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2.
Plant Physiol Biochem ; 139: 630-641, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31039504

RESUMO

Melatonin, an evolutionarily conserved molecule, is implicated in numerous physiological processes in plants. To explore the potential roles of melatonin in response to UV-B radiation, we examined the influence of exogenous melatonin on Malus hupehensis Rehd. seedlings under two levels of UV-B radiation. Under UV-B stress, seedlings showed significant reduction in plant growth, biomass production, and root system development. However, 1 µM melatonin solution markedly alleviated these effects, especially at the higher dosage of UV-B radiation. The inhibitory effects of UV-B radiation on photosynthetic parameters, chlorophyll fluorescence parameters, stomatal apertures, chlorophyll levels and leaf membrane damages were also markedly alleviated with melatonin application. Melatonin treatment was also associated with higher activity and expression of genes encoding antioxidant enzymes (ascorbate peroxidase, catalase and peroxidase) and greater decline of H2O2 content in leaves exposed to UV-B. Moreover, exogenous melatonin treatment and UV-B stress increased the concentration of endogenous melatonin. The content of several phenolic compounds, including chlorogenic acid, phloridzin and quercetin-3-galactoside, also increased under UV-B stress, and these were further elevated significantly with melatonin addition. This study provides insight into the role(s) of endogenous melatonin in response to UV-B stress, and will facilitate application of exogenous melatonin in agriculture.


Assuntos
Malus/efeitos dos fármacos , Malus/metabolismo , Melatonina/farmacologia , Raios Ultravioleta , Antioxidantes/metabolismo , Clorofila/metabolismo , Peróxido de Hidrogênio/metabolismo , Malus/efeitos da radiação , Fenóis/metabolismo , Espécies Reativas de Oxigênio/metabolismo
3.
Biochem Biophys Res Commun ; 512(2): 381-386, 2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-30902392

RESUMO

The MYB transcription factors are important for many aspects of plant stress responses. In this study, we isolated and identified an apple MYB gene, MdMYB108L, whose expression is induced by light and cold stresses. An analysis of MdMYB108L-overexpressing transgenic apple calli revealed that MdMYB108L enhances cold tolerance in apple by upregulating MdCBF3 expression. Interestingly, the expression of MdHY5, which encodes an integrator of light and cold signals, was significantly downregulated in transgenic calli. Yeast one-hybrid and electrophoretic mobility shift assays indicated that MdMYB108L positively regulates cold tolerance by binding to the MdCBF3 promoter. Additionally, MdHY5 functions upstream of MdMYB108L, and the resulting increase in MdMYB108L abundance downregulates MdHY5 transcription. The results of this study elucidate a new pathway for the regulation of apple cold tolerance via a feedback mechanism involving MdMYB108L and MdHY5.


Assuntos
Malus/fisiologia , Proteínas de Plantas/fisiologia , Fatores de Transcrição/fisiologia , Aclimatação/genética , Aclimatação/fisiologia , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/fisiologia , Temperatura Baixa , Resposta ao Choque Frio/genética , Resposta ao Choque Frio/fisiologia , Retroalimentação Fisiológica , Regulação da Expressão Gênica de Plantas , Luz , Malus/genética , Malus/efeitos da radiação , Modelos Biológicos , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Transdução de Sinais , Fatores de Transcrição/genética
4.
Plant Cell Physiol ; 60(5): 1055-1066, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30715487

RESUMO

In many plants, anthocyanin biosynthesis is affected by environmental conditions. Ultraviolet-B (UV-B) radiation promotes anthocyanin accumulation and fruit coloration in apple skin, whereas high temperature suppresses these processes. In this study, we characterized a B-box transcription factor, MdCOL4, from 'Fuji' apple, and identified its role in anthocyanin biosynthesis by overexpressing its encoding gene in apple red callus. The expression of MdCOL4 was reduced by UV-B, but promoted by high temperature. We explored the regulatory relationship between heat shock transcription factors (HSFs) and MdCOL4, and found that MdHSF3b and MdHSF4a directly bound to the heat shock element cis-element of the MdCOL4 promoter. MdCOL4 interacted with MdHY5 to synergistically inhibit the expression of MdMYB1, and MdCOL4 directly bound to the promoters of MdANS and MdUFGT, which encode genes in the anthocyanin biosynthetic pathway, to suppress their expression. Our findings shed light on the molecular mechanism by which MdCOL4 suppresses anthocyanin accumulation in apple skin under UV-B and high temperature.


Assuntos
Frutas/metabolismo , Malus/metabolismo , Antocianinas/metabolismo , Frutas/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Temperatura Alta , Malus/efeitos da radiação , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/efeitos da radiação , Temperatura , Fatores de Transcrição/metabolismo , Raios Ultravioleta
5.
J Plant Physiol ; 233: 52-57, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30597476

RESUMO

With the increasing use of hailnets and decrease in light availability in the ripening period of apple fruit, insufficient light exposure often causes poor colouration viz anthocyanin synthesis on certain parts of the fruit and on certain fruit within the tree. The aim of this study was to investigate the potential of improving anthocyanin synthesis, in terms of fruit colouration, the major incentive for a consumer. Therefore, the reflective ground cover Lumilys® was spread between 'Braeburn Mariri Red' apple rows under a crystalline hailnet seven weeks prior to harvest and colour measured on 240 attached apple fruit. The reflective ground cover increased the reflected light by 1.6 to 3.9 times 1.0 m above ground. The improved light utilization led to an improved peel colouration, especially on the shaded side of the apple fruit and fruit in the lower inner part of the canopy, A coloured visualization from orange (high light intensity), yellow (medium) to green (low light intensity) as a result of the individual PAR measurements every 20 cm inside the canopy showed how the reflective mulch influences the light penetration into the different parts of the tree canopy.


Assuntos
Antocianinas/biossíntese , Luz , Malus/efeitos da radiação , Cor , Produção Agrícola/métodos , Frutas/crescimento & desenvolvimento , Frutas/normas , Malus/crescimento & desenvolvimento , Malus/metabolismo , Árvores/metabolismo , Árvores/efeitos da radiação
6.
Plant Mol Biol ; 99(1-2): 45-66, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30519825

RESUMO

KEY MESSAGE: Shoot bending, as an effective agronomic measure, has been widely used to promote flowering in 'Fuji' apple trees. Here, we examined the transcriptional responses of genes in 'Fuji' apple buds at different flowering stages under a shoot-bending treatment using RNA sequencing. A complex genetic crosstalk-regulated network, involving abscisic acid-related genes, starch metabolism and circadian rhythm-related genes, as well as stress response-related genes, was up-regulated by shoot bending, in which were contrbuted to apple flower bud formation in response to shoot-bending conditions. Flower induction plays an important role in the apple tree life cycle, but young trees produce fewer and inferior flower buds. Shoot bending, as an effective agronomic measure, has been widely used to promote flowering in 'Fuji' apple trees. However, little is known about the gene expression network patterns and molecular regulatory mechanisms caused by shoot bending during the induced flowering. Here, we examined the transcriptional responses of genes in 'Fuji' apple buds at different flowering stages under a shoot-bending treatment using RNA sequencing. A steady up-regulation of carbon metabolism-related genes led to relatively high levels of sucrose in early induced flowering stages and starch accumulation during shoot bending. Additionally, global gene expression profiling determined that cytokinin, indole-3-acetic acid, gibberellin synthesis and signalling-related genes were significantly regulated by shoot bending, contributing to cell division and differentiation, bud growth and flower induction. A complex genetic crosstalk-regulated network, involving abscisic acid-related genes, starch metabolism- and circadian rhythm-related genes, as well as stress response-related genes, was up-regulated by shoot bending. Additionally, some transcription factor family genes that were involved in sugar, abscisic acid and stress response signalling were significantly induced by shoot bending. These important flowering genes, which were mainly involved in photoperiod, age and autonomous pathways, were up-regulated by shoot bending. Thus, a complex genetic network of regulatory mechanisms involved in sugar, hormone and stress response signalling pathways may mediate the induction of apple tree flowering in response to shoot-bending conditions.


Assuntos
Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Malus/genética , Reguladores de Crescimento de Planta/metabolismo , Transdução de Sinais , Ácido Abscísico/metabolismo , Citocininas/metabolismo , Flores/genética , Flores/fisiologia , Flores/efeitos da radiação , Perfilação da Expressão Gênica , Giberelinas/metabolismo , Malus/fisiologia , Malus/efeitos da radiação , Fotoperíodo , Brotos de Planta/genética , Brotos de Planta/fisiologia , Brotos de Planta/efeitos da radiação , Estresse Fisiológico , Sacarose/metabolismo , Árvores
7.
Food Chem ; 274: 415-421, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30372959

RESUMO

Photodynamic treatment (PDT) is an innovative technology with non-thermal and environmentally sound merits, but the evaluation on the storage qualities of fresh produce was scarce. In this study, the effects of curcumin-based PDT on the quality of fresh-cut 'Fuji' apple slices during storage at 4 °C were investigated. The impacts on the survival of Escherichia coli, color and weight loss were examined under different curcumin concentrations, illumination time or incubation time. Curcumin-based photodynamic inactivation of E. coli on the surface of apple slices reached 0.95 log. Curcumin-based PDT was proven to prevent browning and weight loss. Additionally, PDT significantly reduced the activity of polyphenol oxidase and peroxidases to 48% and 51%, respectively. Moreover, there were few negative changes in total phenolic, ascorbic acid content and anti-oxidant activity of the treated apples. These results indicated that curcumin-based PDT was a viable and promising non-thermal technology to preserve the quality of fresh produce.


Assuntos
Curcumina/farmacologia , Qualidade dos Alimentos , Armazenamento de Alimentos , Malus/efeitos dos fármacos , Malus/efeitos da radiação , Cor , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Escherichia coli/efeitos da radiação , Malus/enzimologia , Malus/microbiologia , Fotoquimioterapia
8.
J Sci Food Agric ; 98(6): 2258-2266, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28981162

RESUMO

BACKGROUND: The objective of this paper was to demonstrate application of quality function deployment in analysing effects of high power ultrasound on quality properties of apple juices and nectars. In order to develop a quality function deployment model, joint with instrumental analysis of treated samples, a field survey was performed to identify consumer preferences towards quality characteristics of juices/nectar. RESULTS: Based on field research, the three most important characteristics were 'taste' and 'aroma' with 28.5% of relative absolute weight importance, followed by 'odour' (16.9%). The quality function deployment model showed that the top three 'quality scores' for apple juice were treatments with amplitude 90 µm, 9 min treatment time and sample temperature 40 °C; 60 µm, 9 min, 60 °C; and 90 µm, 6 min, 40 °C. For nectars, the top three were treatments 120 µm, 9 min, 20 °C; 60 µm, 9 min, 60 °C; and A2.16 60 µm, 9 min, 20 °C. CONCLUSION: This type of quality model enables a more complex measure of large scale of different quality parameters. Its simplicity should be understood as its practical advantage and, as such, this tool can be a part of design quality when using novel preservation technologies. © 2017 Society of Chemical Industry.


Assuntos
Manipulação de Alimentos/métodos , Sucos de Frutas e Vegetais/análise , Malus/química , Ultrassom/métodos , Cor , Comportamento do Consumidor , Sucos de Frutas e Vegetais/efeitos da radiação , Humanos , Malus/efeitos da radiação , Prunus persica/química , Prunus persica/efeitos da radiação , Ondas Ultrassônicas
9.
J Food Sci ; 82(12): 2944-2953, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29125619

RESUMO

Application of an aqueous two-phase system (ATPS) coupled with ultrasonic technology for the extraction of phloridzin from Malus micromalus Makino was evaluated and optimized by response surface methodology (RSM). The ethanol/ammonium sulfate ATPS was selected for detailed investigation, including the phase diagram, effect of phase composition and extract conditions on the partition of phloridzin, and the recycling of ammonium sulfate. In addition, the evaluation of extraction efficiency and the identification of phloridzin were investigated. The optimal partition coefficient (6.55) and recovery (92.86%) of phloridzin were obtained in a system composed of 35% ethanol (w/w) and 16% (NH4 )2 SO4 (w/w), 51:1 liquid-to-solid ratio, and extraction temperature of 36 °C. Comparing with the traditional solvent extraction with respective 35% and 80% ethanol, ultrasonic-assisted aqueous two-phase extraction (UAATPE) strategy had significant advantages with lower ethanol consumption, less impurity of sugar and protein, and higher extracting efficiency of phloridzin. Our result indicated that UAATPE was a valuable method for the extraction and preliminary purification of phloridzin from the fruit of Malus micromalus Makino, which has great potential in the deep processing of Malus micromalus Makino industry to increase these fruits' additional value and drive the local economic development.


Assuntos
Fracionamento Químico/métodos , Malus/química , Extratos Vegetais/isolamento & purificação , Ultrassom/métodos , Sulfato de Amônio/química , Fracionamento Químico/instrumentação , Etanol/química , Frutas/química , Malus/efeitos da radiação , Extratos Vegetais/análise
10.
J Plant Physiol ; 219: 81-90, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29040901

RESUMO

The aim of the study was to improve the effect of stratification of apple "Ligol" seeds by application of selected compounds, phytohormones, and physical methods For this purpose the seeds were stratified at 3°C in distilled water or in the presence of potassium nitrate (KNO3), ethephon (ET), carbon monoxide (CO), hydrogen peroxide (H2O2), a mixture of KNO3, ET, CO, H2O2, gibberellins (GA3), 6-benzylaminopurine (BAP), jasmonic acid (JA), salicylic acid (SA) and a mixture of SA, GA3, BAP, JA, nitric oxide (NO), hydrogen chloride (HCL). Arranged protocols included various durations and combinations of selected compounds and phytohormones as well as laser and red light, heat shock - 2h heat shock (45°C) and Pulsed Radio Frequency (PRF) were investigated by germination tests and the activity of selected enzymes, gas exchange and index of chlorophyll in leaves. The obtained results showed the possibility to shorten more effectively the time of the apple 'Ligol' dormancy removal by treatments of the stratified seeds at 3°C with different biological and physical methods Selected compounds and phytohormones acted collectively as a regulatory complex controlling the course of release from dormancy. Physical methods (PRF and heat shock) additionally contributed to dormancy breakage. Duration of phytohormones or compounds impacts during stratification should be prolonged to minimum 7days to assure more balanced conditions of the regulatory complex for the acceleration of dormancy a removal. The most beneficial results were obtained after seed stratification for 7days on filter paper moistened in KNO3+Etephon+CO+H2O2 at 3°C, and then on filter paper moistened in phytohormones (GA3+BAP+JA) till the end of seed germination (3°C). The application of this protocol could be a very useful tool in a shortening the apple breeding cycle since the period of removing dormancy was reduced by 38days in comparison to stratified in water. PRF has also the additive role in breaking dormancy of apple 'Ligol' seed. Positive effects of compounds and phytohormones applied during stratification remarkably accelerated the growth of developed from them seedlings. Further research is needed to optimize stratification methods with appropriate contents and concentrations of compounds and phytohormones combined with PRF exposure.


Assuntos
Malus/crescimento & desenvolvimento , Dormência de Plantas , Temperatura Alta , Lasers , Luz , Malus/efeitos da radiação , Dormência de Plantas/efeitos da radiação , Reguladores de Crescimento de Planta/metabolismo , Ondas de Rádio
11.
J Agric Food Chem ; 65(35): 7653-7660, 2017 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-28805053

RESUMO

The photoreactivity of plant activator benzo(1,2,3)thiadiazole-7-carbothioic acid S-methyl ester (BTH), commonly named acibenzolar-S-methyl, was studied on the surfaces of glass, paraffinic wax films, and apple leaves. Experiments were carried out in a solar simulator using pure and formulated BTH (BION). Surface photoproducts were identified using liquid chromatography coupled with electrospray ionization and high-resolution Orbitrap mass spectrometry, while volatile photoproducts were characterized using an online thermal desorption system coupled to a gas chromatography-mass spectrometry (GC-MS) system. Pure BTH degraded quickly on wax surfaces with a half-life of 5.0 ± 0.5 h, whereas photolysis of formulated BTH was 7 times slower (t1/2 = 36 ± 14 h). On the other hand, formulated BTH was found to photolyze quickly on detached apple leaves with a half-life of 2.8 h ± 0.4 h. This drastic difference in photoreactivity was attributed to the nature and spreading of the BTH deposit, as influenced by the surfactant and surface characteristics. Abiotic stress of irradiated apple leaf was also shown to produce OH radicals which might contribute to the enhanced photodegradability. Eight surface photoproducts were identified, whereas GC-MS analyses revealed the formation of gaseous dimethyl disulfide and methanethiol. The yield of dimethyl disulfide ranged between 1.5% and 12%, and a significant fraction of dimethyl disulfide produced was found to be absorbed by the leaf. This is the first study to report on the formation of volatile chemicals and OH radicals during agrochemical photolysis on plant surfaces. The developed experimental approach can provide valuable insights into the heterogeneous photoreactivity of sprayed agrochemicals and could help improve dissipation models.


Assuntos
Agroquímicos/química , Malus/efeitos dos fármacos , Folhas de Planta/efeitos da radiação , Tiadiazóis/química , Cromatografia Gasosa-Espectrometria de Massas , Malus/efeitos da radiação , Fotoquímica , Fotólise , Folhas de Planta/efeitos dos fármacos
12.
Sci Rep ; 7: 41236, 2017 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-28145449

RESUMO

Within the chloroplasts reactive oxygen species (ROS) are generated during photosynthesis and stressful conditions. Excessive ROS damages chloroplasts and reduces photosynthesis if not properly detoxified. In this current study, we document that chloroplasts produce melatonin, a recently-discovered plant antioxidant molecule. When N-acetylserotonin, a substrate for melatonin synthesis, was fed to purified chloroplasts, they produced melatonin in a dose-response manner. To further confirm this function of chloroplasts, the terminal enzyme for melatonin synthesis, N-acetylserotonin-O-methyltransferase (ASMT), was cloned from apple rootstock, Malus zumi. The in vivo fluorescence observations and Western blots confirmed MzASMT9 was localized in the chloroplasts. A study of enzyme kinetics revealed that the Km and Vmax of the purified recombinant MzASMT9 protein for melatonin synthesis were 500 µM and 12 pmol/min·mg protein, respectively. Arabidopsis ectopically-expressing MzASMT9 possessed improved melatonin level. Importantly, the MzASMT9 gene was found to be upregulated by high light intensity and salt stress. Increased melatonin due to the highly-expressed MzASMT9 resulted in Arabidopsis lines with enhanced salt tolerance than wild type plants, as indicated by reduced ROS, lowered lipid peroxidation and enhanced photosynthesis. These findings have agricultural applications for the genetic enhancement of melatonin-enriched plants for increasing crop production under a variety of unfavorable environmental conditions.


Assuntos
Arabidopsis/fisiologia , Cloroplastos/metabolismo , Melatonina/biossíntese , Cloreto de Sódio/farmacologia , Estresse Fisiológico/efeitos dos fármacos , Adaptação Fisiológica/efeitos dos fármacos , Adaptação Fisiológica/efeitos da radiação , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Biomassa , Cloroplastos/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Proteínas de Fluorescência Verde/metabolismo , Cinética , Luz , Malondialdeído/metabolismo , Malus/genética , Malus/efeitos da radiação , Fotossíntese/efeitos da radiação , Filogenia , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Proteínas de Plantas/genética , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Espécies Reativas de Oxigênio/metabolismo , Tolerância ao Sal/efeitos dos fármacos , Tolerância ao Sal/efeitos da radiação , Regulação para Cima/genética , Regulação para Cima/efeitos da radiação
13.
Int J Biometeorol ; 61(5): 891-901, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27841003

RESUMO

Climate change impact assessments are predominantly undertaken for the purpose of informing future adaptation decisions. Often, the complexity of the methodology hinders the actionable outcomes. The approach used here illustrates the importance of considering uncertainty in future climate projections, at the same time providing robust and simple to interpret information for decision-makers. By quantifying current and future exposure of Royal Gala apple to damaging temperature extremes across ten important pome fruit-growing locations in Australia, differences in impact to ripening fruit are highlighted, with, by the end of the twenty-first century, some locations maintaining no sunburn browning risk, while others potentially experiencing the risk for the majority of the January ripening period. Installation of over-tree netting can reduce the impact of sunburn browning. The benefits from employing this management option varied across the ten study locations. The two approaches explored to assist decision-makers assess this information (a) using sunburn browning risk analogues and (b) through identifying hypothetical sunburn browning risk thresholds, resulted in varying recommendations for introducing over-tree netting. These recommendations were location and future time period dependent with some sites showing no benefit for sunburn protection from nets even by the end of the twenty-first century and others already deriving benefits from employing this adaptation option. Potential best and worst cases of sunburn browning risk and its potential reduction through introduction of over-tree nets were explored. The range of results presented highlights the importance of addressing uncertainty in climate projections that result from different global climate models and possible future emission pathways.


Assuntos
Mudança Climática , Frutas/efeitos da radiação , Malus/efeitos da radiação , Doenças das Plantas/etiologia , Luz Solar/efeitos adversos , Adaptação Fisiológica , Austrália , Frutas/fisiologia , Malus/fisiologia , Doenças das Plantas/prevenção & controle , Risco , Temperatura
14.
Phys Rev E ; 94(1-1): 012411, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27575168

RESUMO

The effect of the statistical properties of light on the value of the photoinduced reaction of the biological objects, which differ in the morphological and physiological characteristics, the optical properties, and the size of cells, was studied. The fruit of apple trees, the pollen of cherries, the microcuttings of blackberries in vitro, and the spores and the mycelium of fungi were irradiated by quasimonochromatic light fluxes with identical energy parameters but different values of coherence length and radius of correlation. In all cases, the greatest stimulation effect occurred when the cells completely fit in the volume of the coherence of the field, while both temporal and spatial coherence have a significant and mathematically certain impact on the physiological activity of cells. It was concluded that not only the spectral, but also the statistical (coherent) properties of the acting light play an important role in the photoregulation process.


Assuntos
Fungos/efeitos da radiação , Luz , Processos Fotoquímicos , Células Vegetais/efeitos da radiação , Frutas/efeitos da radiação , Malus/efeitos da radiação , Micélio/efeitos da radiação , Pólen/efeitos da radiação , Prunus avium/efeitos da radiação , Rubus/efeitos da radiação
15.
Plant Sci ; 247: 115-26, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27095405

RESUMO

UVR8 (UV Resistance Locus 8) is an ultraviolet-B (UV-B; 280-315nm) light receptor that is involved in regulating many aspects of plant growth and development. UV-B irradiation can increase the development of flower and fruit coloration in many fruit trees, such as grape, pear and apple. Previous investigations of the structure and functions of UVR8 in plants have largely focused on Arabidopsis. Here, we isolated the UVR8 gene from apple (Malus domestica) and analyzed its function in transgenic Arabidopsis. Genomic and protein sequence analysis showed that MdUVR8 shares high similarity with the AtUVR8 protein from Arabidopsis, including the conserved seven-bladed ß-propeller, the C27 region, the 3 "GWRHT" motifs and crucial amino-acid residues (14 Trps, 2 Args). A point mutation prediction and three-dimensional structural analysis of MdUVR8 indicated that it has a similar structure to AtUVR8 and that the crucial residues are also important in MdUVR8. In terms of transcript levels, MdUVR8 expression was up-regulated by UV-B light, which suggests that its expression follows a 24-h circadian rhythm. Using heterologous expression of MdUVR8 in both uvr8-1 mutant and wild-type (WT) Arabidopsis, we found that MdUVR8 regulates hypocotyl elongation and gene expression under UV-B light. These data provide functional evidence for a role of MdUVR8 in controlling photomorphogenesis under UV-B light and indicate that the function of UVR8 is conserved between Arabidopsis and apple. Furthermore, we examined the interaction between MdUVR8 and MdCOP1 (constitutive photomorphogenic1) using a yeast two-hybrid assay and a co-immunoprecipitation assay. This interaction provides a direction for investigating the regulatory mechanisms of the UV-B-light pathway in apple.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Proteínas Cromossômicas não Histona/metabolismo , Malus/genética , Proteínas de Plantas/metabolismo , Transdução de Sinais , Motivos de Aminoácidos , Sequência de Aminoácidos , Arabidopsis/fisiologia , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Proteínas Cromossômicas não Histona/química , Proteínas Cromossômicas não Histona/genética , Clonagem Molecular , Expressão Gênica , Genes Reporter , Hipocótilo/genética , Hipocótilo/fisiologia , Hipocótilo/efeitos da radiação , Malus/fisiologia , Malus/efeitos da radiação , Modelos Moleculares , Mutação , Especificidade de Órgãos , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Plântula/genética , Plântula/fisiologia , Plântula/efeitos da radiação , Alinhamento de Sequência , Análise de Sequência de DNA , Técnicas do Sistema de Duplo-Híbrido , Raios Ultravioleta
16.
Planta ; 244(3): 573-86, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27105885

RESUMO

MAIN CONCLUSION: Paper-bagging treatment can transform non-transcribed MdMYB1 - 2 and MdMYB1 - 3 alleles into transcribed alleles through epigenetic regulations, resulting in the red pigmentation of a normally non-red apple cultivar 'Mutsu.' Anthocyanin biosynthesis in apples is regulated by MdMYB1/A/10, an R2R3-Type MYB gene. 'Mutsu,' a triploid apple cultivar harboring non-transcribed MdMYB1-2 and MdMYB1-3 alleles, retains green skin color under field conditions. However, it can show red/pink pigmentation under natural or artificial ultraviolet-B (UV-B) light exposure after paper-bagging and bag removal treatment. In the present study, we found that in 'Mutsu,' paper bagging-induced red pigmentation was due to the activation of non-transcribed MdMYB1-2/-3 alleles, which triggered the expression of downstream anthocyanin biosynthesis genes in a UV-B-dependent manner. By monitoring the epigenetic changes during UV-B-induced pigmentation, no significant differences in DNA methylation and histone modifications in the 5' upstream region of MdMYB1-2/-3 were recorded between the UV-B-treated fruit skin (red) and the fruit skin treated only by white light (green). In contrast, bag treatment lowered the DNA methylation in this region of MdMYB1-2/-3 alleles. Similarly, higher levels of histone H3 acetylation and trimethylation of H3 tail at lysine 4, and lower level of trimethylation of H3 tail at lysine 27 were observed in the 5' upstream region of MdMYB1-2/-3 in the skin of the fruit immediately after bag removal. These results suggest that bagging treatment can induce epigenetic changes, facilitating the binding of trans factor(s) to MdMYB1-2/-3 alleles, resulting in the activation of these MYBs after bag removal.


Assuntos
Epigênese Genética , Frutas/efeitos da radiação , Malus/metabolismo , Pigmentação/efeitos da radiação , Proteínas de Plantas/metabolismo , Malus/genética , Malus/efeitos da radiação , Proteínas de Plantas/genética , Raios Ultravioleta
17.
Plant Physiol Biochem ; 97: 139-46, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26465670

RESUMO

The objective of this study was to follow changes in the temperature-dependent responses of photosynthesis and photosystem II performance in leaves of field-grown trees of Malus domestica (Borkh.) cv. 'Red Gala' before and after exposure to a long-term heat event occurring late in the growing season. Light-saturated photosynthesis was optimal at 25 °C before the heat event. The high temperatures caused a reduction in rates at low temperatures (15-20 °C) but increased rates at high temperatures (30-40 °C) and a shift in optimum to 30 °C. Rates at all temperatures increased after the heat event and the optimum shifted to 33 °C, indicative of some acclimation to the high temperatures occurring. Photosystem II attributes were all highly temperature-dependent. The operating quantum efficiency of PSII during the heat event declined, but mostly at high temperatures, partly because of decreased photochemical quenching but also from increased non-photochemical quenching. However, a further reduction in PSII operating efficiency occurred after the heat event subsided. Non-photochemical quenching had subsided, whereas photochemical quenching had increased in the post-heat event period and consistent with a greater fraction of open PSII reaction centres. What remained uncertain was why these effects on PSII performance appeared to have no effect on the process of light-saturated photosynthesis. However, the results provide an enhanced understanding of the impacts of sustained high temperatures on the photosynthetic process and its underlying reactions, notably photochemistry.


Assuntos
Malus/fisiologia , Fotossíntese , Complexo de Proteína do Fotossistema II/metabolismo , Aclimatação , Clorofila/metabolismo , Fluorescência , Temperatura Alta , Luz , Malus/efeitos da radiação , Folhas de Planta/fisiologia , Folhas de Planta/efeitos da radiação
18.
PLoS One ; 10(4): e0120124, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25831065

RESUMO

In apple cultivation, simulation models may be used to monitor fruit size during the growth and development process to predict production levels and to optimize fruit quality. Here, Fuji apples cultivated in spindle-type systems were used as the model crop. Apple size was measured during the growing period at an interval of about 20 days after full bloom, with three weather stations being used to collect orchard temperature and solar radiation data at different sites. Furthermore, a 2-year dataset (2011 and 2012) of apple fruit size measurements were integrated according to the weather station deployment sites, in addition to the top two most important environment factors, thermal and sunshine hours, into the model. The apple fruit diameter and length were simulated using physiological development time (PDT), an indicator that combines important environment factors, such as temperature and photoperiod, as the driving variable. Compared to the model of calendar-based development time (CDT), an indicator counting the days that elapse after full bloom, we confirmed that the PDT model improved the estimation accuracy to within 0.2 cm for fruit diameter and 0.1 cm for fruit length in independent years using a similar data collection method in 2013. The PDT model was implemented to realize a web-based management information system for a digital orchard, and the digital system had been applied in Shandong Province, China since 2013. This system may be used to compute the dynamic curve of apple fruit size based on data obtained from a nearby weather station. This system may provide an important decision support for farmers using the website and short message service to optimize crop production and, hence, economic benefit.


Assuntos
Frutas/crescimento & desenvolvimento , Frutas/efeitos da radiação , Malus/crescimento & desenvolvimento , Malus/efeitos da radiação , Sistemas de Informação Administrativa , Luz Solar , Temperatura , Telefone Celular , Internet , Modelos Estatísticos , Fatores de Tempo
19.
Food Microbiol ; 46: 329-335, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25475303

RESUMO

Ultraviolet (UV) light irradiation at 254 nm is considered as a novel non-thermal method for decontamination of foodborne pathogenic bacteria. However, lower penetration depth of UV light at 254 nm in apple juice resulted in higher UV dose consumption during apple juice decontamination. In addition, no studies are available on the reactivation of pathogens following exposure to UV light in drinks and beverages. Two novel monochromatic UV light sources (λ = 222 and 282 nm) have been developed for bacterial disinfection. However, the inactivation of pathogenic Escherichia coli O157:H7 following exposure to these UV wavelengths is still unclear. Therefore, the present study was conducted to determine the inactivation and reactivation potential of pathogenic E. coli O157:H7 in apple juice following exposure to UV light at three monochromatic wavelengths: Far UV (λ = 222 nm), Far UV+ (λ = 282 nm) and UVC light (λ = 254 nm). The results showed that E. coli O157:H7 is acid-resistant, and up to 99.50% of cells survived in apple juice when incubated at 20 °C for 24 h. Inactivation of E. coli O157:H7 following exposure to Far UV light (2.81 Log reduction) was higher (P < 0.05) than the inactivation caused by UVC light (1.95 Log reduction) and Far UV+ light (1.83 Log reduction) at the similar levels of UV fluence of 75 mJ/cm(2). No any reactivation potential was observed for E. coli O157:H7 in dark incubation phases after exposure to UV light as determined by the regular plating method. In addition, the exposure to Far UV light at 222 nm followed by incubating at 37 °C significantly decreased (P < 0.05) the survival of E. coli O157:H7 during dark incubation phase compared to that of UVC and Far UV+ light.


Assuntos
Bebidas/microbiologia , Escherichia coli O157/efeitos da radiação , Irradiação de Alimentos/métodos , Malus/microbiologia , Viabilidade Microbiana/efeitos da radiação , Escherichia coli O157/crescimento & desenvolvimento , Malus/efeitos da radiação , Raios Ultravioleta
20.
Physiol Plant ; 154(1): 54-65, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25185895

RESUMO

The xanthophyll cycle, flavonoid metabolism, the antioxidant system and the production of active oxygen species were analyzed in the peel of 'Fuji' apples re-exposed to sunlight after extended periods of fruit bagging treatment, resulting in different levels of photooxidative sunburn. After re-exposing bagged fruits to sunlight, the production of active oxygen species and the photoprotective capacity in apple peels were both significantly enhanced. As sunburn severity increased, the concentration of hydrogen peroxide increased, while xanthophyll cycle pool size decreased. For the key genes involved in flavonoid synthesis, expressions of MdMYB10 and MdPAL were upregulated, whereas the expressions of MdCHS, MdANS, MdFLS and MdUFGT were downregulated in sunburnt fruit peel. Correspondingly, concentrations of both quercetin-3-glycoside and cyanidin-3-galactoside decreased. Total ascorbate concentrations decreased as sunburn severity increased, with the decrease being faster for oxidized than for reduced ascorbate. Transcription levels of MdGMP, MdGME, MdGGP, MdGPP, MdGalDH and MdGalLDH, the genes involved in ascorbate synthesis, were similar in non-sunburnt and sunburnt fruit peels, whereas activities of l-galactose dehydrogenase and l-galactono-1,4-lactone dehydrogenase decreased in severely sunburnt peel. Although activities of superoxide dismutase and ascorbate peroxidase increased, the activities of monodehydroascorbate reductase, dehydroascorbate reductase and glutathione reductase decreased as sunburn severity increased. In summary, the occurrence of photooxidative sunburn in 'Fuji' apple peel is closely associated with a relatively lower xanthophyll cycle pool size, reduced levels of ascorbate reduction and synthesis and reduced flavonoid synthesis. Our data are consistent with the idea that ascorbate plays a key role in protecting apple fruit from photooxidative sunburn.


Assuntos
Antioxidantes/metabolismo , Flavonoides/metabolismo , Frutas/efeitos da radiação , Malus/efeitos da radiação , Xantofilas/metabolismo , Clorofila/metabolismo , Frutas/metabolismo , Malus/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Luz Solar
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