULTS: RNA-Sequencing was performed on two sets of rabbiteye blueberry (\'Powderblue\') fruit: (1) fruit from divergent developmental stages; and (2) fruit treated with ethephon, an ethylene-releasing compound. Differentially expressed genes (DEGs) from divergent developmental stages clustered into nine groups, among which cluster 1 displayed reduction in expression during ripening initiation and was enriched with photosynthesis related genes, while cluster 7 displayed increased expression during ripening and was enriched with aromatic-amino acid family catabolism genes, suggesting stimulation of anthocyanin biosynthesis. More DEGs were apparent at 1 day after ethephon treatment suggesting its early influence during ripening initiation. Overall, a higher number of genes were downregulated in response to ethylene. Many of these overlapped with cluster 1 genes, indicating that ethylene-mediated downregulation of photosynthesis is an important developmental event during the ripening transition. Analyses of DEGs in response to ethylene also indicated interplay among phytohormones. Ethylene positively regulated abscisic acid (ABA), negatively regulated jasmonates (JAs), and influenced auxin (IAA) metabolism and signaling genes. Phytohormone quantification supported these effects of ethylene, indicating coordination of blueberry fruit ripening by ethylene.
CONCLUSIONS: This study provides insights into the role of ethylene in blueberry fruit ripening. Ethylene initiates blueberry ripening by downregulating photosynthesis-related genes. Also, ethylene regulates phytohormone-metabolism and signaling related genes, increases ABA, and decreases JA concentrations. Together, these results indicate that interplay among multiple phytohormones regulates the progression of ripening, and that ethylene is an important coordinator of such interactions during blueberry fruit ripening.

暂无摘要。

Nutrient leaching is a major reason for fresh and ground water contamination. Menthol is the major bioactive ingredient of Mentha arvensis L. and one of the most traded products of global essential oil market. The indigenous production of menthol crystals in developing countries of the world can prove to be the backbone for local growers and poor farmers. Therefore, present research was designed to check the effects of nano-structured plant growth regulators (PGRs) (28-homobrassinolide and ethephon) with reduced leaching potentials on the essential oil and menthol (%) of Mentha arvensis L. The prepared nano-formulations were characterized by Fourier transform infrared (FTIR) spectroscopy, Laser induced breakdown spectroscopy (LIBS), Differential scanning colorimetry-thermal gravimetric analysis (DSC-TGA), Scanning electron microscopy (SEM), Atomic absorption spectrometry (AAS) and Zeta potential and Zeta size analysis. The menthol (%) was determined by modified spectrophotometric and gas chromatographic (GC) method. The highest essential oil (%) was obtained by the application of 28-homobrassinolide-Zn-NPs-L-II (0.92 ± 0.09%) and ethephon-Ca-NPs-L-III (0.91 ± 0.05%) as compared to the control (0.65 ± 0.03%) and blank (0.62 ± 0.09%). The highest menthol (%) was obtained by applying 28-homobrassinolide-Ca-NPs-L-I (80.06 ± 0.07%), 28-homobrassinolide-Ca-NPs-L-II (80.48 ± 0.09%) and 28-homobrassinolide-Ca-NPs-L-III (80.84 ± 0.11%) and ethephon-Ca-NPs-L-III (81.53 ± 0.17%) and ethephon-Zn-NPs-L-II (81.93 ± 0.26%) as compared to control (67.19 ± 0.14%) and blank (63.93 ± 0.17%).

Zoysia japonica (Zoysia japonica Steud.) is a kind of warm-season turfgrass with many excellent characteristics. However, the shorter green period and longer dormancy caused by cold stress in late autumn and winter are the most limiting factors affecting its application. A previous transcriptome analysis revealed that ethephon regulated genes in chlorophyll metabolism in Zoysia japonica under cold stress. Further experimental data are necessary to understand the effect and underlying mechanism of ethephon in regulating the cold tolerance of Zoysia japonica. The aim of this study was to evaluate the effects of ethephon by measuring the enzyme activity, intermediates content, and gene expression related to ethylene biosynthesis, signaling, and chlorophyll metabolism. In addition, the ethylene production rate, chlorophyll content, and chlorophyll a/b ratio were analyzed. The results showed that ethephon application in a proper concentration inhibited endogenous ethylene biosynthesis, but eventually promoted the ethylene production rate due to its ethylene-releasing nature. Ethephon could promote chlorophyll content and improve plant growth in Zoysia japonica under cold-stressed conditions. In conclusion, ethephon plays a positive role in releasing ethylene and maintaining the chlorophyll content in Zoysia japonica both under non-stressed and cold-stressed conditions.

Sweet osmanthus (Osmanthus fragrans) is an ornamental evergreen tree species in China, whose flowers are sensitive to ethylene. The synthesis of ethylene is controlled by key enzymes and restriction enzymes, 1-aminocyclopropane-1-carboxylic acid synthase (ACS) and 1-aminocyclopropane-1-carboxylic acid oxidase (ACO), which are encoded by multigene families. However, the key synthase responsible for ethylene regulation in O. fragrans is still unknown.
This study aims to screen the key ethylene synthase genes of sweet osmanthus flowers in response to ethylene regulation.
In this study, we used the ACO and ACS sequences of Arabidopsis thaliana to search for homologous genes in the O. fragrans petal transcriptome database. These genes were also analyzed bioinformatically. Finally, the expression levels of O. fragrans were compared before and after senescence, as well as after ethephon and silver nitrate treatments.
The results showed that there are five ACO genes and one ACS gene in O. fragrans transcriptome database, and the phylogenetic tree revealed that the proteins encoded by these genes had high homology to the ACS and ACO proteins in plants. Sequence alignment shows that the OfACO1-5 proteins have the 2OG-Fe(II) oxygenase domain, while OfACS1 contains seven conserved domains, as well as conserved amino acids in transaminases and glutamate residues related to substrate specificity. Expression analysis revealed that the expression levels of OfACS1 and OfACO1-5 were significantly higher at the early senescence stage compared to the full flowering stage. The transcripts of the OfACS1, OfACO2, and OfACO5 genes were upregulated by treatment with ethephon. However, out of these three genes, only OfACO2 was significantly downregulated by treatment with AgNO3.
Our study found that OfACO2 is an important synthase gene in response to ethylene regulation in sweet osmanthus, which would provide valuable data for further investigation into the mechanisms of ethylene-induced senescence in sweet osmanthus flowers.

BACKGROUND: Papaya (Carica papaya) is an economically important fruit cultivated in the tropical and subtropical regions of China. However, the rapid softening rate after postharvest leads to a short shelf-life and considerable economic losses. Accordingly, understanding the mechanisms underlying fruit postharvest softening will be a reasonable way to maintain fruit quality and extend its shelf-life.
RESULTS: Mitogen-activated protein kinases (MAPKs) are conserved and play essential roles in response to biotic and abiotic stresses. However, the MAPK family remain poorly studied in papaya. Here, a total of nine putative CpMAPK members were identified within papaya genome, and a comprehensive genome-wide characterization of the CpMAPKs was performed, including evolutionary relationships, conserved domains, gene structures, chromosomal locations, cis-regulatory elements and expression profiles in response to phytohormone and antioxidant organic compound treatments during fruit postharvest ripening. Our findings showed that nearly all CpMAPKs harbored the conserved P-loop, C-loop and activation loop domains. Phylogenetic analysis showed that CpMAPK members could be categorized into four groups (A-D), with the members within the same groups displaying high similarity in protein domains and intron-exon organizations. Moreover, a number of cis-acting elements related to hormone signaling, circadian rhythm, or low-temperature stresses were identified in the promoters of CpMAPKs. Notably, gene expression profiles demonstrated that CpMAPKs exhibited various responses to 2-chloroethylphosphonic acid (ethephon), 1-methylcyclopropene (1-MCP) and the combined ascorbic acid (AsA) and chitosan (CTS) treatments during papaya postharvest ripening. Among them, both CpMAPK9 and CpMAPK20 displayed significant induction in papaya flesh by ethephon treatment, and were pronounced inhibition after AsA and CTS treatments at 16 d compared to those of natural ripening control, suggesting that they potentially involve in fruit postharvest ripening through ethylene signaling pathway or modulating cell wall metabolism.
CONCLUSIONS: This study will provide some valuable insights into future functional characterization of CpMAPKs, and hold great potential for further understanding the molecular mechanisms underlying papaya fruit postharvest ripening.

A major portion of maize is produced under rainfed conditions in the tropics with relatively poor yield because of the unpredictable and irregular distribution of seasonal rainfall, as well as a decline in pre-rainy season rainfall due to climate change, so identification of sustainable production options is utmost needed. Thus, the present studies were conducted in a greenhouse (GH) to ascertain the water stress-tolerant traits of maize and at the field level in the tropical environment of Thailand to see the stimulating possibility of the ascertained traits in a locally popular cultivar using ethephon. Depending on tolerance level, three maize genotypes (Suwan 2301 > Suwan 4452 > S 7328) were tested under different water conditions-well-watered, short-term, and long-term water stress-in the GH. At the field level, the locally popular maize cultivar Suwan 5819 was examined with six ethephon levels (doses in g a.i. ha-1 of ethephon, i.e., T1, 281 at V6 stage; T2, 281 at V6 + 281 at V10 stage; T3, 281 at V10 stage; T4, 562 at V6 stage; T5, 562 at V6 + 562 at V10 stage; T6, 562 at V10 stage) against no ethephon application (T0) under rainfed conditions. Maize suffered from the scarcity of sufficient rainfall during 26-39 days after planting (DAP) and 43-63 DAP in the field. The yield index (YI) was identified from biplot analysis as one of the suitable standards for drought tolerance checks for maize at GH as well as at field level in the tropics. The YI value of observed agro-physio-biochemical traits of maize in GH showed that relative water content (RWC, 1.23), stem base diameter (SBD, 1.21), total soluble sugar (TSS, 1.15), proline (Pr, 1.13), aboveground plant biomass (APB, 1.13), root weight (RW, 1.13), relative growth rate (RGR, 1.15), specific leaf weight (SLW, 1.12), and net assimilation rate (NAR, 1.08) were the most desirable. Efforts were made to stimulate these traits under water stress at the field level. Ethephon application as T1 helped to gain higher kernel yield (KY) (5.26 t ha-1) with the support of higher RWC (90.38%), proline (24.79 µmol g-1 FW), TSS (1629 mg g-1 FW), SBD (24.49 mm), APB (271.34 g plant-1), SLW (51.71 g m-2), RGR (25.26 mg plant-1 day-1), and NAR (0.91 mg cm-2 day-1) compared to others, especially no ethephon application. Furthermore, the attributes SLW, SBD, Pr, heat utilization efficiency (HUE), 100-kernel weight, TSS, electrolyte leakage, and lodging percentage showed a substantial direct effect and significant correlation with KY. Aside from higher KY, ethephon application as T1 tactics resulted in higher values of energy efficiency (1.66), HUE (2.99 kg ha-1 °C days-1), gross margin (682.02 USD ha-1), MBCR (3.32), and C absorption (6.19 t C ha-1), indicating that this practice may be a good option for maize sustainable production under rainfed conditions.

Ethephon (ETH) is a common pesticide, and its overuse has resulted in a variety of health problems for humans. However, the existing ETH detection methods are tedious and time-consuming, and real-time ETH identification remains a significant difficulty. To mitigate this concern, a dual-emission ratiometric fluorescent probe Ru@ZrMOF was rationally synthesized for the detection of ETH. In the presence of ETH, the emission peak at 435 nm gradually increased, while the peak at 600 nm remained constant, accompanied by the fluorescence color change from red, pink, blue-violet to blue. The fluorescence intensity ratio (F435/F600) demonstrated two linear relations with the ETH concentration ranges at 3 - 50 μM and 50 - 500 μM, with a lowest detection limit at 1 μM. This was attributed to the formation of Zr-O-P bonds which attenuated the ligand-metal charge transfer (LMCT) process, resulting in the recovery of blue fluorescence of the ligand 2-Aminoterephthalic acid (2-APDC). To validate the practical application of the developed platform, a YOLO v5x-based WeChat applet \"96 Speckles\" was developed, and a 96-well plate and smartphone-embedded 3D-printed portable toolbox was designed for the real-time intelligent detection of ETH. This smart platform allows for real-time and efficient ETH analysis in various real samples including apples, pears and tomatoes.