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1.
Environ Pollut ; 252(Pt B): 941-949, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31252132

RESUMO

The accumulation of bound and conjugated polyamines (PAs) is an important protective trait in plants under adverse environmental conditions. However, their role in plant responses to aluminum (Al) stress remains largely unknown. In this study, we showed that Al treatment increased bound putrescine (Put) levels in the wheat root tips of Al-tolerant Xi Aimai-1, with little effect on its bound spermidine and conjugated PAs or that of Al-sensitive Yangmai-5. Terminating bound Put increments with a synthesis inhibitor (Phenanthroline, o-phen) exacerbated Al-induced root inhibition and callose production. However, it had no significant effect on Al uptake or distribution under Al stress. Instead, Al-induced reactive oxygen species (ROS) production and thus, oxidative damage, was greatly exacerbated by o-phen in the roots of Xi Aimai-1. Application of o-phen barely affected the two ROS generating enzymes (plasma membrane NADPH oxidase and cell wall-bound polyamine oxidase) in wheat roots. However, exogenous o-phen significantly reduced antioxidant enzyme (superoxide dismutase, ascorbate peroxidase, and catalase) activity, which positively correlated with the level of bound Put in Xi Aimai-1. These results clearly suggest that bound Put accumulation works to protect against Al-induced oxidative damage, possibly by maintaining antioxidant capacity in wheat.


Assuntos
Alumínio/toxicidade , Antioxidantes/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Putrescina/metabolismo , Poluentes do Solo/toxicidade , Triticum , Tolerância a Medicamentos , Oxirredução , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Triticum/efeitos dos fármacos , Triticum/enzimologia
2.
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
3.
Plant Physiol Biochem ; 141: 225-230, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31185367

RESUMO

The present study evaluated the role of nitric oxide (NO) in mediating adventitious root (AR) growth, lignification and related enzymatic changes in the hypocotyls of Vigna radiata. To meet the objectives, the changes in AR growth, lignin content, and the activities of enzymes-peroxidases, polyphenol oxidases, and phenylalanine ammonia lyases- with NO donor and its scavenger were monitored. Hypocotyls were cultivated in aqueous solution supplemented with different concentrations of SNP (sodium nitroprusside, NO donor compound) and its scavenging compound (2,4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; cPTIO). Specifically, at low concentrations, SNP induced AR growth, increased the total lignin content and altered the activities of related oxidoreductases- peroxidases, polyphenol oxidases and phenylalanine ammonia lyases- which are involved in lignin biosynthesis pathway. At higher concentrations, a decline in AR growth and lignification was noticed. We analysed the function of NO in AR formation by depleting the endogenous NO using scavenging compound cPTIO. Hypocotyls grown in a medium supplemented with scavenger cPTIO exhibited significant decline in AR growth and the activities of lignin synthesizing enzymes. Application of NO scavenger showed that stimulatory properties on root lignification may be owing to NO itself. In addition, changes in AR growth were significantly correlated with these modified biochemical activities. Our analysis revealed that NO supplementation induces prominent alterations in lignin level during AR formation and this might be due to an alteration in the activity of lignin biosynthetic enzymes, which further affected the polymerization of monolignols and AR growth.


Assuntos
Hipocótilo/enzimologia , Lignina/química , Óxido Nítrico/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Vigna/enzimologia , Catecol Oxidase/metabolismo , Oxirredutases/metabolismo , Peroxidase/metabolismo , Fenilalanina Amônia-Liase/metabolismo , Raízes de Plantas/enzimologia
4.
Environ Pollut ; 250: 831-838, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31051394

RESUMO

Nano- and microplastics have been widely spread in environmental matrices, especially in marine and terrestrial systems. In this study, higher plant Vicia faba root tips were exposed to 5 µm and 100 nm with 10, 50 and 100 mg/L polystyrene fluorescent microplastics (PS-MPs) for 48 h. Root length, weight, oxidative stress and genotoxicity of V. faba were assessed to investigate toxic effects of PS-MPs. The results showed that the biomass and catalase (CAT) enzymes activity of V. faba roots decreased under 5 µm PS-MPs whereas superoxide dismutase (SOD) and peroxidase (POD) enzymes activity significantly increased. Under the 100 nm PS-MPs exposure a significant decrease of growth was observed only at the highest concentration (100 mg/L). However, micronucleus (MN) test and antioxidative enzymes activities showed that 100 nm PS-MPs induce higher genotoxic and oxidative damage to V. faba than 5 µm PS-MPs. Furthermore, the laser confocal scanning microscopy (LCSM) demonstrated that 100 nm PS-MPs can accumulate in V. faba root and most probably block cell connections or cell wall pores for transport of nutrients. These findings provide a new insight into the toxic effects of microplastics on V. faba, and further apply to the ecological risk assessment of microplastics on higher plants.


Assuntos
Antioxidantes/metabolismo , Dano ao DNA , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Estresse Oxidativo/efeitos dos fármacos , Poliestirenos/toxicidade , Vicia faba/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ecotoxicologia , Testes para Micronúcleos , Modelos Teóricos , Tamanho da Partícula , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Vicia faba/enzimologia , Vicia faba/genética
5.
Ecotoxicol Environ Saf ; 180: 179-184, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31082582

RESUMO

Selenium (Se) and zinc (Zn) are necessary mineral nutrients for human body but millions of people have an inadequate intake of them, and eat food enriched with Se and Zn may minimize these problems. Chinese cabbage is an important food in people's daily life. The aim of this study was to evaluate the effects of single Se, Zn and their combination treatment in soil on their accumulation, antioxidant system and lipid peroxidation in roots and leaves of Chinese cabbage using soil pot culture experiment. When 0.5 mg kg-1 Se +30 mg kg-1 Zn and 1.0 mg kg-1 Se +30 mg kg-1 Zn were spiked in soils, Zn concentrations in roots and leaves of Chinese cabbage were significantly increased (p < 0.05) by 20.2%, 37.8% and 17.9%, 34.1% respectively compared to the treatment of 30 mg kg-1 Zn added, and the latter was significantly higher (p < 0.05) than that of former, indicating Se significantly promoted Zn accumulation. Almost all physiological indexes including POD, SOD, CAT, APX, GR, Chlorophyll a, Chlorophyll b, Carotenoids, MDA and Free proline in the treatments of Se or Zn spiked were significantly improved (p < 0.05) or basically unaffected compared to the control without Se or Zn added. The biomass change trends were similar with these indexes either. These results showed that the addition in soil of Se and Zn significantly increased their accumulation in Chinese cabbage without affected its formal growth. Particularly, the addition of Se promoted Zn accumulation. The conclusions were more important reference for the production practice of cash crop enriched of Se and Zn either.


Assuntos
Brassica/efeitos dos fármacos , Selênio/farmacologia , Solo , Zinco/metabolismo , Antioxidantes/metabolismo , Brassica/enzimologia , Brassica/metabolismo , Carotenoides/metabolismo , Clorofila/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Raízes de Plantas/metabolismo , Selênio/metabolismo
6.
Plant Sci ; 283: 366-374, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128707

RESUMO

The tau (U) and phi (F) classes of glutathione transferase (GST) enzymes reduce the glutathione (GSH) pool using GSH as a co-substrate, thus influence numerous redox-dependent processes including hormonal and stress responses. We performed detailed analysis of the redox potential and reactive oxygen species levels in longitudinal zones of 7-day-old roots of Arabidopsis thaliana L. Col-0 wild type and Atsgtf8 and Atgstu19 insertional mutants. Using redox-sensitive cytosolic green fluorescent protein (roGFP2) the redox status of the meristematic, transition, and elongation zones was determined under control and salt stress (3-hour of 75 or 150 mM NaCl treatment) conditions. The Atgstu19 mutant had the most oxidized redox status in all root zones throughout the experiments. Using fluorescent dyes significantly higher superoxide radical (O2-) levels was detected in both Atgst mutants than in the Col-0 control. Salt treatment resulted in the highest O2- increase in the Atgstf8 root, while the amount of H2O2 elevated most in the case of Atgstu19. Moreover, vitality decreased in Atgstu19 roots more than in wild type under salt stress. Our results indicate that AtGSTF8 and especially the AtGSTU19 proteins function in the root fine-tuning the redox homeostasis both under control and salt stress conditions.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/fisiologia , Glutationa Transferase/fisiologia , Meristema/fisiologia , Raízes de Plantas/fisiologia , Arabidopsis/enzimologia , Arabidopsis/metabolismo , Homeostase , Peróxido de Hidrogênio/metabolismo , Meristema/metabolismo , Oxirredução , Raízes de Plantas/enzimologia , Raízes de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Estresse Salino , Superóxidos/metabolismo
7.
Chemosphere ; 230: 544-558, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31125883

RESUMO

Plant growth and development could be modulated by minute concentrations of hydrogen peroxide (H2O2) which serves as a signaling molecule for various processes. The present work was conducted with an aim that H2O2 could also modify root morphology, morphology and movement of stomata, photosynthetic responses, activity of carbonic anhydrase, and antioxidant systems in tomato (Solanum lycopersicum L.) plants under copper stress (Cu; 10 or 100 mg kg-1 soil). Roots of 20 d old plants were dipped in 0.1 or 0.5 mM of H2O2 solution for 4 h and then transplanted to the soil filled in earthen pots. High Cu stress (100 mg kg-1 soil) altered root morphology, reduced chlorophyll content and photosynthetic capacity and also affected movement of stomata and generation of antioxidant species at 40 d after transplantation. Further, root dipping treatment of H2O2 to plants under stress and stress-free conditions enhanced accumulation of proline and activity of catalase, peroxidase, and superoxide dismutase, whereas production of superoxide radical (O2•¯) and H2O2 were decreased. Overall, H2O2 treatment improved growth, photosynthesis, metabolic state of the plants which provided tolerance and helped the plants to cope well under Cu stress.


Assuntos
Antioxidantes/metabolismo , Cobre/toxicidade , Peróxido de Hidrogênio/farmacologia , Lycopersicon esculentum/crescimento & desenvolvimento , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Poluentes do Solo/toxicidade , Lycopersicon esculentum/enzimologia , Lycopersicon esculentum/metabolismo , Raízes de Plantas/enzimologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo
8.
Int J Mol Sci ; 20(8)2019 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-31010077

RESUMO

Purple acid phosphatase (PAP) encoding genes are a multigene family. PAPs require iron (Fe) to exert their functions that are involved in diverse biological roles including Fe homeostasis. However, the possible roles of PAPs in response to excess Fe remain unknown. In this study, we attempted to understand the regulation of PAPs by excess Fe in tea plant (Camellia sinensis). A genome-wide investigation of PAP encoding genes identified 19 CsPAP members based on the conserved motifs. The phylogenetic analysis showed that PAPs could be clustered into four groups, of which group II contained two specific cysteine-containing motifs "GGECGV" and "YERTC". To explore the expression patterns of CsPAP genes in response to excessive Fe supply, RNA-sequencing (RNA-seq) analyses were performed to compare their transcript abundances between tea plants that are grown under normal and high iron conditions, respectively. 17 members were shown to be transcribed in both roots and leaves. When supplied with a high amount of iron, the expression levels of four genes were significantly changed. Of which, CsPAP15a, CsPAP23 and CsPAP27c were shown as downregulated, while the highly expressed CsPAP10a was upregulated. Moreover, CsPAP23 was found to be alternatively spliced, suggesting its post-transcriptional regulation. The present work implicates that some CsPAP genes could be associated with the responses of tea plants to the iron regime, which may offer a new direction towards a further understanding of iron homeostasis and provide the potential approaches for crop improvement in terms of iron biofortification.


Assuntos
Fosfatase Ácida/genética , Camellia sinensis/enzimologia , Glicoproteínas/genética , Ferro/metabolismo , Proteínas de Plantas/genética , Fosfatase Ácida/classificação , Fosfatase Ácida/metabolismo , Sequência de Aminoácidos , Camellia sinensis/genética , Genes de Plantas , Glicoproteínas/classificação , Glicoproteínas/metabolismo , Família Multigênica , Filogenia , Folhas de Planta/enzimologia , Folhas de Planta/genética , Proteínas de Plantas/classificação , Proteínas de Plantas/metabolismo , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Processamento de RNA , Alinhamento de Sequência , Transcriptoma
9.
Science ; 364(6435): 57-62, 2019 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-30948546

RESUMO

Rho guanosine triphosphatases (GTPases) are master regulators of cell signaling, but how they are regulated depending on the cellular context is unclear. We found that the phospholipid phosphatidylserine acts as a developmentally controlled lipid rheostat that tunes Rho GTPase signaling in Arabidopsis Live superresolution single-molecule imaging revealed that the protein Rho of Plants 6 (ROP6) is stabilized by phosphatidylserine into plasma membrane nanodomains, which are required for auxin signaling. Our experiments also revealed that the plasma membrane phosphatidylserine content varies during plant root development and that the level of phosphatidylserine modulates the quantity of ROP6 nanoclusters induced by auxin and hence downstream signaling, including regulation of endocytosis and gravitropism. Our work shows that variations in phosphatidylserine levels are a physiological process that may be leveraged to regulate small GTPase signaling during development.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Arabidopsis/crescimento & desenvolvimento , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Fosfatidilserinas/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Membrana Celular/química , Membrana Celular/metabolismo , Endocitose/genética , Regulação da Expressão Gênica de Plantas , Gravitropismo/genética , Ácidos Indolacéticos/metabolismo , Proteínas Monoméricas de Ligação ao GTP/genética , Fosfatidilserinas/farmacologia , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Transdução de Sinais , Imagem Individual de Molécula
10.
Microb Pathog ; 130: 71-80, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30844473

RESUMO

Mandacaru (Cereus jamacaru DC.), is a cactaceous symbol of caatinga vegetation at Brazilian Northeast region, however, there are no much studies about biochemical properties of this species. Here, the pioneering study brings very relevant data to highlight the importance of research with endemic plants of the caatinga. Afterward, the presence of enzymes such as peroxidase, protease, chitinase, ß-1,3-glucanase, and serine (trypsin) and cysteine (papain) protease inhibitors were evaluated. The peroxidase activity was higher in roots than other tissues. The ß-1,3-glucanase and proteolytic activity were prominent in stem and roots. The chitinase activity and protease inhibitor for both classes analyzed were detected in the stem and fruit peel. Antifungal activity against Colletotrichum gloeosporioides showed the root extract has a promising inhibitory activity on this economical important phytopathogenic fungus. After the contact of the hyphae with root extract increase in membrane permeability, based on Propidium Iodide (PI) uptake, and production of reactive oxygen species (ROS) were detected, compared to negative control. In addition, Scanning Electron Microscopy (SEM) analysis showed morphological damage on hyphae structure indicating that the treatment debilitates either cell membrane or cell wall leading to the cell death C. gloeosporioides.


Assuntos
Antifúngicos/farmacologia , Cactaceae/química , Membrana Celular/efeitos dos fármacos , Membrana Celular/patologia , Colletotrichum/crescimento & desenvolvimento , Proteínas de Plantas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Antifúngicos/isolamento & purificação , Cactaceae/enzimologia , Colletotrichum/efeitos dos fármacos , Colletotrichum/enzimologia , Colletotrichum/ultraestrutura , Enzimas/análise , Frutas/química , Frutas/enzimologia , Hifas/ultraestrutura , Viabilidade Microbiana/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Permeabilidade/efeitos dos fármacos , Proteínas de Plantas/isolamento & purificação , Raízes de Plantas/química , Raízes de Plantas/enzimologia , Caules de Planta/química , Caules de Planta/enzimologia
11.
Plant Sci ; 280: 314-320, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30824010

RESUMO

The 26S proteasome is a multi-subunit protease controlling most of the cytosolic and nuclear protein turnover, regulating many cellular events in eukaryotes. However, functional modification on this complex remains unclear. Here, we showed a novel mechanism that a SUMO ligase AtMMS21 regulates activity of the 26S proteasome in root development of Arabidopsis. Our in vitro and in vivo data supported that AtMMS21 interacts with RPT2a, a subunit of the 26S proteasome. The mutants of AtMMS21 and RPT2a display similar developmental defect of roots, suggesting their association in this process. In addition, RPT2a is modified by SUMO3, potentially related to AtMMS21. During development, the activity of the 26S proteasome is lower in both mutants of AtMMS21 and RPT2a, compared with that of wild type. Furthermore, the protein level but not the RNA level of RPT2a is decreased in the absence of AtMMS21, implying stability regulation of the proteasome complex through the AtMMS21-RPT2a interaction. Taken together, the current study would improve our understanding on the regulatory mechanism of the 26S proteasome via protein modification in root development.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Ligases/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Ligases/genética , Mutação , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Complexo de Endopeptidases do Proteassoma/genética , Sumoilação
12.
Plant Physiol Biochem ; 136: 245-254, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30710774

RESUMO

Roots of the higher plants can assimilate inorganic nitrogen by an enzymatic reduction of the most oxidized form (+6) nitrate to the reduced form (-2) glutamate. For such reactions, the substrates (originated from photosynthates) must be imported to supply energy through the reductant-generating systems within the root cells. Intensive studies over last 70 years (reviewed here) revealed the precise mechanisms of nitrate-to-glutamate transformation in roots with elaborate searches of 15N-tracing, enzymes involved, the reductant-supplying system, and nitrate signaling. In the 1970s, the tracing of 15N-labeled nitrate and ammonia in the roots demonstrated the sequential reduction and assimilation of nitrate to nitrite, ammonia, glutamine amide, and then glutamate. These reactions involve nitrate reductase (NADH-NR, EC 1.7.1.1) in the cytosol, nitrite reductase (ferredoxin [Fd]-NiR, EC 1.7.7.1), glutamine synthetase (GS2, EC 6.3.1.2), and glutamate synthase (Fd-GOGAT, EC 1.4.7.1) in the plastids. NADH for NR is generated by glycolysis in the cytosol, and NADPH for Fd-NIR and Fd-GOGAT are produced by the oxidative pentose phosphate pathway (OPPP). Electrons from NADPH are conveyed to reduce NIR and Fd-GOGAT through Fd-NADP+ reductase (FNR, EC 1.6.7.1) specifically in the roots. Physiological and molecular analyses showed the parallel inductions of NR, NIR, GS2, Fd-GOGAT, OPPP enzymes, FNR, and Fd in response to a short-term nitrate supply. Recent studies proposed a molecular mechanism of nitrate-induction of these genes and proteins. Roots can also assimilate the reduced form of inorganic ammonia by the combination of cytosolic GS1 and plastidic NADH-GOGAT.


Assuntos
Glutamatos/metabolismo , Nitratos/metabolismo , Raízes de Plantas/metabolismo , Plantas/metabolismo , Isótopos de Nitrogênio/metabolismo , Raízes de Plantas/enzimologia , Plantas/enzimologia , Transdução de Sinais
13.
Chemosphere ; 222: 399-406, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30711729

RESUMO

Nickel contamination may lead to the destruction of food, ecological safety and its toxicity to plants remains to be studied in depth. In our present study, the translocation factors (TFsoil to root and TFroot to shoot) revealed a significant logarithmic decline with the increase of Ni exposure. In lettuce roots, NiHAC played an important protective role against high Ni stress and the ratio of Ni with high activity (NiE and NiW) in root decreased with the addition of Ni. The activities of antioxidant enzymes (CAT, POD and SOD) in the lettuce roots were increased and might be the way for lettuce to adapt Ni stress. CAT and POD can be great indicators of Ni pollution exhibiting better dose-effect relationships with Ni. Under high Ni stress, lettuce roots contained higher levels of MDA suffering greater pressure than shoots. Expression levels of gene GST 23-like indicated a remarkable (P < 0.05) down-regulation and then this trend would be alleviated after high Ni exposure, and it was positively correlated with GST concentrations (R2 = 0.704). We believe that our research would open up the new avenues for effective understanding ecological risks of Ni.


Assuntos
Tolerância a Medicamentos , Alface/efeitos dos fármacos , Níquel/farmacologia , Antioxidantes/metabolismo , Raízes de Plantas/enzimologia , Solo/química , Poluentes do Solo/farmacologia , Estresse Fisiológico
14.
Microbiol Res ; 220: 42-52, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30744818

RESUMO

Contamination of soil by textile effluent is a major threat found worldwide. These pollutants have diverse range of negative effects on the ecosystem, therefore restoration through cost effective biological strategy is the need of the hour. The aim of the current study was to enhance the decolourization of reactive green dye (RGD) using phytoremediation coupled with augmentation of effective bacteria to the rhizosphere. The isolate Klebsiella sp. VITAJ23 was isolated from textile effluent polluted soil and was assessed for its plant growth promoting traits (PGP) and the PGP functional genes were amplified. The soil was artificially polluted with RGD concentration ranging from 1000 to 3000 mg kg-1 and Alternanthera philoxeroides plantlets were planted in phyto and rhizoremediation treatments, the setup was maintained upto 60 d. The isolate VITAJ23 was augmented in the rhizoremediation setup and the morphological parameters were assessed at regular interval. There was a significant increase in the chlorophyll content as well as root and shoot length of the plant when treated with the bacterial suspension. Decolourization study revealed 79% removal of reactive green dye with an enhanced oxido-reductase enzyme activity in the setup bioaugmented with bacteria. The biodegraded metabolites were identified as 2-allylnapthalene, l-alanine, n-acetyl-and propenoic acid by GC-MS analysis and a plant-bacteria degradation pathway was predicted using computational tools. Inoculation of PGP-Klebsiella sp. VITAJ23 enhanced the rate of plant growth and dye degradation.


Assuntos
Amaranthaceae/metabolismo , Corantes/metabolismo , Klebsiella/fisiologia , Desenvolvimento Vegetal , Amaranthaceae/enzimologia , Amaranthaceae/genética , Amaranthaceae/microbiologia , Biodegradação Ambiental , Clorofila , Recuperação e Remediação Ambiental , Klebsiella/isolamento & purificação , Raízes de Plantas/enzimologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Rizosfera , Solo/química , Microbiologia do Solo , Poluentes do Solo/metabolismo , Indústria Têxtil , Poluentes Químicos da Água/metabolismo
15.
Molecules ; 24(3)2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30717241

RESUMO

Theanine, a unique amino acid in Camellia sinensis, accounts for more than 50% of total free amino acids in tea and has a significant contribution to the quality of green tea. Previous research indicated that theanine is synthesized from glutamic acid (Glu) and ethylamine mainly in roots, and that theanine accumulation depends on the availability of ethylamine which is derived from alanine (Ala) decarboxylation catalyzed by alanine decarboxylase (AlaDC). However, the specific gene encoding AlaDC protein remains to be discovered in tea plants or in other species. To explore the gene of AlaDC in tea plants, the differences in theanine contents and gene expressions between pretreatment and posttreatment of long-time nitrogen starvation were analyzed in young roots of two tea cultivars. A novel gene annotated as serine decarboxylase (SDC) was noted for its expression levels, which showed high consistency with theanine content, and the expression was remarkably high in young roots under sufficient nitrogen condition. To verify its function, full-length complementary DNA (cDNA) of this candidate gene was cloned from young roots of tea seedlings, and the target protein was expressed and purified from Escherichia coli (E. coli). The enzymatic activity of the protein for Ala and Ser was measured in vitro using ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS). The results illustrated that the target protein could catalyze the decarboxylation of Ala despite of its high similarity with SDC from other species. Therefore, this novel gene was identified as AlaDC and named CsAlaDC. Furthermore, the gene expression levels of CsAlaDC in different tissues of tea plants were also quantified with quantitative real-time PCR (qRT-PCR). The results suggest that transcription levels of CsAlaDC in root tissues are significantly higher than those in leaf tissues. That may explain why theanine biosynthesis preferentially occurs in the roots of tea plants. The expression of the gene was upregulated when nitrogen was present, suggesting that theanine biosynthesis is regulated by nitrogen supply and closely related to nitrogen metabolism for C. sinensis. The results of this study are significant supplements to the theanine biosynthetic pathway and provide evidence for the differential accumulation of theanine between C. sinensis and other species.


Assuntos
Alanina/metabolismo , Camellia sinensis/genética , Carboxiliases/genética , Regulação da Expressão Gênica de Plantas , Glutamatos/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/genética , Camellia sinensis/enzimologia , Carboxiliases/metabolismo , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Etilaminas/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Nitrogênio/deficiência , Nitrogênio/farmacologia , Especificidade de Órgãos , Filogenia , Folhas de Planta/enzimologia , Folhas de Planta/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/enzimologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Plântula/enzimologia , Plântula/genética , Serina/metabolismo , Chá
16.
Ecotoxicol Environ Saf ; 171: 823-832, 2019 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-30660976

RESUMO

Various nitrate and ammonium proportions (NO3-/NH4+) in the growth media can increase metal phytoextraction compared to supplying solely NO3-. However, there are no studies showing these effects in plants under copper (Cu) contamination as well as their consequences in plant stress tolerance. The objective was to evaluate the effect of NO3-/NH4+ proportions in Cu phytoextraction by Panicum maximum cv. Tanzania and its consequence in the oxidative stress, photosynthesis, and antioxidant system under Cu stress. The experiment was carried out in a randomized complete block design, by using a 3 × 4 factorial with six replications. Three NO3-/NH4+ proportions (100/0, 70/30, and 50/50) were combined with four Cu rates (0.3, 250, 500, and 1000 µmol L-1) in the nutrient solution. It was found that the largest Cu accumulation in the shoots occurred at the first harvest of the plants supplied with 70/30 NO3-/NH4+ and Cu 1000 µmol L-1. Such plants also displayed high concentrations of proline in the shoots as well as high superoxide dismutase activity in the roots. Malondialdehyde concentration was high in the plant parts at the Cu rate of 1000 µmol L-1. Hence, transpiration rates, stomatal conductance, quantum efficiency of photosystem II, electron transport rate, and net photosynthesis were all low at the Cu rate of 1000 µmol L-1. Catalase, guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase activities in the roots were high when plants were exposed to Cu 1000 µmol L-1. In conclusion, the combination of NO3- with NH4+ increases copper phytoextraction that causes oxidative stress, but also favors the antioxidant system of Tanzania guinea grass in attempt to tolerate such stress.


Assuntos
Compostos de Amônio , Antioxidantes/metabolismo , Cobre/farmacocinética , Poluentes Ambientais/farmacocinética , Nitratos , Panicum/metabolismo , Ascorbato Peroxidases/metabolismo , Biodegradação Ambiental , Catalase/metabolismo , Cobre/toxicidade , Poluentes Ambientais/toxicidade , Glutationa Redutase/metabolismo , Malondialdeído/metabolismo , Estresse Oxidativo , Panicum/efeitos dos fármacos , Panicum/enzimologia , Peroxidase/metabolismo , Fotossíntese/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Distribuição Aleatória , Tanzânia
17.
Phytochemistry ; 159: 137-147, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30611873

RESUMO

Stilbene phytoalexins derived from grapevine can be rapidly accumulated when exposed to an artificial UV-C treatment. However, the underlying mechanisms involved in this accumulation and translocation are unclear. Here, we describe an investigation of the influence of UV-C treatment on the dynamic subcellular distribution of a member of a stilbene synthase family VpSTS29 derived from Chinese wild Vitis pseudoreticulata W.T. Wang when over-expressed in V. vinifera L. cv. Thompson Seedless. Our results show that VpSTS29-GFP was accumulated at a relatively high level in roots and mature leaves of transgenic grape lines, and was predominantly distributed in the cytoplasm. When exposed to UV-C irradiation, VpSTS29 displayed UV-induced feature coupled with the accumulation of stilbene compounds. Notably, VpSTS29-GFP can be translocated from the cytoplasm into chloroplasts upon UV-irradiation. Leaves from the two VpSTS29-GFP-expressing lines displayed more serious UV damage, showing withering and marginal scorching phenotype, and decreased content of H2O2, compared to the untransformed plant. Also, overexpression of VpSTS29 altered the expression of genes related to redox regulation, stilbene biosynthesis and light stimulus. Co-expression of VpSTS29-GFP with Glycolate oxidase 1 (myc-VpGLO1) confirmed the ability of stilbenes to decrease the content of H2O2 in Arabidopsis mesophyll protoplasts. These results provide new insight into the biological functions and properties of stilbene synthase and its product in response to environmental stimulus.


Assuntos
Aciltransferases/metabolismo , Raios Ultravioleta , Vitis/efeitos da radiação , Aciltransferases/genética , Citosol/enzimologia , Regulação para Baixo , Oxirredução , Estresse Oxidativo/efeitos da radiação , Folhas de Planta/enzimologia , Raízes de Plantas/enzimologia , Plantas Geneticamente Modificadas , Transporte Proteico , Estilbenos/metabolismo , Vitis/enzimologia
18.
J Plant Physiol ; 232: 115-126, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30537598

RESUMO

Lignans are diphenolic compounds produced in plants via coupling of two coniferyl alcohol molecules with the aid of a dirigent protein to form pinoresinol (PINO). The latter is reduced via lariciresinol (LARI) to secoisolariciresinol by the bifunctional pinoresinol-lariciresinol reductase (PLR). In this study, we clarified the consequences of altered lignan biosynthesis on amino acids, phenolics compounds and lignin in the hairy roots of Linum album with an ihpRNAi construct to silence PLR gene expression. Down-regulation of PLR-La1 resulted in up to an 8.3 and 3.3-time increased PINO and LARI content respectively, and reduced levels of podophyllotoxin (PTOX) and 6-methoxy podophyllotoxin (6-MPTOX). By Suppression of PLR expression, the metabolites belonging to shikimate and phenylpropanoid pathways are conducted to phenolic compounds and lignin accumulations. Although PINO and LARI were induced in response to fungal elicitor, the accumulation of PTOX and 6-MPTOX did not occur in PLR down-regulated roots. Our result also demonstrated variation in amino acids, phenolic compounds and lignin levels in presence of the fungal elicitation in PLR down regulated-roots. This data assert the accumulation of aryltetralin lignans in interactions with plant pathogens by PLR activity and the importance this enzyme for defense against pathogens in L. album.


Assuntos
Linho/fisiologia , Oxirredutases/metabolismo , Doenças das Plantas/microbiologia , Proteínas de Plantas/metabolismo , Raízes de Plantas/fisiologia , Interferência de RNA , Linho/enzimologia , Linho/genética , Linho/microbiologia , Inativação Gênica/fisiologia , Genes de Plantas/genética , Redes e Vias Metabólicas , Micorrizas/metabolismo , Oxirredutases/genética , Oxirredutases/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/fisiologia , Raízes de Plantas/enzimologia , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Interferência de RNA/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de DNA
19.
Sci Total Environ ; 651(Pt 1): 84-92, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30223222

RESUMO

Methane (CH4) is predominantly produced in lowland rice soil, but its emission from soil to atmosphere primarily depends on passage/conduit or capillary pore spaces present in rice plants. The gas transport mechanism through aerenchyma pore spaces of rice cultivars was studied to explore the plant mediated CH4 emission. Seven rice cultivars, based on the life cycle duration (LCD), were tested in tropical eastern India. Three LCD groups were, (a) Kalinga 1 and CR Dhan 204 (LCD: 110-120 days); (b) Lalat, Pooja and CR 1014 (LCD: 130-150 days); and (c) Durga and Varshadhan (LCD: 160-170 days). Rate of CH4emission, root exudates, root oxidase activities and shoot aerenchyma pore spaces were analyzed to study the mechanism of plant mediated emission from rice. Aerenchyma pore space was quantified in the hypothesis that it regulates the CH4 transportation from soil to atmosphere. The ratio of pore space area to total space was lowest in Kalinga 1 cultivar (0.29) and highest was in Varshadhan (0.43). Significant variations in the methane emission were observed among the cultivars with an average emission rate ranged from 0.86 mg m-2 h-1 to 4.96 mg m-2 h-1. The CH4 emission rates were lowest in short duration cultivars followed by medium and long duration ones. The greenhouse gas intensity considering average CH4 emission rate per unit grain yield was also lowest (0.35) in Kalinga 1 and relatively less in short and medium duration cultivars. Root exudation was higher at panicle initiation (PI) than maximum tillering (MT) stage. Lowest exudation was noticed in (197.2 mg C plant-1 day-1) Kalinga 1 and highest in Varsadhan (231.7 mg C plant-1 day-1). So we can say, the rate of CH4 emission was controlled by aerenchyma orientation, root exudation and biomass production rate which are the key specific traits of a cultivar. Identified traits were closely associated with duration and adaptability to cultivars grown in specific ecology. Therefore, there is possibility to breed rice cultivars depending on ecology, duration and having less CH4 emission potential, which could be effectively used in greenhouse gas mitigation strategies.


Assuntos
Poluentes Atmosféricos/metabolismo , Metano/metabolismo , Oryza/metabolismo , Índia , Oryza/anatomia & histologia , Oryza/genética , Raízes de Plantas/enzimologia , Raízes de Plantas/metabolismo , Clima Tropical
20.
Acta Biol Hung ; 69(4): 437-448, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30587015

RESUMO

Hyoscyamus reticulatus L. is a herbaceous biennial belonging to the solanaceae family. Hyoscyamine and scopolamine as main tropane alkaloids accumulated in henbane are widely used in medicine to treat diseases such as parkinson's or to calm schizoid patients. Hairy roots media manipulation which uses elicitors to activate defense mechanisms is one of the main strategies for inducing secondary metabolism as well as increasing the production of valuable metabolites. Cotyledon-derived hairy root cultures were transformed by Agrobacterium rhizogenes. Sodium nitroprusside (SNP), a nitric oxide donor), was used in various concentrations (0, 50, 100, 200 and 300 µM) and exposure times (24 and 48 h). Treatment with SNP led to a significant reduction in fresh and dry weight of hairy roots, compared to control cultures. ANOVA results showed that elicitation of hairy root cultures with SNP at different concentrations and exposure times significantly affected the activity of as antioxidant enzymes such as catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX). The highest hyoscyamine and scopolamine production (about 1.2-fold and 1.5-fold increases over the control) was observed at 50 and 100 µM SNP at 48 and 24 hours of exposure time, respectively. This is the first report of SNP elicitation effects on the production of tropane alkaloids in hairy root cultures.


Assuntos
Antioxidantes/metabolismo , Enzimas/biossíntese , Hyoscyamus/efeitos dos fármacos , Doadores de Óxido Nítrico/farmacologia , Nitroprussiato/farmacologia , Proteínas de Plantas/biossíntese , Raízes de Plantas/efeitos dos fármacos , Tropanos/metabolismo , Agrobacterium/genética , Agrobacterium/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Relação Dose-Resposta a Droga , Indução Enzimática , Hyoscyamus/enzimologia , Hyoscyamus/crescimento & desenvolvimento , Hyoscyamus/microbiologia , Raízes de Plantas/enzimologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Fatores de Tempo , Técnicas de Cultura de Tecidos , beta-Glucosidase/genética , beta-Glucosidase/metabolismo
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