RESUMEN
Bell pepper (Capsicum annuum L.) is a tradable and desirable crop; however, its perishable nature requires low-temperature handling. Paradoxically, cold causes chilling injury (CI) and post-harvest waste. Current knowledge about CI in pepper is limited. The mechanism of CI is multi-faceted; therefore, we focused on fatty acid (FA) desaturation. We identified an upstream nuclear transcription factor (TF), CaMYB340, belonging to the R2R3 MYB subfamily, that negatively regulates FA desaturation and CaCBF3 expression and whose gene and protein expression is induced by low temperature (4°C). Specifically, McrBC treatment and bisulfite sequencing PCR indicate that exposure to cold triggers DNA methylation on one of the CHH sites in the CaMYB340 promoter. This epigenetic event at least partly contributes to the upregulation of CaMYB340 transcript levels. Increased expression of CaMYB340 results in the formation of protein complexes with CabHLH93 and CaMYB1R1, which in turn downregulate the expression of downstream genes. For peppers held at low temperature, transient overexpression of CaMYB340 reduced unsaturated FA content and membrane fluidity, resulting in cold-induced poor peel texture. Transient CaMYB340 silencing increased FA desaturation and lowered electrolyte leakage, enhancing cold tolerance in CaMYB340 knockdown fruits. Overall, these results underscore the intricacy of transcriptional networks in plants and highlight the role of CaMYB340 in CI occurrence in pepper fruits.
Asunto(s)
Capsicum , Capsicum/metabolismo , Frío , Ácidos Grasos Insaturados/metabolismo , Frutas/genética , Frutas/metabolismo , Regulación de la Expresión Génica de las Plantas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
The combinational effects of kojic acid and lauroyl arginine ethyl ester hydrochloride (ELAH) on fresh-cut potatoes were investigated. Kojic acid of 0.6% (w/w) effectively inhibited the browning of fresh-cut potatoes and displayed antimicrobial capacity. The color difference value of samples was decreased from 175 to 26 by kojic acid. In contrast, ELAH could not effectively bind with the active sites of tyrosinase and catechol oxidase at molecular level. Although 0.5% (w/w) of ELAH prominently inhibited the microbial growth, it promoted the browning of samples. However, combining kojic acid and ELAH effectively inhibited the browning of samples and microbial growth during the storage and the color difference value of samples was decreased to 52. This amount of kojic acid inhibited enzyme activities toward phenolic compounds. The results indicated that combination of kojic acid and ELAH could provide a potential strategy to extend the shelf life of fresh-cut products.
Asunto(s)
Arginina , Monofenol Monooxigenasa , Pironas , Solanum tuberosum , Pironas/farmacología , Pironas/química , Arginina/química , Arginina/análogos & derivados , Arginina/farmacología , Solanum tuberosum/química , Solanum tuberosum/crecimiento & desarrollo , Monofenol Monooxigenasa/metabolismo , Conservación de Alimentos/métodos , Catecol Oxidasa/metabolismo , Conservantes de Alimentos/farmacología , Conservantes de Alimentos/química , Bacterias/efectos de los fármacos , Bacterias/genéticaRESUMEN
Physical exercises can improve individuals' physical health and cognition, but the internal influence path is unclear. This study aims to examine the influence of pom cheerleading training on physical fitness and executive function of preschool children and explore the relationship between sports training, physical fitness, and executive function. We selected seventy-one preschool children and divided them into the experimental group (n = 36) and the control group (n = 35). The experimental group kept a 12-week pom cheerleading training, and the exercises of the control group remained normal. Children's physical fitness and executive function were tested, in one week before and after the experiment, respectively. Results of repeated measurements analysis of variance and structural equation model test showed: (1) after 12-week pom cheerleading training, in terms of physical fitness, the experimental group has a significant improvement over the control group on agility and speed; in terms of executive function, the inhibitory control and working memory of the experimental group were significantly enhanced over the control group. (2) Speed quality plays a partial mediating role between pom cheerleading training and inhibitory control; agility plays a major mediating role between pom cheerleading training and working memory. It is concluded that physical exercise can directly improve preschool children's executive function, and indirectly enhance executive function mediated by physical fitness. Furthermore, structured and systematic physical education should be adopted for preschool children to cultivate their interest in sports and enhance their cognition.
Asunto(s)
Función Ejecutiva , Aptitud Física , Humanos , Preescolar , Ejercicio Físico , Cognición , Terapia por EjercicioRESUMEN
Cold-stored 'Nanguo' pears are susceptible to peel browning during subsequent shelf life. In this study, 'Nanguo' pears were cold-stored for different periods to elucidate the metabolism of phenylpropanoid accompanying browning. Changes in phenolics and flavonoids and the crucial enzyme activity and related gene expression involved in the phenylpropanoid pathway were monitored. It was found that the fruit that underwent long-term storage showed peel browning symptoms prior to softening, and the symptom got worse with increasing shelf life. Meanwhile, the accumulation of reactive oxygen species (ROS) and the decrease of ROS scavenging ability were noted. The content of phenolics and flavonoids and the activity and expression of shikimate dehydrogenase (SKDH), phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), and 4-coumarate-CoA ligase (4CL) involved in the phenylpropanoid pathway decreased with prolonged storage. Correlation analysis revealed that browning was positively correlated with ROS accumulation, and the content of phenolics and flavonoids directly affected ROS scavenging ability. In addition, the decrease in phenolics and flavonoids might be owing to the reduced activity of SKDH, PAL, and 4CL and the down-regulated expression of PuPAL and Pu4CL. Collectively, this study indicated that the metabolism of phenylpropanoid is associated with the browning response induced by low-temperature stress.
Asunto(s)
Pyrus , Frío , Flavonoides/metabolismo , Frutas/genética , Fenoles/metabolismo , Fenilanina Amoníaco-Liasa/genética , Fenilanina Amoníaco-Liasa/metabolismo , Pyrus/genética , Especies Reactivas de Oxígeno/metabolismoRESUMEN
We investigated the effect of exogenous glutathione (GSH) on chilling injury (CI) in postharvest bell pepper fruits stored at low temperature and explored the mechanism of this treatment from the perspective of the ascorbate-glutathione (AsA-GSH) cycle. Compared with the control, fruits treated with exogenous GSH before refrigeration displayed only slight CI symptoms and mitigated CI-induced cell damage after 10 d. Moreover, the treated peppers had lower lipid peroxidation product, H2O2, and O2- content than those did the control. Glutathione treatment enhanced the ascorbate-glutathione cycle by upregulating CaAPX1, CaGR2, CaMDHAR1, and CaDHAR1 and the antioxidant enzymes APX, GR, and MDHAR associated with the ascorbate-glutathione cycle. Glutathione treatment also increased ascorbate and glutathione concentrations. Taken together, our results showed that exogenous GSH treatment could alleviate CI in pepper fruits during cold storage by triggering the AsA-GSH cycle and improving antioxidant capacity.
Asunto(s)
Ácido Ascórbico/metabolismo , Capsicum/efectos de los fármacos , Capsicum/metabolismo , Frío , Glutatión/farmacología , Frutas/efectos de los fármacos , Frutas/metabolismo , Glutatión/metabolismo , Peróxido de Hidrógeno/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Plantones/efectos de los fármacos , Plantones/metabolismoRESUMEN
'Nanguo' pear is particularly renowned for its fragrance. Esters are the main components of its aroma, which are synthesized primarily by the LOX pathway. We identified the main volatile esters and critical gene family members involved in the LOX pathway by monitoring their variation accompanying post-harvest ripening and examining their roles through principal component analysis (PCA), partial least-square regression (PLSR), and correlation analysis. In pears ripening to the optimum taste period (OTP), components and contents of volatile esters reached a peak, of which ethyl butanoate, ethyl hexanoate, and hexyl acetate were most prominent. Linoleic acid and linolenic acid contents rose greatly until OTP and then declined; the activities of LOX, alcohol dehydrogenase (ADH), and alcohol acyltransferase (AAT) increased progressively until the OTP. Among the genes involved in LOX-pathway, the expressions of PuLOX3, PuADH3, and PuAAT contributed most to changes of total ester and main esters in 'Nanguo' pears.
Asunto(s)
Frutas/fisiología , Lipooxigenasa/metabolismo , Odorantes/análisis , Proteínas de Plantas/genética , Pyrus/fisiología , Aciltransferasas , Alcohol Deshidrogenasa/genética , Alcohol Deshidrogenasa/metabolismo , Caproatos/análisis , Caproatos/metabolismo , Ésteres/análisis , Ésteres/metabolismo , Almacenamiento de Alimentos , Frutas/genética , Frutas/metabolismo , Regulación de la Expresión Génica de las Plantas , Análisis de los Mínimos Cuadrados , Ácido Linoleico/análisis , Ácido Linoleico/genética , Ácido Linoleico/metabolismo , Lipooxigenasa/genética , Proteínas de Plantas/metabolismo , Análisis de Componente Principal , Pyrus/genética , Pyrus/metabolismo , Compuestos Orgánicos Volátiles/análisis , Ácido alfa-Linolénico/metabolismoRESUMEN
The effect of glycine betaine (GB) on chilling injury (CI)-induced pericarp browning in 'Nanguo' pears was investigated during shelf life at 20⯰C after storage at 0⯰C for 120â¯d. GB treatment alleviated the severity of browning in 'Nanguo' pears as represented by lower browning index (BI) and browning incidence. Membrane lipid peroxidation in GB-treated fruit was lower than that in the control, and membrane integrity was maintained in good condition. The activities and expression of ascorbate peroxidase (APX), catalase (CAT), and superoxide dismutase (SOD) were higher in GB-treated fruit than in control fruit. Furthermore, significantly higher proline content, proline synthesis key enzyme activities, and gene expression were observed in the treated fruit, including ornithine d-aminotransferase (OAT) and Δ1-pyrroline-5-carbox-ylate synthetase (P5CS), which were consistent with the browning tendency. In a nutshell, GB treatment can effectively alleviate pericarp browning of cold-stored 'Nanguo' pears by regulating antioxidant enzymes and proline metabolism.
Asunto(s)
Betaína/farmacología , Glicina/farmacología , Pyrus/metabolismo , Antioxidantes/metabolismo , Catalasa/metabolismo , Frío , Frutas/metabolismo , Peroxidasa/metabolismo , Prolina/metabolismo , Pyrus/efectos de los fármacos , Superóxido Dismutasa/metabolismoRESUMEN
Chilling injury (CI) restricts the quality and shelf life of bell pepper fruits; reducing these CI-induced detrimental effects is therefore of high economic and agricultural relevance. Here, we investigated the effects of trisodium phosphate (TSP), salicylic acid (SA), and TSP + SA treatments on pepper fruits under cold stress at 4 °C for 25 d. Combined TSP + SA treatment performed an optimal effect. Specifically, TSP + SA treatment enhanced fatty-acid desaturation efficiency, as indicated by the increased expression of key fatty acid desaturase genes, and higher content of unsaturated fatty acids. Meanwhile, TSP + SA treatment inhibited the CI-induced membrane damage, manifested as lower electrolyte leakage and malondialdehyde content. Furthermore, low field-nuclear magnetic resonance and proline content also revealed that TSP + SA treatment mitigated CI through enhancing water retention in pepper fruits. Collectively, our results may shed new light on optimizing the low-temperature storage conditions of post-harvest peppers.
Asunto(s)
Capsicum/química , Ácidos Grasos/química , Fosfatos/química , Ácido Salicílico/química , Agua/química , Capsicum/efectos de los fármacos , Capsicum/metabolismo , Pared Celular/efectos de los fármacos , Frío , Ácidos Grasos/metabolismo , Frutas/química , Frutas/efectos de los fármacos , Frutas/metabolismo , Malondialdehído/química , Malondialdehído/metabolismo , Permeabilidad/efectos de los fármacos , Fosfatos/farmacología , Prolina/química , Ácido Salicílico/farmacologíaRESUMEN
Refrigeration is commonly used to extend the storage life of "Nanguo" pears, but fruit in long-term refrigeration is prone to peel browning, which is related to membrane lipid degradation. To determine the mechanism of membrane lipid degradation, we identified two R2R3-MYB transcription factors (TFs), PuMYB21 and PuMYB54, from "Nanguo" pears, which were notably expressed in response to cold stress and during the peel-browning process. The results from yeast one-hybrid, electrophoretic mobility shift, and transient expression assays indicated that both PuMYB21 and PuMYB54 directly bind to the promoter of PuPLDß1 (a key enzyme catalyzing the hydrolysis of membrane phospholipids) and activate its expression, which probably enhances the degradation of membrane phospholipids and eventually results in peel browning. Moreover, the overexpression of PuMYB21 and PuMYB54 can greatly activate the transcription of endogenous PuPLDß1 in both "Nanguo" pear fruits and calli, and their silencing can inhibit its transcription. Furthermore, yeast two-hybrid, bimolecular fluorescence complementation, and pull-down assays verified that PuMYB21 interacts with PuMYB54 to enhance the expression of PuPLDß1. In summary, we demonstrate that PuMYB21 and PuMYB54 may have roles in membrane lipid metabolism by directly binding to the downstream structural gene PuPLDß1 during the low temperature-induced peel browning of "Nanguo" pears.
RESUMEN
Bell peppers are susceptible to chilling injury (CI). To uncover the metabolism of membrane lipid fatty acids (FAs) accompanying CI, a gas chromatography-mass spectrometry (GC-MS)-based approach was used to quantitatively profile major membrane lipid FAs in bell peppers. RT-qPCR was performed to investigate the expression of the key genes that regulate the synthesis of unsaturated FAs. Additionally, we used microstructural, organoleptic, and physicochemical investigations to monitor the primary physiological metabolism of bell peppers. The study revealed that CI symptoms mostly resulted from the destabilization of the cytomembrane, which was induced by decreasing FA desaturation. Moreover, three times lower level of the double bond index in chilled fruits, than the control, further proved that membrane FA unsaturation can be considered a key factor during CI. In conclusion, this study revealed that the metabolism of membrane lipid FAs is involved in responses to CI.
Asunto(s)
Capsicum/metabolismo , Ácidos Grasos/metabolismo , Conservación de Alimentos/métodos , Lípidos de la Membrana/metabolismo , Capsicum/química , Capsicum/genética , Ácidos Grasos/análisis , Ácidos Grasos Insaturados/genética , Ácidos Grasos Insaturados/metabolismo , Frutas/química , Frutas/genética , Frutas/metabolismo , Cromatografía de Gases y Espectrometría de Masas , Regulación de la Expresión Génica de las Plantas , Lipooxigenasa/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , TemperaturaRESUMEN
The interconnect half-pitch size will reach ≈20 nm in the coming sub-5 nm technology node. Meanwhile, the TaN/Ta (barrier/liner) bilayer stack has to be >4 nm to ensure acceptable liner and diffusion barrier properties. Since TaN/Ta occupy a significant portion of the interconnect cross-section and they are much more resistive than Cu, the effective conductance of an ultrascaled interconnect will be compromised by the thick bilayer. Therefore, 2D layered materials have been explored as diffusion barrier alternatives. However, many of the proposed 2D barriers are prepared at too high temperatures to be compatible with the back-end-of-line (BEOL) technology. In addition, as important as the diffusion barrier properties, the liner properties of 2D materials must be evaluated, which has not yet been pursued. Here, a 2D layered tantalum sulfide (TaSx ) with ≈1.5 nm thickness is developed to replace the conventional TaN/Ta bilayer. The TaSx ultrathin film is industry-friendly, BEOL-compatible, and can be directly prepared on dielectrics. The results show superior barrier/liner properties of TaSx compared to the TaN/Ta bilayer. This single-stack material, serving as both a liner and a barrier, will enable continued scaling of interconnects beyond 5 nm node.