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1.
J Sci Food Agric ; 100(3): 1350-1357, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31617215

RESUMO

BACKGROUND: Non-conventional water sources and water-saving techniques can be valuable in semi-arid regions, although their long-term effects on citrus quality are little known. This study evaluated the effects of irrigation with two sources, transfer water (TW) and reclaimed water (RW), combined with two irrigation strategies, full irrigation (FI) and regulated deficit irrigation (RDI), on fruit quality of mandarins and grapefruits during eight growth seasons. RESULTS: Reclaimed water irrigation in mandarin, without water restriction, influenced maturity index (MI) less than TW-FI, because titratable acidity (TA) increased to a greater degree than soluble solid contents (SSC). Nevertheless, juice quality standards were satisfied. Regardless of the irrigation treatment (FI or RDI), a trend towards increasing fruit weight was also detected with RW. In grapefruit, its rootstock (Citrus macrophylla) enhanced salinity resilience with respect to the rootstock of mandarin ('Carrizo' citrange) and, hence, MI was not affected by RW. The RDI strategy, without saline stress (TW-RDI), increased, to a similar degree, both SSC and TA in mandarin fruit, not affecting the MI. In grapefruit, the water stress of RDI did improve the MI due to the TA did not change and SSC increased significantly, the TA did not change. The combination of both strategies, RW-RDI, decreased the MI only in some years because TA increased proportionally more than SSC in mandarin. CONCLUSIONS: The medium- and long-term feasibility of using RW and RDI to irrigate citrus was demonstrated. However, they must be performed cautiously and with appropriate management to avoid damaging fruit quality as a result of phytotoxic elements. © 2019 Society of Chemical Industry.


Assuntos
Irrigação Agrícola/métodos , Citrus/crescimento & desenvolvimento , Frutas/química , Água/metabolismo , Citrus/química , Citrus/metabolismo , Frutas/crescimento & desenvolvimento , Frutas/metabolismo , Águas Salinas/análise , Águas Salinas/metabolismo , Água/análise
2.
J Sci Food Agric ; 100(1): 193-200, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31502246

RESUMO

BACKGROUND: Lemon processing procedures yield a significant amount of waste as peels, which are 57% of processed lemons and represent a possible source of bioactive compounds (essential oils, EOs). EOs were extracted from lemon fruits belonging to four cultivars harvested at four different sampling times (25 October, 23 November, 20 December, 1 February), characterized, and quantified through gas chromatography-mass spectrometry. RESULTS: The chemical composition of EOs highlighted that 26 compounds of the four lemon cultivars at the different ripening stages were clearly identified. The compounds analysed belonged to four chemical classes: monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpenes, and fatty alcohol esters. Among the monoterpene hydrocarbons, d-limonene, ß-pinene, and γ-terpinene were the most abundant; and among the oxygenated monoterpenes, α-terpineol, nerol, and geraniol were the most abundant. Quantitative gas chromatography-mass spectrometry analysis of the most abundant monoterpene hydrocarbons (α-pinene, ß-pinene, myrcene, d-limonene, and γ-terpinene) highlighted that the amount of EOs decreased during ripening stages. 'Ovale di Sorrento' and 'Sfusato Amalfitano' showed the highest level of EOs in December, whereas in 'Femminello Cerza' and 'Femminello Adamo' this occurred in November. EOs, as well as the phenolic compounds, were positively correlated with the antioxidant activity (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid). CONCLUSIONS: EOs reached the highest level in the four lemon cultivars at different ripening stages. Campanian cultivars ('Ovale di Sorrento' and 'Sfusato Amalfitano') showed the greatest EO content in November, whereas in Sicilian cultivars ('Femminello Cerza' and 'Femminello Adamo') this occurred in December. Besides phenolic compounds, measured in lemon peel extracts, EOs can contribute to antioxidant activity, as demonstrated by the positive correlation. © 2019 Society of Chemical Industry.


Assuntos
Citrus/crescimento & desenvolvimento , Frutas/química , Óleos Voláteis/química , Óleos Vegetais/química , /análise , Citrus/química , Frutas/crescimento & desenvolvimento , Sesquiterpenos/análise
3.
Biomed Res Int ; 2019: 9058715, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31534966

RESUMO

Although the physiological and molecular responses of Citrus to Al-toxicity or low pH have been examined in some details, little information is available on Citrus responses to pH and aluminum (Al) interactions. Citrus sinensis seedlings were irrigated for 18 weeks with nutrient solution at a concentration of 0 or 1 mM AlCl3•6H2O and a pH of 2.5, 3.0, 3.5, or 4.0. Thereafter, biomass, root, stem, and leaf concentrations of Al and nutrients, leaf gas exchange, chlorophyll a fluorescence (OJIP) transients, and related parameters were investigated to understand the physiological mechanisms underlying the elevated pH-induced alleviation of Citrus toxicity. Increasing the nutrient solution pH from 2.5 to 4.0 alleviated the Al-toxic effects on biomass, photosynthesis, OJIP transients and related parameters, and element concentrations, uptake, and distributions. In addition, low pH effects on the above physiological parameters were intensified by Al-toxicity. Evidently, a synergism existed between low pH and Al-toxicity. Increasing pH decreased Al uptake per root dry weight and its concentration in roots, stems, and leaves and increased nitrogen, phosphorus, calcium, magnesium, sulfur, and boron uptake per plant and their concentrations in roots, stems, and leaves. This might be responsible for the elevated pH-induced alleviation of growth inhibition and the impairment of the whole photosynthetic electron transport chain, thus preventing the decrease of CO2 assimilation.


Assuntos
Cloreto de Alumínio/farmacologia , Citrus/crescimento & desenvolvimento , Complexo de Proteínas da Cadeia de Transporte de Elétrons/metabolismo , Fotossíntese/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Alumínio/farmacologia , Concentração de Íons de Hidrogênio
4.
Chemosphere ; 236: 124385, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31545192

RESUMO

Heavy metal pollution may affect plant growth. The focus of this study was to explore remediation agents that alleviate cadmium toxicity in plants. The Citrus maxima (grapefruit) seedlings were cultivated for 10 days under hydroponic conditions amended with different concentrations of Cd2+ (50 and 200 mg/L) and CDs (600 and 900 mg/L). Our observations on roots and leaves showed that, the plant exposed to 200 mg/L Cd2+ alone was damaged, supported by the changes in anthocyanin contents, activity of antioxidant enzymes and cell membrane peroxidation damage (up to 35.8-45%). However, the physiological properties of the plant were improved upon exposed to 200 mg/L Cd2+ plus 900 mg/L CDs; it can be ascribed to Cd2+ sorption to the co-exposed CDs which reduced its freely dissolved concentration by more than 22.5%, thus significantly reducing the amount of Cd2+ entered the plant roots by 50.7-89.4%. Due to the oxidative stress induced by Cd2+ exposure at 200 mg/L, expression of glutathione-producing genes was up-regulated by 30-360% relative to the control, while the genes expression upon exposure to 200 mg/L Cd2+ and 900 mg/L CDs was reduced by 48.4-91.5% relative to that exposed to 200 mg/L Cd2+ alone. However, detoxification of CDs on plant leaves at 600 mg/L was insignificant, because a portion of Cd2+ taken up by roots can be transported to leaves associated with the internalized CDs. Therefore, CDs can be utilized as a repair agent to mitigate toxicity of Cd2+ to plant especially at a high amendment level (900 mg/L).


Assuntos
Cádmio/toxicidade , Citrus/efeitos dos fármacos , Pontos Quânticos/química , Adsorção , Antioxidantes/metabolismo , Cádmio/química , Cádmio/metabolismo , Carbono/química , Carbono/metabolismo , Citrus/crescimento & desenvolvimento , Citrus/metabolismo , Produção Agrícola , Glutationa/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Pontos Quânticos/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo
5.
J Agric Food Chem ; 67(36): 10010-10017, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31414816

RESUMO

Dominican farmers have started to apply synthetic auxin herbicides (SAHs) as the main alternative to mitigate the impacts of the occurrence of glyphosate-resistant (GR) Parthenium hysterophorus populations in citrus orchards. A GR P. hysterophorus population survived field labeled rates of glyphosate, 2,4-dichlorophenoxyacetic acid (2,4-D), dicamba, and picloram, which showed poor control (<50%). In in vivo assays, resistance levels were high for glyphosate and moderate for picloram, dicamba, and 2,4-D. Sequencing the 5-enolpyruvylshikimate-3-phosphate synthase gene revealed the double Thr-102-Ile and Pro-106-Ser amino acid substitution, conferring resistance to glyphosate. Additionally, reduced absorption and impaired translocation contributed to this resistance. Regarding SAH, impaired 2,4-D transport and enhanced metabolism were confirmed in resistant plants. The application of malathion improved the efficacy of SAHs (control >50%), showing that metabolism of these herbicides was mediated by cytochrome P450 enzymes. This study reports, for the first time, multiple resistance to SAHs and glyphosate in P. hysterophorus.


Assuntos
Asteraceae/efeitos dos fármacos , Citrus/crescimento & desenvolvimento , Glicina/análogos & derivados , Resistência a Herbicidas , Herbicidas/farmacologia , Ácidos Indolacéticos/farmacologia , Ácido 2,4-Diclorofenoxiacético/metabolismo , Ácido 2,4-Diclorofenoxiacético/farmacologia , Asteraceae/metabolismo , Dicamba/metabolismo , Dicamba/farmacologia , Glicina/metabolismo , Glicina/farmacologia , Herbicidas/metabolismo , Ácidos Indolacéticos/metabolismo
6.
Environ Sci Pollut Res Int ; 26(29): 30188-30205, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31422532

RESUMO

Seedlings of 'Shatian pummelo' (Citrus grandis) and 'Xuegan' (Citrus sinensis) were supplied daily with nutrient solution at a concentration of 0.5 (control), 100, 200, 300, 400, or 500 µM CuCl2 for 6 months. Thereafter, seedling growth; leaf, root, and stem levels of nutrients; leaf gas exchange; levels of pigments; chlorophyll a fluorescence (OJIP) transients and related parameters; leaf and root relative water content; levels of nonstructural carbohydrates; H2O2 production rate; and electrolyte leakage were comprehensively examined (a) to test the hypothesis that Cu directly damages root growth and function, thus impairing water and nutrient uptake and hence inhibiting shoot growth; (b) to establish whether the Cu-induced preferential accumulation of Cu in the roots is involved in Cu tolerance of Citrus; and (c) to elucidate the possible causes for the Cu-induced decrease in photosynthesis. Most of the growth and physiological parameters were greatly altered only at 300-500 µM (excess) Cu-treated seedlings. Cu supply increased the level of Cu in the roots, stems, and leaves, with a greater increase in the roots than that in the stems and leaves. Many of the fibrous roots became rotten and died under excess Cu. These findings support the hypothesis that Cu directly damages root growth and function, thus impairing water and nutrient uptake and hence inhibiting shoot growth, and the conclusion that the preferential accumulation of Cu in the roots under excess Cu is involved in the tolerance of Citrus to Cu toxicity. The lower CO2 assimilation in excess Cu-treated leaves was caused mainly by nonstomatal factors, including structural damage to thylakoids, feedback inhibition due to increased accumulation of nonstructural carbohydrates, decreased uptake of water and nutrients, increased production of reactive oxygen species, and impaired photosynthetic electron transport chain. Also, we discussed the possible causes for the excess Cu-induced decrease in leaf pigments and accumulation of nonstructural carbohydrates in the roots and leaves.


Assuntos
Clorofila A/metabolismo , Citrus/efeitos dos fármacos , Cobre/farmacologia , Fotossíntese/efeitos dos fármacos , Complexo de Proteína do Fotossistema II/metabolismo , Água/metabolismo , Transporte Biológico , Metabolismo dos Carboidratos/efeitos dos fármacos , Citrus/crescimento & desenvolvimento , Citrus/metabolismo , Citrus sinensis/efeitos dos fármacos , Citrus sinensis/crescimento & desenvolvimento , Citrus sinensis/metabolismo , Fluorescência , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Plântula/metabolismo
7.
Molecules ; 24(14)2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31311090

RESUMO

Finger citron (Citrus medica var. sarcodactylis) is a popular ornamental tree and an important source of essential oils rich in terpenoids, but the mechanisms behind volatile formation are poorly understood. We investigated gene expression changes combined with volatile profiling of ten samples from three developing organs: flower, leaf, and fruit. A total of 62 volatiles were identified with limonene and γ-terpinene being the most abundant ones. Six volatiles were identified using partial least squares discriminant analysis (PLS-DA) that could be used as markers for distinguishing finger citron from other citrus species. RNA-Seq revealed 1,611,966,118 high quality clean reads that were assembled into 32,579 unigenes. From these a total of 58 terpene synthase (TPS) gene family members were identified and the spatial and temporal distribution of their transcripts was measured in developing organs. Transcript levels of transcription factor genes AP2/ERF (251), bHLH (169), bZIP (76), MYB (155), NAC (184), and WRKY (66) during finger citron development were also analyzed. From extracted subnetworks of three modules constructed by weighted gene co-expression network analysis (WGCNA), thirteen TPS genes and fifteen transcription factors were suggested to be related to volatile terpenoid formation. These results provide a framework for future investigations into the identification and regulatory network of terpenoids in finger citron.


Assuntos
Citrus/química , Perfilação da Expressão Gênica/métodos , Metabolômica/métodos , Terpenos/análise , Citrus/genética , Citrus/crescimento & desenvolvimento , Flores/química , Flores/genética , Frutas/química , Frutas/genética , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Análise dos Mínimos Quadrados , Óleos Voláteis/química , Folhas de Planta/química , Folhas de Planta/genética , Proteínas de Plantas/genética , Análise de Sequência de RNA
8.
GM Crops Food ; 10(3): 139-158, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31311388

RESUMO

To be commercialized and grown in the US, genetically engineered (GE) crops typically go through an extensive food, feed, and environmental safety assessment process which, in certain instances, requires complex consultations with three different US regulatory agencies. Many small market, niche, and specialty crops have been genetically engineered using the modern tools of recombinant DNA but few have been commercialized due to real or perceived regulatory constraints. This workshop discussed the practical aspects of developing dossiers on GE specialty, niche, or small-market crops/products for submission to US regulatory agencies. This workshop focused on actual case studies, and provided an opportunity for public or private sector scientists and crop developers to spend time with regulatory officials to learn the specifics of compiling a dossier for regulatory approval. The objective of the workshop was to explain and demystify data requirements and regulatory dossier compilation by small companies, academics, and other developers.


Assuntos
Produtos Agrícolas/crescimento & desenvolvimento , Indústria Alimentícia/legislação & jurisprudência , Engenharia Genética/legislação & jurisprudência , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Citrus/genética , Citrus/crescimento & desenvolvimento , Congressos como Assunto , Resistência à Doença , Gossypium/genética , Gossypium/crescimento & desenvolvimento , Gossypium/metabolismo , Gossipol/metabolismo , Solanum tuberosum/genética , Solanum tuberosum/crescimento & desenvolvimento , Estados Unidos , United States Department of Agriculture , United States Environmental Protection Agency
9.
Plant Sci ; 285: 224-229, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203887

RESUMO

Why evergreen fruit tree species accumulate starch in the ovary during flower bud differentiation in spring, as deciduous species do during flower bud dormancy, is not fully understood. This is because in evergreen species carbon supply is assured by leaves during flower development. We suggest the existence of an autonomous mechanism in the flowers which counteracts the competition for photoassimilates with new leaves, until they become source organs. Our hypothesis is that starch accumulated during Citrus ovary ontogeny originates from 1) its own photosynthetic capacity and 2) the mobilization of reserves. Through defoliation experiments, we found that ovaries accumulate starch during flower ontogeny using a dual mechanism: 1) the autotrophic route of source organs activating Rubisco (RbcS) genes expression, and 2) the heterotrophic route of sink organs that hydrolyze sucrose in the cytosol. Defoliation 40 days before anthesis did not significantly reduce ovary growth, flower abscission or starch concentration up to 20 days after anthesis (i.e. 60 days later). Control flowers activated the energy depletion signaling system (i.e. SnRK1) and RbcS gene expression around athesis. Defoliation accelerated and boosted both activities, increasing SPS gene expression (sucrose synthesis), and SUS1, SUS3 and cwINV (sucrose hydrolysis) to maintain a glucose threshold which satisfied its need to avoid abscission.


Assuntos
Metabolismo dos Carboidratos/fisiologia , Citrus/crescimento & desenvolvimento , Flores/fisiologia , Frutas/crescimento & desenvolvimento , Citrus/metabolismo , Citrus/fisiologia , Flores/crescimento & desenvolvimento , Flores/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Transcriptoma
10.
Biosci Biotechnol Biochem ; 83(10): 1924-1936, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31244380

RESUMO

This study examined the physiological effects of different amounts of nitrogen (N) supplementation (0 to 2.72 kg/year) on the citrus cultivar Huangguogan (Citrus reticulata × Citrus sinensis). Root activity, chlorophyll content, and fruit quality were measured, and the activities of the antioxidant enzymes superoxide dismutase (SOD), guaiacol peroxidase (POD), and catalase (CAT), and the contents of malondialdehyde (MDA) and soluble protein in root, leaf, and fruit tissues were examined at different developmental stages. Root activity, chlorophyll content, fruit quality, antioxidant enzyme activity, MDA content, and soluble protein content increased in plants treated with an appropriate amount of N. Both excessive N and N deficiency decreased the content of MDA and the activities of antioxidant enzymes. Application of 1.36-1.81 kg N/year is suggested for citrus fertilization and the lower end of this range is recommended for minimizing environmental impact and production cost.


Assuntos
Antioxidantes/metabolismo , Catalase/metabolismo , Citrus/enzimologia , Citrus/crescimento & desenvolvimento , Nitrogênio/administração & dosagem , Peroxidase/metabolismo , Superóxido Dismutase/metabolismo , Clorofila/metabolismo , Citrus/metabolismo , Malondialdeído/metabolismo , Proteínas de Plantas/metabolismo , Estruturas Vegetais/enzimologia , Estruturas Vegetais/metabolismo
11.
Curr Microbiol ; 76(9): 1066-1072, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31243536

RESUMO

Seven endophytic yeast strains were isolated from tangerine peel (Citrus reticulata Blanco) and genotyped through clustering with D1/D2 and ITS1-5.8S-ITS2 sequences from GenBank. Phenotypic characteristics were obtained through commercial kits and through assisted species identification. Indole-3-acetic acid (IAA) production by the yeast strains was assessed using Salkowski reagent and High-Performance Liquid chromatography (HPLC). The growth-promoting effects of the yeast were evaluated using the 'ragdoll' method. CRYb1, CRYb2 and CRYb7 isolates were identified as the closest species Hanseniaspora opuntiae. CRYb3 was identified as Pichia kluyveri. CRYb4, CRYb5 and CRYb6 were identified as Meyerozyma guilliermondii. CRYb1, CRYb5, CRYb6 and CRYb7 were found to be capable of IAA production. The most promising yeast strains now require further evaluation for their ability to promote plant growth in vitro and in vivo. These data increase our knowledge of the distribution and biological properties of endophytic yeast. This is important information that will be required to fully harness the growth-promoting properties of yeast strains.


Assuntos
Citrus/microbiologia , Endófitos/isolamento & purificação , Frutas/microbiologia , Pichia/isolamento & purificação , Citrus/efeitos dos fármacos , Citrus/crescimento & desenvolvimento , Endófitos/classificação , Endófitos/genética , Endófitos/metabolismo , Ácidos Indolacéticos/metabolismo , Ácidos Indolacéticos/farmacologia , Filogenia , Pichia/classificação , Pichia/genética , Pichia/metabolismo
12.
J Vis Exp ; (145)2019 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-30907871

RESUMO

Phytotron has been widely used to assess the effect of numerous parameters on the development of many species. However, less information is available on how to achieve fast profuse flowering in young fruit trees with this plant growth chamber. This study aimed to outline the design and performance of a fast clear methodology to force flowering in young mandarin trees (cv. Nova and cv. Clemenules) and to analyze the influence of induction intensity on inflorescence type. The combination of a short water stress period with simulated spring conditions (day 13 h, 22 °C, night 11 h, 12 °C) in the phytotron allowed flowers to be obtained only after 68-72 days from the time the experiment began. Low-temperature requirements were adequately replaced with water stress. Floral response was proportional to water stress (measured as the number of fallen leaves): the greater the induction, the larger the quantity of flowers. Floral induction intensity also influenced inflorescence type and dates for flowering. Details on artificial lighting (lumens), photoperiod, temperatures, plant size and age, induction strategy and days for each stage are provided. Obtaining flowers from fruit trees at any time, and also several times a year, can have many advantages for researchers. With the methodology proposed herein, three, or even four, flowering periods can be forced each year, and researchers should be able to decide when, and they will know, the duration of the entire process. The methodology can be useful for: flower production and in vitro pollen germination assays; experiments with pests that affect early fruit development stages; studies on fruit physiological alterations. All this can help plant breeders to shorten times to obtain male and female gametes to perform forced-crosses.


Assuntos
Citrus/fisiologia , Flores/fisiologia , Fotoperíodo , Árvores/fisiologia , Citrus/genética , Citrus/crescimento & desenvolvimento , Temperatura Baixa , Flores/genética , Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Inflorescência/fisiologia , Árvores/genética , Árvores/crescimento & desenvolvimento
13.
PLoS One ; 14(3): e0213874, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30897177

RESUMO

Nitrogen metabolism in citrus has received increased attention due to its effects on plant growth and productivity. However, little is known about the effects of nitrogen fertilization on nitrogen metabolism in young trees of citrus cultivar 'Huangguogan' (Citrus reticulata × Citrus sinensis). Here, genes encoding nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate dehydrogenase (GDH), and asparagine synthetase (AS), represented as HgNR, HgNiR, HgGS, HgGDH, and HgAS, respectively, were cloned from Huangguogan. Deduced protein sequences were analyzed and proteins were confirmed to be localized in their respective cellular organelles. Moreover, pot-cultured 'Huangguogan' seedlings were fertilized with 0 (N1), 1.36 (N2), 1.81 (N3), 2.26 (N4), or 2.72 (N5) kg N/year, for 12 months. Enzyme activity and enzyme-gene expression were studied in roots, leaves, and fruits at different stages. Finally, the effects of N application rate on root activity, leaf N, soluble protein, yield, and fruit quality at the ripening stage were measured. The results showed that: 1) HgNR, HgNiR, HgGDH, and HgAS gene products were found mainly in the cytoplasm and plasma membrane, while HgGS gene product was found mainly in cytoplasm and mitochondria. 2) Gene expression and enzyme activity differed among plant organs. As the root is in permanent direct contact with the soil we suggest that root gene expression and enzyme activity can be used as reference to determine N application rate. 3) Yield, fruit quality, enzyme activity, and enzyme-related gene expression were considerably lower at low than at high-N supply. However, they were all inhibited by excess nitrogen (i.e., 2.72 kg/year). Therefore, we recommend 1.81 kg N/year as the optimal N application rate for young 'Huangguogan' trees.


Assuntos
Citrus/metabolismo , Nitrogênio/metabolismo , Proteínas de Plantas/metabolismo , Citrus/crescimento & desenvolvimento , Citoplasma/metabolismo , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Glutamato Desidrogenase/classificação , Glutamato Desidrogenase/genética , Glutamato Desidrogenase/metabolismo , Glutamato-Amônia Ligase/classificação , Glutamato-Amônia Ligase/genética , Glutamato-Amônia Ligase/metabolismo , Nitrato Redutase/classificação , Nitrato Redutase/genética , Nitrato Redutase/metabolismo , Filogenia , Folhas de Planta/metabolismo , Proteínas de Plantas/classificação , Proteínas de Plantas/genética , Raízes de Plantas/metabolismo , Plântula/crescimento & desenvolvimento , Plântula/metabolismo
14.
Anal Chim Acta ; 1056: 62-69, 2019 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-30797461

RESUMO

The traditional Chinese medicine Citri Reticulatae Pericarpium (CRP) was mainly originated from the dried pericarp of Citrus reticulata 'Chachi' (Crc), Citrus reticulata 'Dahongpao' (Crd), Citrus reticulata 'Unshiu' (Cru) and Citrus reticulata 'Tangerina' (Crt) in China. Since these four cultivars have great similarities in morphology, reliable methods to differentiate CRP cultivars have rarely been reported. To discriminate the differences of these CRP cultivars, herein an efficient and reliable method by combining metabolomics, DNA barcoding and electronic nose was first established. The hierarchical three-step filtering metabolomics analysis based on liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) indicated that 9 species-specific chemical markers including 6 flavanone glycosides and 3 polymethoxyflavones could be considered as marker metabolites for discrimination of the geoherb Crc from other cultivars. A total of 19 single nucleotide polymorphism (SNP) sites were found in nuclear internal transcribed spacer 2 (ITS2) of CRP, and three stable SNP sites (33, 128 and 174) in the ITS2 region can distinguish the four CRP cultivars. The electronic nose coupled with chemometrics could also be used to effectively distinguish Crc from other CRP cultivars. Therefore, our results indicated that the integrated method will be an effective strategy for discrimination of similar herbal medicines.


Assuntos
Citrus/classificação , Código de Barras de DNA Taxonômico , Nariz Eletrônico , Metabolômica , Citrus/genética , Citrus/crescimento & desenvolvimento , Citrus/metabolismo , DNA Intergênico/genética
15.
BMC Plant Biol ; 19(1): 47, 2019 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-30704398

RESUMO

BACKGROUND: Harvest time is a relevant economic trait in citrus, and selection of cultivars with different fruit maturity periods has a remarkable impact in the market share. Generation of early- and late-maturing cultivars is an important target for citrus breeders, therefore, generation of knowledge regarding the genetic mechanisms controlling the ripening process and causing the early and late phenotypes is crucial. In this work we analyze the evolution of the transcriptome during fruit ripening in 3 sport mutations derived from the Fina clementine (Citrus clementina) mandarin: Clemenules (CLE), Arrufatina (ARR) and Hernandina (HER) that differ in their harvesting periods. CLE is considered a mid-season cultivar while ARR and HER are early- and late-ripening mutants, respectively. RESULTS: We used RNA-Seq technology to carry out a time course analysis of the transcriptome of the 3 mutations along the ripening period. The results indicated that in these mutants, earliness and lateness during fruit ripening correlated with the advancement or delay in the expression of a set of genes that may be implicated in the maturation process. A detailed analysis of the transcription factors known to be involved in the regulation of fruit ripening identified a member of the MADS box family whose expression was lower in ARR, the early-ripening mutant, and higher in HER, the late-ripening mutant. The pattern of expression of this gene during the maturation period was basically contrary to those of the ethylene biosynthetic genes, SAM and ACC synthases and ACC oxidase. The gene was present in hemizygous dose in the early-ripening mutant. CONCLUSIONS: Our analysis provides new clues about the genetic control of fruit ripening in citrus and allowed the identification of a transcription factor that could be involved in the early phenotype.


Assuntos
Citrus/crescimento & desenvolvimento , Frutas/crescimento & desenvolvimento , Proteínas de Domínio MADS/fisiologia , Proteínas de Plantas/fisiologia , Citrus/genética , Citrus/metabolismo , Frutas/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Genes de Plantas/fisiologia , Proteínas de Domínio MADS/genética , Proteínas de Plantas/genética , Característica Quantitativa Herdável
16.
J Sci Food Agric ; 99(8): 4142-4149, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30767237

RESUMO

BACKGROUND: 'Nules Clementine' mandarin was used to investigate the potential involvement of endogenous plant hormones in mediating citrus fruit susceptibility to rind breakdown disorder (RBD). The effect of light exposure (namely canopy position and bagging treatments) on the endogenous concentration of ABA, 7'-hydroxy-abscisic acid (7-OH-ABA), ABA-glucose ester (ABA-GE) and dihydrophaseic acid (DPA), and t-zeatin was tested using four preharvest treatments: outside, outside bagged, inside and inside bagged. Phytohormones concentration was evaluated during nine weeks of postharvest storage at 8 °C. RESULTS: The shaded fruit inside the canopy had the highest RBD score (0.88) at the end of postharvest storage, while sun-exposed fruit had the lowest score (0.12). Before storage, ABA concentration was lowest (462.8 µg kg-1 ) for inside fruit, and highest in outside bagged fruit (680.5 µg kg-1 ). Although ABA concentration suddenly increased from the third week, reaching a maximum concentration of 580 µg kg-1 at week 6 in fruit from inside position, it generally reduced 1.6-fold ranging from 240.52 to 480.65 µg kg-1 throughout storage. The increase of 7-OH-ABA was more prominent in fruit from inside canopy. Overall, the concentration of ABA-GE increased three-fold with storage time. DPA concentration of bagged fruit from inside canopy position was significantly higher compared to outside fruit. The lower ABA-GE and higher DPA concentration in inside bagged fruit throughout storage also coincided with higher RBD. CONCLUSION: The strong positive correlations between 7-OH-ABA, DPA and RBD incidence demonstrated that these ABA catabolites could be used as biomarkers for fruit susceptibility to the disorder. © 2019 Society of Chemical Industry.


Assuntos
Ácido Abscísico/metabolismo , Citrus/metabolismo , Citocininas/metabolismo , Frutas/crescimento & desenvolvimento , Reguladores de Crescimento de Planta/metabolismo , Ácido Abscísico/química , Citrus/crescimento & desenvolvimento , Citrus/efeitos da radiação , Citocininas/química , Frutas/metabolismo , Frutas/efeitos da radiação , Luz , Reguladores de Crescimento de Planta/química
17.
Pest Manag Sci ; 75(2): 405-412, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29952069

RESUMO

BACKGROUND: Several phytoseiid species can potentially control the citrus rust mite (CRM). Their effectiveness varies, however, as do their intraguild interactions. Under laboratory conditions, Euseius stipulatus, E. scutalis and Iphiseius degenerans preyed effectively on CRM, whereas Amblyseius swirskii and Typhlodromus athiasae had no effect on CRM. In combination with A. swirskii, Euseius numbers were reduced due to intraguild predation, and consequently CRM suppression was less effective. In the field, predatory mite species can be variably provisioned by windborne pollen released from cover crops such as Rhodes grass (RG). We aimed to determine the effects of RG on the phytoseiid community in two field experiments, on different cultivars (pomelo and Shamouti orange). We also tested these communities for negative interspecific abundance relationships that are expected if their respective laboratory-observed intraguild interactions are manifested in the field. RESULTS: Overall, on pomelo, we observed a dominance of A. swirskii, relatively low E. stipulatus and high CRM abundances. Amblyseius swirskii and E. stipulatus abundances were both elevated near RG, despite apparent intraguild predation by A. swirskii. Conversely, T. athiasae abundances were lower near RG, likely due to predation by A. swirskii. On Shamouti, E. stipulatus abundances were much higher than on pomelo and were not negatively related to A. swirskii abundances. There, RG increased E. stipulatus abundance, and CRM was reduced. CONCLUSION: RG cover cropping can enhance CRM control, depending on variation in intraguild interactions among phytoseiids, particularly between A. swirskii and E. stipulatus. These may be modulated by climatic and/or cultivar effects. © 2018 Society of Chemical Industry.


Assuntos
Ácaros/fisiologia , Controle Biológico de Vetores/métodos , Poaceae/crescimento & desenvolvimento , Comportamento Predatório , Acaricidas/toxicidade , Animais , Citrus/crescimento & desenvolvimento , Israel , Poaceae/fisiologia , Pólen
18.
J Sci Food Agric ; 99(3): 1020-1028, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30009387

RESUMO

BACKGROUND: Citrus fruits possess a high content of bioactive compounds whose changes during fruit maturation have not been studied in depth. Fruits were sampled from week 1, after fruit onset (7 days after flowering), to week 14. Volatile compounds isolated by headspace-solid-phase microextraction and polar extracts from all samples were analyzed by gas chromatography-mass spectrometry. RESULTS: The relative abundance of 107 identified metabolites allowed differences among samples at different stages of fruit growth to be established. Principal component analysis showed a clear discrimination among samples, and analysis of variance revealed significant differences in 94 out of the 107 metabolites. Among total volatiles, monoterpenes increased their relative abundance from 86% to 94% during fruit growth, d-limonene, γ-terpinene and ß-pinene being the most abundant; conversely, sesquiterpenes decreased from 11.5% to 2.8%, ß-bisabolene and α-bergamotene being the most concentrated. Sugars, in general, exhibited a gradual increase in abundance, reaching a maximum between weeks 9 and 12. Citric and malic acids, representing approximately 90% of the total identified carboxylic acids, reached a maximum concentration at commercial maturity (week 14). CONCLUSION: Of the 107 tentatively identified metabolites during Persian lime growth, sugars, carboxylic acids, and volatiles were those that experienced more significant changes and more clearly created differences among fruit growth stages. © 2018 Society of Chemical Industry.


Assuntos
Citrus/metabolismo , Frutas/química , Ácidos Carboxílicos/metabolismo , Citrus/crescimento & desenvolvimento , Frutas/crescimento & desenvolvimento , Cromatografia Gasosa-Espectrometria de Massas/métodos , Açúcares/metabolismo , Compostos Orgânicos Voláteis/metabolismo
19.
Physiol Plant ; 165(2): 183-197, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30091288

RESUMO

Plants growing in the field are subjected to multiple stress factors acting simultaneously. Abnormally high temperatures are expected to affect wild plants and crops in the next years due to global warming. In this work, we have studied physiological, hormonal and molecular responses of the citrus rootstock, Carrizo citrange (Poncirus trifoliata L. Raf. × Citrus sinensis L. Osb.) subjected to wounding or high salinity occurring individually or in combination with heat stress. According to our results, combination of high salinity and heat stress aggravated the negative effects of salt intoxication in Carrizo. The high transpiration rate caused by high temperatures counteracted physiological responses of plants to salt stress and increased Cl- intake in leaves. In addition, 12-oxo-phytodienoic acid accumulated specifically under combination of wounding and heat stress, whereas at low temperatures, wounded plants accumulated jasmonic acid (JA) and JA-isoleucine (JA-Ile). Moreover, an antagonism between salicylic acid (SA) and JA was observed, and wounded plants subjected to high temperatures did not accumulate JA nor JA-Ile whereas SA levels increased (via isochorismate synthase biosynthetic pathway). Wounded plants did not accumulate abscisic acid (ABA) but its catabolite phaseic acid. This could act as a signal for the upregulation of (ABA)-RESPONSIVE ELEMENT (ABRE)-BINDING TRANSCRIPTION FACTOR 2 (CsAREB2) and RESPONSIVE TO DISSECATION 22 (CsRD22) in an ABA-independent way. This work uncovers some mechanisms that explain Carrizo citrange tolerance to high temperatures together with different hormonal signals in response to specific stresses. It is suggested that co-occurring abiotic stress conditions can modify (either enhance or reduce) the hormonal response to modulate specific responses.


Assuntos
Citrus/fisiologia , Temperatura Alta , Reguladores de Crescimento de Planta/farmacologia , Estresse Fisiológico , Ácido Abscísico/metabolismo , Cloretos/metabolismo , Citrus/efeitos dos fármacos , Citrus/genética , Citrus/crescimento & desenvolvimento , Ciclopentanos/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Modelos Biológicos , Oxilipinas/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/fisiologia , Estômatos de Plantas/efeitos dos fármacos , Estômatos de Plantas/fisiologia , Transpiração Vegetal/efeitos dos fármacos , Transpiração Vegetal/fisiologia , Água
20.
Braz J Biol ; 79(3): 395-403, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30231137

RESUMO

The objective of this trial was to characterize the assemblage structure of fruit flies (Diptera: Tephritidae) by determining the diversity and faunal indices. Fruit flies were collected for ten years between 2003 and 2015 in six municipalities of the Metropolitan Region of Curitiba, Paraná. The orchards were divided into three crop protection strategies: organic, conventional, and integrated pest management. The characteristic of each community was determined using the Shannon-Wiener, Margalef, and Pielou's indexes. The frequency, constancy, and dominance indexes were also determined. Biological material was analyzed using the explanatory variables: site, crop, plant protection strategy, and susceptibility period. A total of 8,089 fruit flies were collected, of which 4,681 were females. The species Anastrepha daciformis Bezzi, A. dissimilis Stone, A. distincta Greene and A. pickeli Lima were recorded for the first time in Paraná State, the occurrence of three other species was recorded for the first time in the Metropolitan Region of Curitiba (A. montei Lima, A. obliqua Macquart, and A. sororcula Zucchi), in addition A. fraterculus (Wiedemann), A. grandis (Macquart) and Ceratitis capitata (Wiedemann). A. fraterculus accounted for 98.5% of the collected species. Only A. fraterculus and A. sororcula were found in fruits. Fruit flies occurred predominantly in peach trees cultivated under organic conditions. The Shannon index indicated that the municipality of Cerro Azul had the highest diversity and richness whereas apple orchards had the lowest diversity. Crops cultivated under organic conditions exhibited the highest diversity whereas those cultivated under conventional conditions had the highest evenness index. The largest specimens number was collected during the period of crop susceptibility.


Assuntos
Distribuição Animal , Biodiversidade , Produção Agrícola/métodos , Produtos Agrícolas , Tephritidae/fisiologia , Animais , Brasil , Citrus/crescimento & desenvolvimento , Produtos Agrícolas/crescimento & desenvolvimento , Feminino , Florestas , Masculino , Agricultura Orgânica , Rosaceae/crescimento & desenvolvimento , Tephritidae/classificação
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