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1.
J Agric Food Chem ; 67(38): 10563-10576, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31487171

RESUMO

Sulfur (S) metabolism plays a vital role in Cd detoxification, but the collaboration between melatonin biosynthesis and S metabolism under Cd stress remains unaddressed. Using exogenous melatonin, melatonin-deficient tomato plants with a silenced caffeic acid O-methyltransferase (COMT) gene, and COMT-overexpressing plants with cosuppression of sulfate transporter (SUT)1 and SUT2 genes, we found that melatonin deficiency decreased S accumulation and aggravated Cd phytotoxicity, whereas exogenous melatonin or overexpression of COMT increased S uptake and assimilation, resulting in an improved plant growth and Cd tolerance. Melatonin deficiency promoted Cd translocation from root to shoot, but COMT overexpression caused the opposite effect. COMT overexpression failed to compensate the functional hierarchy of S when its uptake was inhibited by cosilencing of transporter SUT1 and SUT2. Our study provides genetic evidence that melatonin-mediated tolerance to Cd is closely associated with the efficient regulation of S metabolism, redox homeostasis, and Cd translocation in tomato plants.


Assuntos
Cádmio/metabolismo , Lycopersicon esculentum/metabolismo , Melatonina/metabolismo , Enxofre/metabolismo , Transporte Biológico , Regulação da Expressão Gênica de Plantas , Lycopersicon esculentum/genética , Lycopersicon esculentum/crescimento & desenvolvimento , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Oxirredução , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteína O-Metiltransferase/genética , Proteína O-Metiltransferase/metabolismo
2.
BMC Plant Biol ; 19(1): 354, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31412779

RESUMO

BACKGROUND: High temperature is a major environmental stress that limits plant growth and agriculture productivity. Mitogen-activated protein kinases (MAPKs) are highly conserved serine and threonine protein kinases that participate in response to diverse environmental stresses in plants. A total of 16 putative SlMAPK genes are identified in tomato, and SlMAPK3 is one of the most extensively studied SlMAPKs. However, the role of SlMAPK3 in response to heat stress is not clearly understood in tomato plants. In this study, we performed functional analysis of SlMAPK3 for its possible role in response to heat stress. RESULTS: qRT-PCR analyses revealed that SlMAPK3 relative expression was depressed by heat stress. Here, wild-type (WT) tomato plants and CRISPR/Cas9-mediated slmapk3 mutant lines (L8 and L13) were used to investigate the function of SlMAPK3 in response to heat stress. Compared with WT plants, slmapk3 mutants exhibited less severe wilting and less membrane damage, showed lower reactive oxygen species (ROS) contents, and presented higher both activities and transcript levels of antioxidant enzymes, as well as elevated expressions of genes encoding heat stress transcription factors (HSFs) and heat shock proteins (HSPs). CONCLUSIONS: CRISPR/Cas9-mediated slmapk3 mutants exhibited more tolerance to heat stress than WT plants, suggesting that SlMAPK3 was a negative regulator of thermotolerance. Moreover, antioxidant enzymes and HSPs/HSFs genes expression were involved in SlMAPK3-mediated heat stress response in tomato plants.


Assuntos
Resposta ao Choque Térmico/genética , Lycopersicon esculentum/genética , Proteínas de Plantas/genética , Espécies Reativas de Oxigênio/metabolismo , Antioxidantes/metabolismo , Técnicas de Inativação de Genes , Homeostase , Lycopersicon esculentum/metabolismo , Proteínas de Plantas/metabolismo
3.
J Chem Ecol ; 45(8): 693-707, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31367970

RESUMO

Crop domestication and selective breeding have altered plant defense mechanisms, influencing insect-plant interactions. A reduction in plant resistance/tolerance against herbivory is generally expected in domesticated species, however, limited efforts have been made to compare inducibility of plant defenses between wild and domesticated genotypes. In the present study, the inducibility of several plant defense mechanisms (e.g. defensive chemicals, trichomes, plant volatiles) were investigated, and the performance and preference of the herbivore Helicoverpa zea were measured in three different tomato genotypes; a) wild tomato, Solanum pimpinellifolium L. (accession LA 2093), b) cherry tomato, S. lycopersicum L. var. cerasiforme (accession Matts Wild Cherry), and c) cultivated tomato, S. lycopersicum L. var. Better Boy). Enhanced inducibility of defensive chemicals, trichomes, and plant volatiles in the cultivated tomato, and a higher level of constitutive plant resistance against herbivory in the wild genotype was observed. When comparing the responses of damaged vs. undamaged leaves, the percent reduction in larval growth was higher on damaged leaves from cultivated tomato, suggesting a higher induced resistance compared to other two genotypes. While all tomato genotypes exhibited increased volatile organic compound (VOCs) emissions in response to herbivory, the cultivated variety responded with generally higher levels of VOCs. Differences in VOC patterns may have influenced the ovipositional preferences, as H. zea female moths significantly preferred laying eggs on the cultivated versus the wild tomato genotypes. Selection of traits during domestication and selective breeding could alter allocation of resources, where plants selected for higher yield performance would allocate resources to defense only when attacked.


Assuntos
Lycopersicon esculentum/química , Mariposas/fisiologia , Solanum/química , Animais , Comportamento Animal/efeitos dos fármacos , Catecol Oxidase/metabolismo , Feminino , Genótipo , Herbivoria , Larva/fisiologia , Lycopersicon esculentum/genética , Lycopersicon esculentum/metabolismo , Oviposição/efeitos dos fármacos , Fenóis/análise , Folhas de Planta/química , Folhas de Planta/metabolismo , Folhas de Planta/parasitologia , Proteínas de Plantas/análise , Análise de Componente Principal , Inibidores de Proteases/química , Solanum/genética , Solanum/metabolismo , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/metabolismo , Compostos Orgânicos Voláteis/farmacologia
4.
Food Chem ; 298: 125040, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31261008

RESUMO

The effects of co-digestion of red cabbage with carrot, baby spinach and/or cherry tomato on the bioaccessibility of anthocyanins and carotenoids such as α-carotene, ß-carotene, lutein and lycopene were examined using a simulated in vitro gastro-intestinal digestion model. The individual vegetables and their mixtures were digested with and without added a standardised salad dressing. Bioaccessibility of total anthocyanins was enhanced by 10-15% (p < 0.05) when red cabbage was co-digested with the carotenoid-rich vegetables, except with carrot. In contrast, the co-digestion of red cabbage with carrot decreased bioaccessibility of total carotenoids by 21-33% (p < 0.05), and with cherry tomato by 42-56% (p < 0.05). The bioaccessibility of a given carotenoid varied depending on the vegetable matrix. Among the tested vegetable mixtures, red cabbage and baby spinach when co-digested demonstrated that anthocyanins and carotenoids were equally bioaccessible (total anthocyanin bioaccessibility of 62-66% and total carotenoid bioaccessibility of 66%).


Assuntos
Antocianinas/farmacocinética , Brassica/química , Carotenoides/farmacocinética , Lycopersicon esculentum/química , Verduras/química , Disponibilidade Biológica , Brassica/metabolismo , Daucus carota/química , Digestão , Humanos , Lycopersicon esculentum/metabolismo , Saliva , Spinacia oleracea/química , Verduras/metabolismo
5.
Food Chem ; 298: 125069, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260991

RESUMO

The effects of ethanol treatment on quality characteristics of cherry tomatoes were investigated over 11 days of storage at room temperature (25 °C). Results showed that sensory quality was improved after ethanol treatment, with redder, softer fruits at the edible stage (11 days) compared with control fruit. In addition, the contents of ascorbic acid, sucrose and fructose were elevated after ethanol treatment as well as the concentration of 6-methyl-5-hepten-2-one. Conversely, decreased levels of methyl salicylate (MeSA), guaiacol, (Z)-3-hexenal and (E)-2-hexenal were observed. Selected consumers showed a preference for ethanol-treated cherry tomato fruits compared with controls. Taken together, 0.1% ethanol application has the potential to improve the quality characteristics of cherry tomatoes stored at room temperature.


Assuntos
Etanol/farmacologia , Lycopersicon esculentum/efeitos dos fármacos , Aldeídos/química , Ácido Ascórbico/análise , Cromatografia Líquida de Alta Pressão , Análise Discriminante , Aromatizantes/análise , Frutas/química , Frutas/efeitos dos fármacos , Frutas/metabolismo , Humanos , Análise dos Mínimos Quadrados , Lycopersicon esculentum/química , Lycopersicon esculentum/metabolismo , Salicilatos/química , Açúcares/análise , Temperatura Ambiente , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/isolamento & purificação
6.
Food Chem ; 298: 125062, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31280088

RESUMO

The industrial transformation of tomato (Lycopersicon esculentum Mill.) produces processed foods, such as dried tomatoes. In this study two varieties (SaAb and PerBruzzo), grown in three cropping systems (one conventional and two organic ones), were processed by two types of small-scale drying (oven or sun drying), over two years of production. The dried samples were analyzed for their non-volatile and volatile composition, relating the results with sensory analysis. The multivariate analysis performed on collected data allowed a detailed comparison of the effects of processing, year-to year variation and cropping systems. Results indicated that drying methods mainly influenced the composition and flavor profile, also affected by the production year. The cropping system significantly influenced some quality indices, such as the acid and sugar amounts, and the aldehydes, respectively higher and lower in organic samples. The comprehensive PCA analysis allowed discrimination of drying methods and, to a lesser extent, cropping systems.


Assuntos
Aromatizantes/química , Lycopersicon esculentum/química , Nariz Eletrônico , Aromatizantes/análise , Liofilização , Frutas/química , Frutas/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Lycopersicon esculentum/metabolismo , Agricultura Orgânica , Análise de Componente Principal , Estações do Ano , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química
7.
BMC Plant Biol ; 19(1): 331, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31357955

RESUMO

BACKGROUND: Salt stress is one of the environmental factors that greatly limits crop production worldwide because high salt concentrations in the soil affect morphological responses and physiological and metabolic processes, including root morphology and photosynthetic characteristics. Soil aeration has been reported to accelerate the growth of plants and increase crop yield. The objective of this study was to examine the effects of 3 NaCl salinity levels (28, 74 and 120 mM) and 3 aeration volume levels (2.3, 4.6 and 7.0 L/pot) versus non-aeration and salinity treatments on the root morphology, photosynthetic characteristics and chlorophyll content of potted tomato plants. RESULTS: The results showed that both aeration volume and salinity level affected the root parameters, photosynthetic characteristics and chlorophyll content of potted tomato plants. The total length, surface area and volume of roots increased with the increase in aeration volume under each NaCl stress level. The effect was more marked in the fine roots (especially in ≤1 mm diameter roots). Under each NaCl stress level, the photosynthetic rate and chlorophyll content of tomato significantly increased in response to the aeration treatments. The net photosynthetic rate and chlorophyll a and t content increased by 39.6, 26.9, and 17.9%, respectively, at 7.0 L/pot aeration volume compared with no aeration in the 28 mM NaCl treatment. We also found that aeration could reduce the death rate of potted tomato plants under high salinity stress conditions (120 mM NaCl). CONCLUSIONS: The results suggest that the negative effect of NaCl stress can be offset by soil aeration. Soil aeration can promote root growth and increase the photosynthetic rate and chlorophyll content, thus promoting plant growth and reducing the plant death rate under NaCl stress conditions.


Assuntos
Lycopersicon esculentum/fisiologia , Fotossíntese , Raízes de Plantas/anatomia & histologia , Clorofila/metabolismo , Lycopersicon esculentum/anatomia & histologia , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/metabolismo , Raízes de Plantas/fisiologia , Salinidade , Estresse Salino , Solo
8.
BMC Plant Biol ; 19(1): 323, 2019 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-31319801

RESUMO

BACKGROUND: Exogenous 5-aminolevulinic acid (ALA) positively regulates plants chlorophyll synthesis and protects them against environmental stresses, although the protection mechanism is not fully clear. Here, we explored the effects of ALA on chlorophyll synthesis in tomato plants, which are sensitive to low temperature. We also examined the roles of the glutathione S-transferase (GSTU43) gene, which is involved in ALA-induced tolerance to oxidation stress and regulation of chlorophyll synthesis under low temperature. RESULTS: Exogenous ALA alleviated low temperature caused chlorophyll synthesis obstacle of uroporphyrinogen III (UROIII) conversion to protoporphyrin IX (Proto IX), and enhanced the production of chlorophyll and its precursors, including endogenous ALA, Proto IX, Mg-protoporphyrin IX (Mg-proto IX), and protochlorophyll (Pchl), under low temperature in tomato leaves. However, ALA did not regulate chlorophyll synthesis at the level of transcription. Notably, ALA up-regulated the GSTU43 gene and protein expression and increased GST activity. Silencing of GSTU43 with virus-induced gene silencing reduced the activities of GST, superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase, and increased the membrane lipid peroxidation; while fed with ALA significant increased all these antioxidase activities and antioxidant contents, and alleviated the membrane damage. CONCLUSIONS: ALA triggered GST activity encoded by GSTU43, and increased tomato tolerance to low temperature-induced oxidative stress, perhaps with the assistance of ascorbate- and/or a glutathione-regenerating cycles, and actively regulated the plant redox homeostasis. This latter effect reduced the degree of membrane lipid peroxidation, which was essential for the coordinated synthesis of chlorophyll.


Assuntos
Ácido Aminolevulínico/metabolismo , Clorofila/metabolismo , Genes de Plantas/fisiologia , Glutationa Transferase/metabolismo , Lycopersicon esculentum/genética , Proteínas de Plantas/metabolismo , Ácido Aminolevulínico/farmacologia , Resposta ao Choque Frio , Glutationa Transferase/genética , Homeostase/efeitos dos fármacos , Peroxidação de Lipídeos , Lycopersicon esculentum/efeitos dos fármacos , Lycopersicon esculentum/metabolismo , Lycopersicon esculentum/fisiologia , Oxirredução/efeitos dos fármacos , Proteínas de Plantas/genética
9.
Carbohydr Polym ; 219: 181-190, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31151515

RESUMO

Water-soluble fraction (WSF), CDTA-soluble fraction (CSF), sodium carbonate-soluble fraction (SSF), loosely-bonding KOH-soluble fractions (LKF) and tightly-bonding KOH-soluble fractions (TKF) were sequentially extracted from tomato cell wall polysaccharides. Physicochemical properties and functional bioactivities of these different bonding state tomato fruit polysaccharides (DBTP) were investigated. WSF, CSF and SSF were identified as pectic polysaccharides, while LKF and TKF were identified as hemicellulose. WSF, possessing plenty of galacturonic acids, was considered as an aggregative of linear homogalacturonan with extremely high molecular weight. CSF and SSF, rich in neutral sugars side chains, contained abundant rhamnogalacturonan regions. These polysaccharides exhibited distinct surface morphology and special FTIR spectrums. Thermal analysis manifested that LKF and TKF exhibited higher thermal stability. WSF and SSF showed higher apparent viscosity and elasticity. Assays for functional bioactivities suggested that CSF and SSF displayed stronger antioxidant activities, while CSF, SSF and TKF exhibited higher hypolipidemic activities.


Assuntos
Parede Celular/química , Frutas , Lycopersicon esculentum , Polissacarídeos , Antioxidantes/farmacologia , Elasticidade , Frutas/citologia , Frutas/metabolismo , Hipolipemiantes/farmacologia , Lycopersicon esculentum/citologia , Lycopersicon esculentum/metabolismo , Pectinas/química , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Polissacarídeos/farmacologia , Solubilidade , Viscosidade
10.
J Sci Food Agric ; 99(13): 5842-5851, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31206706

RESUMO

BACKGROUND: The current need to produce food for a growing population, from diminishing natural resources, such as water and energy, and with minimum environmental degradation, demands the optimization of production. We compare the economic feasibility of tomato production in an open system with a perlite substrate, a closed system with the nutrient film technique (NFT), and a hydroponic crop (deep flow technique, DFT) using three levels of salinity that are found within the normal range for irrigation water quality in southeastern Spain. RESULTS: Production with DFT resulted in an increase in the cost of phytosanitary treatments and the cost of maintenance. Production with perlite resulted in an increase in the cost of irrigation water and fertilization, and the use of NFT resulted in an increase in energy costs. The point of price equilibrium was exceeded in the three soilless systems when using low salinity water, and in perlite, with intermediate salinity water. CONCLUSION: Profitability was reduced in the following order: perlite > NFT > DFT. There were positive results when using irrigation water with low salinity, and in the case of perlite, with intermediate salinity. In every case, salinity reduced the profitability of the operation, and this was greater when NFT was employed. The analysis of these soilless systems should be continued to determine the possibility of reducing cultivation costs. © 2019 Society of Chemical Industry.


Assuntos
Irrigação Agrícola/economia , Produção Agrícola/economia , Produção Agrícola/métodos , Lycopersicon esculentum/economia , Lycopersicon esculentum/crescimento & desenvolvimento , Águas Salinas/economia , Irrigação Agrícola/métodos , Análise Custo-Benefício , Lycopersicon esculentum/metabolismo , Águas Salinas/análise , Águas Salinas/metabolismo , Salinidade , Cloreto de Sódio/análise
11.
Food Chem ; 296: 9-16, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31202311

RESUMO

Z-lycopene isomers are more bioavailable than all-E-lycopene, especially 5-Z-lycopene. Based on our observations, the addition of unblanched onion could favor Z-isomerization of lycopene (by more than 94%) during heating tomato-onion-extra virgin olive oil (EVOO) purees at 90 °C for 2 h. The increase in Z-lycopene was correlated linearly with the addition of unblanched onion, with R2 > 0.92, and increased rates of 5-Z-lycopene were 3-4 times higher than for 9-Z-lycopene and 13-Z-lycopene. Diallyl disulfide (DADS), formed by alliinase-catalyzed breakdown of non-volatile precursors in onion, contributed to these increases and correlated linearly (R2 > 0.79, 0-0.50 mg/g puree) with increased Z-lycopene. Increased rates of 5-Z-lycopene were also 3-4 times higher than for 9-Z-lycopene and 13-Z-lycopene. However, blanching of onion, in tomato-onion-EVOO purees, before heating, significantly decreased the effect of onion on Z-isomerization of lycopene.


Assuntos
Lipídeos/química , Licopeno/química , Lycopersicon esculentum/química , Cebolas/química , Compostos Alílicos/química , Cromatografia Líquida de Alta Pressão , Dissulfetos/química , Isomerismo , Licopeno/análise , Lycopersicon esculentum/metabolismo , Azeite de Oliva/química , Cebolas/metabolismo , Temperatura Ambiente
12.
Food Chem ; 295: 300-310, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174762

RESUMO

While fleshy fruit softening has long been mechanistically linked to cell wall disassembly, the importance of the fruit cuticle in water relations and firmness has been suggested through studies of the long-shelf life delayed fruit deterioration (dfd) tomato genotype. We tested the hypothesis that dynamic cuticle properties and composition affect tomato fruit transpiration and firmness and are influenced by environmental water availability, using dfd and two normally softening fruit cultivars, Ailsa Craig (AC) and M82, grown under control and water stress (WS) conditions. The effect of WS was also assessed following fruit detachment. WS increased fruit firmness, cuticle load, and the expression of cuticle biosynthetic genes, while reducing cuticle permeability and fruit transpiration rate in AC and M82, but not in dfd fruit. This study supports a direct relationship between fruit cuticle properties, transpiration and firmness, and provides insights into the adaptation of tomato genotypes to environments where water can be scarce.


Assuntos
Desidratação , Frutas/fisiologia , Lycopersicon esculentum/fisiologia , Armazenamento de Alimentos , Frutas/química , Frutas/metabolismo , Genótipo , Lycopersicon esculentum/química , Lycopersicon esculentum/metabolismo , Transpiração Vegetal , Água/metabolismo
13.
Food Chem ; 293: 220-225, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151604

RESUMO

This study was conducted for quantitative determination of quercetin in food and fruit juice samples based on a green, fast, and accurate method namely, micro-cloud point extraction (MCPE). The proposed MCPE is essentially a miniaturized form of traditional cloud point extraction (CPE) in which only a few microliters of micellar extracting phase is sufficient for determination. Factors influencing the extraction efficiency, such as amount of Triton X-114 (5%, v/v), effect of pH, amount of Na2SO4 salt (5%, w/v) and time of centrifugation were investigated and optimized by experimental design. Under the optimized condition, the calibration range was found to be linear over 10-100 ng mL-1 with the limit of detection of 2.2 ng mL-1. The relative standard deviation of 2.8%, was obtained on a 30 ng mL-1quercetin standard solution (n = 3). Finally, the proposed method was successfully applied for the determination of quercetin in onion, tomato, apple and orange juice samples.


Assuntos
Análise de Alimentos/métodos , Sucos de Frutas e Vegetais/análise , Quercetina/análise , Calibragem , Centrifugação , Fracionamento Químico , Concentração de Íons de Hidrogênio , Limite de Detecção , Lycopersicon esculentum/química , Lycopersicon esculentum/metabolismo , Cebolas/química , Cebolas/metabolismo , Polietilenoglicóis/química , Quercetina/isolamento & purificação , Espectrofotometria/normas
14.
Ecotoxicol Environ Saf ; 181: 248-254, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31200197

RESUMO

Although the North Delta region in Egypt is one of the most densely populated areas in the world, it suffers from a severe shortage of fresh water needed to irrigate crops. So usually farmers resort to the use of low-quality water, such as agricultural drainage water, which could pose a threat to the quality of crops and then human health. Two field experiments were carried out during two consecutive summer seasons of 2014 and 2015 aimed at delivering more information about the pros and cons of alternative irrigation for tomato using fresh and agricultural drainage water with or without applying of magnetic field. The twelve surface irrigations, which tomato needs during its whole growing season, were applied alternatively between fresh and agricultural drainage water, respectively, at the following percentages (100 + 0), (75 + 25), (50 + 50), (25 + 75) and (0 + 100). Magnetic field was applied using iron fillings at a rate of 150 kg ha-1. The results revealed that growth parameters, early, total and relative yield, marketable yield and total chlorophyll and NPK content of leaves were gradually decreased with increasing the irrigation using agricultural drainage water. However, irrigating tomato by 100% fresh water had the highest values, while using of 100% agricultural drainage water displayed the lowest values. Contrarily, vitamin C, total soluble solids (TSS) and fruit firmness where at their highest values when tomato irrigated by 100% of agricultural drainage water. Applying of magnetic field not only enhances the growth, yield and quality of tomato under irrigation using agricultural water but also under fresh water. These results are of importance in areas where the use of agricultural drainage water irrigating crops is inevitable for enhancing yield and its quality and consequently ensuring food safety.


Assuntos
Irrigação Agrícola , Lycopersicon esculentum/crescimento & desenvolvimento , Campos Magnéticos , Agricultura , Ácido Ascórbico/metabolismo , Egito , Água Doce , Frutas , Humanos , Lycopersicon esculentum/metabolismo , Folhas de Planta/metabolismo , Estações do Ano , Água
15.
J Chem Ecol ; 45(7): 598-609, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31218595

RESUMO

Insect herbivory induces plant defense responses that are often modulated by components in insect saliva, oral secretions or regurgitant, frass, or oviposition fluids. These secretions contain proteins and small molecules that act as elicitors or effectors of plant defenses. Several non-protein elicitors have been identified from insect oral secretions, whereas studies of insect saliva have focused mainly on protein identification. Yet, insect saliva may also contain non-protein molecules that could activate defense responses in plants. The goal of this study was to identify non-protein plant defense elicitors present in insect saliva. We used the fall armyworm (FAW), Spodoptera frugiperda and its host plants tomato, maize, and rice as a model system. We tested the effect of protein-digested saliva or non-protein components on herbivore-induced defense responses in maize, rice and tomato. We identified phytohormones in FAW saliva using high performance liquid chromatography coupled with mass spectrometry. The results of this study show that non-protein components in FAW saliva modulated defense responses in different plant species. The saliva of this insect contains benzoic acid, and the phytohormones jasmonic acid, salicylic acid, and abscisic acid at concentrations of <5 ng per µl of saliva. Plant treatment with similar phytohormone quantities detected in FAW saliva upregulated the expression of a maize proteinase inhibitor gene in maize, and down-regulated late herbivore-induced defenses in tomato plants. We conclude that FAW saliva is a complex fluid that, in addition to known enzymatic plant defense elicitors, contains phytohormones and other small molecules.


Assuntos
Reguladores de Crescimento de Planta/análise , Saliva/química , Zea mays/metabolismo , Animais , Cromatografia Líquida de Alta Pressão , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Herbivoria , Larva/metabolismo , Lycopersicon esculentum/metabolismo , Lycopersicon esculentum/parasitologia , Espectrometria de Massas , Reguladores de Crescimento de Planta/farmacologia , Folhas de Planta/metabolismo , Folhas de Planta/parasitologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Saliva/metabolismo , Spodoptera/crescimento & desenvolvimento , Zea mays/parasitologia
16.
J Microbiol Biotechnol ; 29(7): 1124-1136, 2019 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-31216607

RESUMO

Salinity is one of the major abiotic stresses that cause reduction of plant growth and crop productivity. It has been reported that plant growth-promoting bacteria (PGPB) could confer abiotic stress tolerance to plants. In a previous study, we screened bacterial strains capable of enhancing plant health under abiotic stresses and identified these strains based on 16s rRNA sequencing analysis. In this study, we investigated the effects of two selected strains, Bacillus aryabhattai H19-1 and B. mesonae H20-5, on responses of tomato plants against salinity stress. As a result, they alleviated decrease in plant growth and chlorophyll content; only strain H19-1 increased carotenoid content compared to that in untreated plants under salinity stress. Strains H19-1 and H20-5 significantly decreased electrolyte leakage, whereas they increased Ca2+ content compared to that in the untreated control. Our results also indicated that H20-5-treated plants accumulated significantly higher levels of proline, abscisic acid (ABA), and antioxidant enzyme activities compared to untreated and H19-1-treated plants during salinity stress. Moreover, strain H20-5 upregulated 9-cisepoxycarotenoid dioxygenase 1 (NCED1) and abscisic acid-response element-binding proteins 1 (AREB1) genes, otherwise strain H19-1 downregulated AREB1 in tomato plants after the salinity challenge. These findings demonstrated that strains H19-1 and H20-5 induced ABA-independent and -dependent salinity tolerance, respectively, in tomato plants, therefore these strains can be used as effective bio-fertilizers for sustainable agriculture.


Assuntos
Bacillus/fisiologia , Lycopersicon esculentum/fisiologia , Reguladores de Crescimento de Planta/farmacologia , Tolerância ao Sal/efeitos dos fármacos , Ácido Abscísico/metabolismo , Antioxidantes/metabolismo , Clorofila/metabolismo , Fertilizantes , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Proteínas de Plantas/genética , Prolina/metabolismo , Estresse Salino
17.
J Agric Food Chem ; 67(25): 6930-6939, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31150236

RESUMO

In many regions, reuse of reclaimed water (RW) is a necessity for irrigation. The presence of organic microcontaminants (OMCs) in RW and their translocation to plants may represent a risk of human exposure. Nevertheless, information available about real field crops is scarce and focused on a limited number of compounds. The novelty of this work relies on the application of a wider-scope analytical approach based on a multianalyte target analysis (60 compounds) and a suspect screening (>1300 compounds). This methodology was applied to real field-grown tomato crops irrigated with RW. The study revealed the presence of 17 OMCs in leaves (0.04-32 ng g-1) and 8 in fruits (0.01-1.1 ng g-1), 5 of them not reported before in real field samples. A health-risk assessment, based on the toxicological threshold concern (TTC) concept, showed that RW irrigation applied under the conditions given does not pose any threat to humans.


Assuntos
Frutas/química , Lycopersicon esculentum/metabolismo , Águas Residuárias/análise , Poluentes Químicos da Água/análise , Irrigação Agrícola , Transporte Biológico , Frutas/metabolismo , Humanos , Lycopersicon esculentum/química , Folhas de Planta/química , Folhas de Planta/metabolismo , Medição de Risco , Água/química , Poluentes Químicos da Água/metabolismo
18.
J Plant Physiol ; 239: 28-37, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31177028

RESUMO

Predominant NH4+ nutrition causes an "ammonium syndrome" that induces metabolic changes and thereby provides resistance against Pseudomonas syringae infection through the activation of systemic acquired acclimation (SAA). Hence, to elucidate the mechanisms underlying NH4+-mediated SAA, the changes in nutrient balance and C and N skeletons were studied in NH4+-treated plants upon infection by P. syringae. A general decrease in cation and an increase in anion levels was observed in roots and leaves of NH4+-treated plants. Upon NH4+-based nutrition and infection, tomato leaves showed an accumulation of S, P, Zn, and of Mn. Mn accumulation might be required for ROS detoxification since it acts as a cofactor of superoxide dismutase (SOD). Primary metabolism was modified in both tissues of NH4+-fed plants to counteract NH4+ toxicity by decreasing TCA intermediates. A significant increase in Arg, Gln, Asn, Lys, Tyr, His and Leu was observed in leaves of NH4+-treated plants. The high level of the putrescine precursor Arg hints towards the importance of the Glu pathway as a key metabolic check-point in NH4+-treated and infected plants. Taken together, NH4+-fed plants displayed a high level of basal responses allowing them to activate SAA and to trigger defense responses against P. syringae through nutrient imbalances and changes in primary metabolism.


Assuntos
Compostos de Amônio/metabolismo , Carbono/metabolismo , Lycopersicon esculentum/metabolismo , Nitrogênio/metabolismo , Doenças das Plantas/microbiologia , Pseudomonas syringae/fisiologia , Compostos de Amônio/administração & dosagem , Resistência à Doença , Fertilizantes , Lycopersicon esculentum/microbiologia , Nutrientes/administração & dosagem , Nutrientes/metabolismo
19.
J Plant Physiol ; 239: 83-91, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31229903

RESUMO

In higher plants ammonium (NH4+) assimilation occurs mainly through the glutamine synthetase/glutamate synthase (GS/GOGAT) pathway. Nevertheless, when plants are exposed to stress conditions, such as excess of ammonium, the contribution of alternative routes of ammonium assimilation such as glutamate dehydrogenase (GDH) and asparagine synthetase (AS) activities might serve as detoxification mechanisms. In this work, the in vivo functions of these pathways were studied after supplying an excess of ammonium to tomato (Solanum lycopersicum L. cv. Agora Hybrid F1) roots previously adapted to grow under either nitrate or ammonium nutrition. The short-term incorporation of labelled ammonium (15NH4+) into the main amino acids was determined by GC-MS in the presence or absence of methionine sulphoximine (MSX) and azaserine (AZA), inhibitors of GS and GOGAT activities, respectively. Tomato roots were able to respond rapidly to excess ammonium by enhancing ammonium assimilation regardless of the previous nutritional regime to which the plant was adapted to grow. The assimilation of 15NH4+ could take place through pathways other than GS/GOGAT, since the inhibition of GS and GOGAT did not completely impede the incorporation of the labelled nitrogen into major amino acids. The in vivo formation of Asn by AS was shown to be exclusively Gln-dependent since the root was unable to incorporate 15NH4+ directly into Asn. On the other hand, an in vivo aminating capacity was revealed for GDH, since newly labelled Glu synthesis occurred even when GS and/or GOGAT activities were inhibited. The aminating GDH activity in tomato roots responded to an excess ammonium supply independently of the previous nutritional regime to which the plant had been subjected.


Assuntos
Compostos de Amônio/metabolismo , Glutamato Desidrogenase/metabolismo , Lycopersicon esculentum/metabolismo , Raízes de Plantas/metabolismo , Aminação , Compostos de Amônio/administração & dosagem , Fertilizantes , Lycopersicon esculentum/efeitos dos fármacos , Lycopersicon esculentum/enzimologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia
20.
Plant Mol Biol ; 100(6): 647-658, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31154655

RESUMO

KEY MESSAGE: Found a trans-splicing of PHYTOENE SYNTHASE 1 alters tomato fruit color by map-based cloning, functional complementation and RACE providing an insight into fruit color development. Color is an important fruit quality trait and a major determinant of the economic value of tomato (Solanum lycopersicum). Fruit color inheritance in a yellow-fruited cherry tomato (cv. No. 22), named yellow-fruited tomato 2 (yft2), was shown to be controlled by a single recessive gene, YFT2. The YFT2 gene was mapped in a 95.7 kb region on chromosome 3, and the candidate gene, PHYTOENE SYNTHASE 1 (PSY1), was confirmed by functional complementation analysis. Constitutive over expression of PSY1 in yft2 increased the accumulation of carotenoids and resulted in a red fruit color, while no causal mutation was detected in the YFT2 allele of yft2, compared with red-fruited SL1995 cherry tomato or cultivated variety (cv. M82). Expression of YFT2 3' region in yft2 was significantly lower than in SL1995, and further studies revealed a difference in YFT2 post-transcriptional processing in yft2 compared with SL1995 and cv. M82, resulting in a longer YFT2 transcript. The alternatively trans-spliced allele of YFT2 in yft2 is predicted to encode a novel LT-YFT2 protein of 432 amino acid (AA) residues, compared to the 412 AA YFT2 protein of SL1995. The trans-spliced event also resulted in significantly down regulated expression of YFT2 in yft2 tomato, and the YFT2 allele suppressed expression of the downstream genes involved in the carotenoid biosynthesis pathway and carotenoids synthesis by a mechanism of the feed-forward regulation. In conclusion, we found that trans-splicing of YFT2 alters tomato fruit color, providing new insights into fruit color development.


Assuntos
Lycopersicon esculentum/metabolismo , Pigmentação/genética , Proteínas de Plantas/metabolismo , Processamento Alternativo , Carotenoides/metabolismo , Mapeamento Cromossômico , Clonagem Molecular , Cor , DNA Complementar/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Genes Recessivos , Teste de Complementação Genética , Genótipo , Lycopersicon esculentum/genética , Mutação , Proteínas de Plantas/genética , Trans-Splicing
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