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1.
Ecotoxicol Environ Saf ; 203: 111010, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888587

RESUMO

Manganese (Mn) toxicity is common in plants grown on very acid soils. However, some plants species that grow in this condition can take up high amounts of Mn and are referred to as hyperaccumulating species. In this study, we evaluated the capacity of Ilex paraguariensis to accumulate Mn and the effect of excessive concentrations on plant growth and nutrition. For this, a container experiment was conducted using soils from different parent materials (basalt and sandstone), with and without liming, and at six doses of applied Mn (0, 30, 90, 270, 540 and 1,080 mg kg-1). Clonal plants grown for 203 days were harvested to evaluate yield, and leaf tissue samples were evaluated for Mn and other elements. Without liming and with high Mn doses, leaf Mn concentrations reached 13,452 and 12,127 mg kg-1 in sandstone and basalt soils, respectively; concentrations in excess of 10,000 mg kg-1 are characteristic of hyperaccumulating plants. Liming reduced these values to 7203 and 8030 mg kg-1. More plant growth accompanied increased Mn leaf concentrations, with a growth reduction noted at the highest dose in unlimed soils. Elemental distribution showed Mn presence in the mesophyll, primarily in vascular bundles, without high Mn precipitates. Interveinal chlorosis of young leaves associated with high Mn concentration and lower Fe concentrations was observed, especially in sandstone soil without liming. However, the occurrence of this symptom was not associated with decreased plant growth.


Assuntos
Ácidos/farmacologia , Ilex paraguariensis/metabolismo , Manganês/metabolismo , Doenças das Plantas/induzido quimicamente , Poluentes do Solo/metabolismo , Ácidos/análise , Compostos de Cálcio/análise , Compostos de Cálcio/farmacologia , Ilex paraguariensis/efeitos dos fármacos , Ilex paraguariensis/crescimento & desenvolvimento , Ferro/metabolismo , Manganês/análise , Manganês/toxicidade , Óxidos/análise , Óxidos/farmacologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Solo/química , Poluentes do Solo/análise , Poluentes do Solo/toxicidade
2.
Ecotoxicol Environ Saf ; 205: 111298, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32950806

RESUMO

Mulberry (Morus atropurpurea) is an economically important woody tree and has great potential for the remediation of heavy metals. To investigate how cadmium accumulates and its detoxification in mulberry, we assessed the physiological and transcriptomic effects of cadmium contamination and as well as its chemical forms and subcellular distribution. Cadmium significantly inhibited mulberry plant growth and primarily accumulated in mulberry roots. Antioxidant enzymes were induced by cadmium in all tissues of mulberry. Subcellular fractionation analyses of cadmium indicated that the majority was compartmentalized in soluble fraction in roots while it mainly located in cell wall in leaves and stems. The greatest amount of the cadmium was integrated with proteins and pectates in all mulberry tissues. RNA-seq transcriptomic analyses of mulberry roots revealed that various metabolic pathways involved in cadmium stress response such as RNA regulation, hormone metabolism, and response to stress, secondary metabolism, as well as signaling, protein metabolism, transport, and cell-wall metabolism. These results will increase our understanding of the molecular mechanisms of cadmium detoxification in mulberry and provide new insights into engineering woody plants for phytoremediation.


Assuntos
Bioacumulação , Cádmio/toxicidade , Morus/efeitos dos fármacos , Poluentes do Solo/toxicidade , Estresse Fisiológico/efeitos dos fármacos , Transcriptoma/efeitos dos fármacos , Biodegradação Ambiental , Cádmio/metabolismo , Perfilação da Expressão Gênica , Morus/crescimento & desenvolvimento , Morus/metabolismo , 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 , Poluentes do Solo/metabolismo , Estresse Fisiológico/genética
3.
Ecotoxicol Environ Saf ; 203: 111019, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888606

RESUMO

Sulfur dioxide (SO2) is one of the most common and harmful air pollutants. High concentrations of SO2 can induce a series of defensive responses in Arabidopsis plants. However, the role of photosynthesis in the plant response to SO2 stress is not clear. Here, we report the photosynthetic responses of Arabidopsis plants to SO2 stress. Exposure to 30 mg/m3 SO2 decreased stomatal conductance (Gs) and transpiration rate (Tr) but increased photosynthetic pigments and net photosynthetic rate (Pn). The contents of carbohydrates and sucrose were not altered. The transcript levels of most genes related to photosystem II (PSII), cytochrome b6/f (Cytb6f), photosystem I (PSI) and carbon fixation were upregulated, revealing one important regulatory circuit for the maintenance of chloroplast homeostasis under SO2 stress. Exposure to SO2 triggered reactive oxygen species (ROS) generation, accompanied by increases in superoxide dismutase (SOD) activity and the contents of cysteine (Cys), glutathione (GSH) and non-protein thiol (NPT), which maintained cellular redox homeostasis. Together, our results indicated that chloroplast photosynthesis was involved in the plant response to SO2 stress. The photosynthetic responses were related to photosynthetic pigments, photosynthesis gene expression and redox regulation.


Assuntos
Poluentes Atmosféricos/toxicidade , Arabidopsis/efeitos dos fármacos , Expressão Gênica/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Pigmentos Biológicos/metabolismo , Dióxido de Enxofre/toxicidade , Arabidopsis/genética , Arabidopsis/metabolismo , Cloroplastos/metabolismo , Regulação para Baixo , Fotossíntese/genética , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Regulação para Cima
4.
PLoS One ; 15(9): e0236577, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32941459

RESUMO

Winter rapeseed (Brassica rapa L.) is the main oilseed crop in northern China and can safely overwinter at 35 (i.e., Tianshui, China) to 48 degrees north latitude (i.e., Altai, Heilongjiang, Raohe, and Xinjiang, China). In order to identify stable reference genes to understand the molecular mechanisms of stress tolerance in winter rapeseed, internal reference genes of winter rapeseed under four abiotic stresses were analyzed using GeNorm, NormFinder, BestKeeper, and RefFinder software. The most stable combinations of internal reference genes were ß-actin and SAND in cold-stressed leaves, ß-actin and EF1a in cold-stressed roots, F-box and SAND in high temperature-stressed leaves, and PP2A and RPL in high temperature-stressed roots, SAND and PP2A in NaCl-stressed leaves, RPL and UBC in NaCl-stressed roots, RPL and PP2A in PEG-stressed leaves, and PP2A and RPL in PEG-stressed roots. Expression profiles of PXG3 were used to verify these results. The stable reference genes identified in this study are useful tools for identifying stress-responsive genes to understand the molecular mechanisms of stress tolerance in winter rapeseed.


Assuntos
Brassica rapa/genética , Resposta ao Choque Frio , Perfilação da Expressão Gênica/normas , Pressão Osmótica , Proteínas de Plantas/genética , Brassica rapa/metabolismo , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Padrões de Referência , Estações do Ano
5.
Ecotoxicol Environ Saf ; 205: 111323, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32956864

RESUMO

Using an ideal parental line to breed hybrid rice with low cadmium (Cd) accumulation in grain is an environmental-friendly approach to reduce the risk of Cd contamination in field. A grain low-Cd rice line YaHui2816 has stably low Cd in grain but strong Cd accumulation in straw, revealing specific pattern of its straw-grain Cd remobilization is beneficial to effectively breed hybrid rice for safe production as well as phytoremediation. In this study, a pot experiment was conducted to investigate Cd partitioning of YaHui2816 at different stages by comparison with a common rice C268A. The Cd from lower nodes and leaves was restricted in nodeⅡ, this Cd retention led to weak Cd transport from straw to ear in YaHui2816. Cd concentration in nodeⅡ of YaHui2816 was 1.56-fold and 7.36-fold higher than C268A at filling and mature stages. Thus, glutathione (GSH) and phytochelatin (PC) concentration, PC synthase (OsPCS1), GSH S-Transferase (OsGST) and Cd-remobilization associated genes were measured at filling stage. OsHMA2 and OsCCX2 were up-regulated in nodeⅡ of YaHui2816, relative expression of them were significantly higher than C268A. PCs participated in Cd remobilization process, remarkable PC increase in nodeⅡ of YaHui2816 was found in response to Cd treatment under regulation of OsPCS1 and OsGST of which PC2 was dominant form. Taken as a whole, the Cd retention in nodeⅡ of YaHui2816 acts as a 'firewall' to restrain Cd transport to grain. This work provides more insight to understand possible function of alleles for reducing Cd concentration in grain as well as strengthening Cd accumulation in straw of YaHui2816.


Assuntos
Cádmio/metabolismo , Oryza/fisiologia , Poluentes do Solo/metabolismo , Aminoaciltransferases , Grão Comestível/química , Oryza/metabolismo , Fitoquelatinas/metabolismo , Folhas de Planta/metabolismo , Poluentes do Solo/análise
6.
Ecotoxicol Environ Saf ; 205: 111350, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32961487

RESUMO

Atmospheric nitrogen dioxide (NO2) negatively affects plant (crop) growth and development, as well the yield and quality in some regions or environments. Arbuscular mycorrhizal fungus (AMF)-mediated amelioration of NO2-induced plant damage has been reported, but the underlying mechanisms remained unclear. This study explored the beneficial effect of AMF symbiosis on tomato plant responses to NO2 at physiology, biochemistry, and gene expression, with an emphasis on nitrate metabolism, antioxidative defense, and photosynthetic performance. Pot-grown plants were used in the experiments, which were performed in laboratory from February to November 2019. NO2 fumigation with a dose of 10 ± 1 ppm was carried out after 50 d of plant growth, and data were collected following 8 h of fumigation. NO2 fumigation (+NO2) and AMF inoculation (+AMF), alone and especially in combination (NO2 + AMF), increased the gene expression of nitrate- and nitrite reductase, and their enzymatic activity in leaves, such as by 61%, 27%, and 126% for the activity of nitrate reductase, and by 95%, 37%, and 188% for nitrite reductase, respectively, in +NO2, +AMF, and AMF + NO2 plants relative the control (-NO2, -AMF) levels. Following NO2 exposure, +AMF leaves displayed stronger activities of superoxide dismutase, peroxidase and catalase, and higher content of glutathione and ratio of its reduced form to oxidized form, as compared with -AMF ones. Correspondingly, lesser oxidative damage was detected in +AMF than in -AMF plants, as indicated by the contents of H2O2 and malondialdehyde, electrolyte leakage, also by in situ visualization for the formation of H2O2, superoxide anion, and dead cells. The increased antioxidative capacity in +AMF plants was correlated with enhanced expression of antioxidation-related genes. Exposure to NO2 substantially impaired photosynthetic processes in both + AMF and -AMF plants, but an obvious mitigation was observed in the former than in the latter. For example, the total chlorophyll, net photosynthetic rate, stomatal conductance, and ribulose-1,5-bisphosphate carboxylase activity were 18%, 27%, 26%, and 40% higher, respectively, in +AMF than in -AMF plants under NO2 stress. The differential photosynthetic performance was also revealed by chlorophyll fluorescence imaging. We analyzed the expression patterns of some genes related to photosynthesis and carbon metabolisms, and found that all of them exclusively presented a higher expression level in +AMF plants relative to -AMF ones under NO2 stress. Taken together, this study provided evidence that AMF symbiosis played a positively regulatory role in host plant responses to NO2, probably by increasing leaf nitrate metabolism and antioxidative defense, and maintaining the photosynthetic efficiency to some extent, wherein the transcription regulation might be a main target.


Assuntos
Lycopersicon esculentum/fisiologia , Micorrizas/fisiologia , Dióxido de Nitrogênio/toxicidade , Antioxidantes/metabolismo , Clorofila/metabolismo , Peróxido de Hidrogênio/metabolismo , Lycopersicon esculentum/metabolismo , Lycopersicon esculentum/microbiologia , Micorrizas/metabolismo , Oxirredução , Fotossíntese/fisiologia , Desenvolvimento Vegetal , Folhas de Planta/metabolismo
7.
Ecotoxicol Environ Saf ; 204: 111136, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32798755

RESUMO

High temperature can lead to increased production of excess light energy, thus reducing photosynthetic capacity in plants. Photosynthetic cyclic electron flow (CEF) in photosystem I (PSI) can effectively protect photosystems, but its physiological mechanism under high temperature is poorly understood. In this study, antimycin A (AA) and thenoyltrifluoroacetone (TTFA) were used to inhibit PGR5-and NDH-dependent CEF pathways, respectively, to reveal the photoprotective functions of CEF for PSII in tobacco leaves under high temperature stress (37 °C, HT). High temperatures caused decreases in maximal photochemistry efficiency (Fv/Fm) and damaged photosystem II (PSII) in tobacco leaves. Under AA inhibition of PGR5-dependent CEF, high temperature increased the fluorescence intensity of point O (Fo) in OJIP curves, i.e., the energy absorption per active reaction center (ABS/RC), the trapping rate of the reaction center (TRo/RC), and the electron transport efficiency per reaction center (ETo/RC) in tobacco leaves. High temperature induced an increase in the hydrogen peroxide content and a decrease in pigment content in tobacco leaves. Under the high temperature treatment, inhibition of PGR5-dependent CEF reduced the activities of the PSII reaction center significantly, destroyed the oxygen-evolving complex (OEC), and impeded photosynthetic electron transfer from PSII to the plastoquinone (PQ) pool in tobacco leaves. The TTFA treatment inhibited the NDH-dependent pathway under high temperature conditions, with the relative fluorescence intensity of point I (VI) decreased significantly, and the content of hydrogen peroxide and superoxide anion increased significantly. Additionally, Fo and the redox degree of the PSII donor side (Wk) increased, and pigment content decreased compared to the control, but with little change compared to high temperature treatment, indicating that the inhibition of the NDH-dependent pathway directly weakened the capacity of the PQ pool to lead to the accumulation of reactive oxygen species (ROS) in tobacco leaves. In conclusion, CEF alleviated damage to the photosynthetic apparatus in tobacco leaves by increasing PSII heat dissipation, reducing ROS production, and maintaining the stability of the PQ pool to accommodate photosynthetic electron flow.


Assuntos
Temperatura Alta , Fotossíntese/fisiologia , Complexo de Proteína do Fotossistema I/metabolismo , Tabaco/metabolismo , Clorofila/metabolismo , Transporte de Elétrons , Elétrons , Fluorescência , Oxirredução , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Temperatura , Tabaco/fisiologia
8.
PLoS One ; 15(7): e0236943, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735612

RESUMO

Halophyte Lobularia maritima LmSAP encodes an A20AN1 zinc-finger stress-associated protein which expression is up-regulated by abiotic stresses and heavy metals in transgenic tobacco. To deepen our understanding of LmSAP function, we isolated a 1,147 bp genomic fragment upstream of LmSAP coding sequence designated as PrLmSAP. In silico analyses of PrLmSAP revealed the presence of consensus CAAT and TATA boxes and cis-regulatory elements required for abiotic stress, phytohormones, pathogen, and wound responses, and also for tissue-specific expression. The PrLmSAP sequence was fused to the ß-glucuronidase (gusA) reporter gene and transferred to rice. Histochemical GUS staining showed a pattern of tissue-specific expression in transgenic rice, with staining observed in roots, coleoptiles, leaves, stems and floral organs but not in seeds or in the root elongation zone. Wounding strongly stimulated GUS accumulation in leaves and stems. Interestingly, we observed a high stimulation of the promoter activity when rice seedlings were exposed to NaCl, PEG, ABA, MeJA, GA, cold, and heavy metals (Al3+, Cd2+, Cu2+ and Zn2+). These results suggest that the LmSAP promoter can be a convenient tool for stress-inducible gene expression and is a potential candidate for crop genetic engineering.


Assuntos
Regulação da Expressão Gênica de Plantas/genética , Regiões Promotoras Genéticas , Plantas Tolerantes a Sal/genética , Estresse Fisiológico/genética , Dedos de Zinco/genética , Produtos Agrícolas/genética , Engenharia Genética , Glucuronidase/metabolismo , Metais Pesados/metabolismo , Especificidade de Órgãos , Oryza/genética , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Caules de Planta/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Tabaco/genética
9.
Ecotoxicol Environ Saf ; 205: 111145, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32846296

RESUMO

This study characterizes sunflower response to the levels of Cd encountered in moderately Cd-polluted soils. Two sunflower cultivars differing in their ability to sequestrate Cd in roots were exposed to low concentrations of Cd (0.5 nM or 100 nM) in hydroponics and sampled after 18 days (258 degree-days) when ten leaves were fully expanded. Plant growth, Cd uptake and partitioning among organs were monitored along with the ionomic (ICP-MS) and the metabolic (1H-NMR) composition of the xylem sap. Sunflower tolerance to Cd differed between the two cultivars. The cultivar with the highest ability to sequestrate Cd in roots (Kapllan) was more tolerant to Cd than the one with the lowest ability (ES RICA). The 23% penalization of plant growth observed at 100 nM in cultivar ES RICA was associated with reduced xylem loading fluxes of soluble sugars, perhaps pointing to disruption of carbohydrate metabolism. Retention of Cd in the stem was higher at 100 nM than at 0.5 nM in the Cd-sensitive cultivar ES RICA, which can be seen as a sunflower strategy to restrict the amount of Cd delivered to the leaves under Cd stress. No direct connection was found between the speciation of Cd in the xylem sap and the Cd translocation efficiency, although significant changes in the free ionic fraction of Cd were observed between the two cultivars at 0.5 nM. The relevance of these results in promoting the use of sunflower in phytomanagement of Cd-polluted soils is discussed.


Assuntos
Cádmio/metabolismo , Helianthus/metabolismo , Hidroponia , Transporte Biológico , Desenvolvimento Vegetal , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Xilema/metabolismo
10.
Nat Commun ; 11(1): 3847, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32737299

RESUMO

Reporter systems are routinely used in plant genetic engineering and functional genomics research. Most such plant reporter systems cause accumulation of foreign proteins. Here, we demonstrate a protein-independent reporter system, 3WJ-4 × Bro, based on a fluorescent RNA aptamer. Via transient expression assays in both Escherichia coli and Nicotiana benthamiana, we show that 3WJ-4 × Bro is suitable for transgene identification and as an mRNA reporter for expression pattern analysis. Following stable transformation in Arabidopsis thaliana, 3WJ-4 × Bro co-segregates and co-expresses with target transcripts and is stably inherited through multiple generations. Further, 3WJ-4 × Bro can be used to visualize virus-mediated RNA delivery in plants. This study demonstrates a protein-independent reporter system that can be used for transgene identification and in vivo dynamic analysis of mRNA.


Assuntos
Aptâmeros de Nucleotídeos/genética , Arabidopsis/genética , Brassica/genética , Engenharia Genética/métodos , RNA Mensageiro/genética , Tabaco/genética , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/metabolismo , Arabidopsis/metabolismo , Compostos de Benzil/química , Brassica/metabolismo , Fluorescência , Corantes Fluorescentes/química , Regulação da Expressão Gênica , Genes Reporter , Imidazolinas/química , Folhas de Planta/genética , Folhas de Planta/metabolismo , Plantas Geneticamente Modificadas , RNA Mensageiro/metabolismo , Tabaco/metabolismo , Transformação Genética
11.
Ecotoxicol Environ Saf ; 202: 110916, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800251

RESUMO

Selenium (Se) at low concentration is considered benefit element to plants. The range between optimal and toxic concentration of Se is narrow and varies among plant species. This study aimed to evaluate the phenotypic, physiological and biochemical responses of four rice genotypes (BRS Esmeralda, BRSMG Relâmpago, BRS Bonança and Bico Ganga) grown hydroponically treated with sodium selenate (1.5 mM L-1). Selenium treated plants showed a dramatically decrease of soluble proteins, chlorophylls, and carotenoids concentration, resulting in the visual symptoms of toxicity characterized as leaf chlorosis and necrosis. Selenium toxicity caused a decrease on shoot and root dry weight of rice plants. Excess Se increased the oxidative stress monitored by the levels of hydrogen peroxide and lipid peroxidation. The enzymatic antioxidant system (catalase, superoxide dismutase, and ascorbate peroxidase) increased in response to Se supply. Interestingly, primary metabolism compounds such as sucrose, total sugars, nitrate, ammonia and amino acids increased in Se-treated plants. The increase in these metabolites may indicate a defense mechanism for the osmotic readjustment of rice plants to mitigate the toxicity caused by Se. However, these metabolites were not effective to minimize the damages on phenotypic traits such as leaf chlorosis and reduced shoot and root dry weight in response to excess Se. Increased sugars profile combined with antioxidant enzymes activities can be an effective biomarkers to indicate stress induced by Se in rice plants. This study shows the physiological attributes that must be taken into account for success in the sustainable cultivation of rice in environments containing excess Se.


Assuntos
Oryza/fisiologia , Selênio/toxicidade , Poluentes do Solo/toxicidade , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Clorofila/metabolismo , Peróxido de Hidrogênio/metabolismo , Hidroponia , Peroxidação de Lipídeos , Oryza/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Folhas de Planta/metabolismo , Ácido Selênico/metabolismo , Superóxido Dismutase/metabolismo
12.
PLoS One ; 15(8): e0236879, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790676

RESUMO

Benign prostatic hyperplasia (BPH) is a progressive pathological condition associated with proliferation of prostatic tissues, prostate enlargement, and lower-urinary tract symptoms. However, the mechanism underlying the pathogenesis of BPH is unclear. The aim of this study was to investigate the protective effects of a combination of Stauntonia hexaphylla and Cornus officinalis (SC extract) on a testosterone propionate (TP)-induced BPH model. The effect of SC extract was examined in a TP-induced human prostate adenocarcinoma cell line. Male Sprague-Dawley rats were randomly divided into 5 groups (n = 6) for in vivo experiments. To induce BPH, all rats, except those in the control group, were administered daily with subcutaneous injections of TP (5 mg/kg) and orally treated with appropriate phosphate buffered saline/drugs (finasteride/saw palmetto/SC extract) for 4 consecutive weeks. SC extract significantly downregulated the androgen receptor (AR), prostate specific antigen (PSA), and 5α-reductase type 2 in TP-induced BPH in vitro. In in vivo experiments, SC extract significantly reduced prostate weight, size, serum testosterone, and dihydrotestosterone (DHT) levels. Histologically, SC extract markedly recovered TP-induced abnormalities and reduced prostatic hyperplasia, thereby improving the histo-architecture of TP-induced BPH rats. SC extract also significantly downregulated AR and PSA expression, as assayed using immunoblotting. Immunostaining revealed that SC extract markedly reduced the 5α-reductase type 2 and significantly downregulated the expression of proliferating cell nuclear antigen. In addition, immunoblotting of B-cell lymphoma 2 (Bcl-2) family proteins indicated that SC extract significantly downregulated anti-apoptotic Bcl-2 and markedly upregulated pro-apoptotic B cell lymphoma-associated X (Bax) expression. Furthermore, SC treatment significantly decreased the Bcl-2/Bax ratio, indicating induced prostate cell apoptosis in TP-induced BPH rats. Thus, our findings demonstrated that SC extract protects against BPH by inhibiting 5α-reductase type 2 and inducing prostate cell apoptosis. Therefore, SC extract might be useful in the clinical treatment of BPH.


Assuntos
Apoptose/efeitos dos fármacos , Colestenona 5 alfa-Redutase/química , Extratos Vegetais/farmacologia , Hiperplasia Prostática/prevenção & controle , Substâncias Protetoras/uso terapêutico , Inibidores de 5-alfa Redutase/química , Inibidores de 5-alfa Redutase/farmacologia , Inibidores de 5-alfa Redutase/uso terapêutico , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Colestenona 5 alfa-Redutase/metabolismo , Cornus/química , Cornus/metabolismo , Regulação para Baixo/efeitos dos fármacos , Humanos , Masculino , Extratos Vegetais/química , Extratos Vegetais/uso terapêutico , Folhas de Planta/química , Folhas de Planta/metabolismo , Antígeno Prostático Específico/sangue , Hiperplasia Prostática/etiologia , Substâncias Protetoras/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ranunculales/química , Ranunculales/metabolismo , Ratos , Ratos Sprague-Dawley , Propionato de Testosterona/efeitos adversos
13.
PLoS One ; 15(8): e0237173, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32845897

RESUMO

Gentian is an important ornamental flower in Japan. The corolla of the majority of cultivated Japanese gentians have green spots, which are rarely encountered in flowers of other angiosperms. Little information is available on the functional traits of the green spots. In this study, we characterized the green spots in the Japanese gentian corolla using a number of microscopic techniques. Opto-digital microscopy revealed that a single visible green spot is composed of approximately 100 epidermal cells. The epidermal cells of a green spot formed a dome-like structure and the cell lumen contained many green structures that were granular and approximately 5 µm in diameter. The green structures emitted red autofluorescence when irradiated with 488 nm excitation light. Transmission electron microscopy revealed that the green structures contained typical thylakoids and grana, thus indicating they are chloroplasts. No grana were observed and the thylakoids had collapsed in the plastids of epidermal cells surrounding green spots. To estimate the rate of photosynthetic electron transfer of the green spots, we measured chlorophyll fluorescence using the MICROSCOPY version of an Imaging-PAM (pulse-amplitude-modulated) fluorometer. Under actinic light of 449 µmol m-2 s-1, substantial electron flow through photosystem II was observed. Observation of green spot formation during corolla development revealed that immature green spots formed at an early bud stage and developed to maturity associated with chloroplast degradation in the surrounding epidermal cells. These results confirmed that the Japanese gentian corolla contains functional chloroplasts in restricted areas of epidermal cells and indicated that a sophisticated program for differential regulation of chloroplast formation and degradation is operative in the epidermis.


Assuntos
Flores/citologia , Flores/metabolismo , Gentiana/anatomia & histologia , Tilacoides/metabolismo , Clorofila/metabolismo , Transporte de Elétrons , Japão , Microscopia Eletrônica de Transmissão , Microscopia de Fluorescência , Fotossíntese , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Epiderme Vegetal/citologia , Epiderme Vegetal/metabolismo , Folhas de Planta/metabolismo
14.
PLoS One ; 15(8): e0237569, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32817667

RESUMO

Several 'super-complexes' of individual hetero-oligomeric membrane protein complexes, whose function is to facilitate intra-membrane electron and proton transfer and harvesting of light energy, have been previously characterized in the mitochondrial cristae and chloroplast thylakoid membranes. We report the presence of an intra-membrane super-complex dominated by the ATP-synthase, photosystem I (PSI) reaction-center complex and the ferredoxin-NADP+ Reductase (FNR) in the thylakoid membrane. The presence of the super-complex has been documented by mass spectrometry, clear-native PAGE and Western Blot analyses. This is the first documented presence of ATP synthase in a super-complex with the PSI reaction-center located in the non-appressed stromal domain of the thylakoid membrane.


Assuntos
Cloroplastos/metabolismo , Ferredoxina-NADP Redutase/metabolismo , Óxido Nítrico Sintase/metabolismo , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , ATPases Translocadoras de Prótons/metabolismo , Tilacoides/metabolismo , Trifosfato de Adenosina/metabolismo , Transporte de Elétrons , Fotossíntese , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Spinacia oleracea/crescimento & desenvolvimento , Spinacia oleracea/metabolismo
15.
Nat Commun ; 11(1): 4079, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32796936

RESUMO

DNA methylation is an epigenetic modification that specifies the basic state of pluripotent stem cells and regulates the developmental transition from stem cells to various cell types. In flowering plants, the shoot apical meristem (SAM) contains a pluripotent stem cell population which generates the aerial part of plants including the germ cells. Under appropriate conditions, the SAM undergoes a developmental transition from a leaf-forming vegetative SAM to an inflorescence- and flower-forming reproductive SAM. While SAM characteristics are largely altered in this transition, the complete picture of DNA methylation remains elusive. Here, by analyzing whole-genome DNA methylation of isolated rice SAMs in the vegetative and reproductive stages, we show that methylation at CHH sites is kept high, particularly at transposable elements (TEs), in the vegetative SAM relative to the differentiated leaf, and increases in the reproductive SAM via the RNA-dependent DNA methylation pathway. We also show that half of the TEs that were highly methylated in gametes had already undergone CHH hypermethylation in the SAM. Our results indicate that changes in DNA methylation begin in the SAM long before germ cell differentiation to protect the genome from harmful TEs.


Assuntos
Metilação de DNA , Meristema/crescimento & desenvolvimento , Meristema/genética , Oryza/genética , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/genética , Elementos de DNA Transponíveis , Biologia do Desenvolvimento , Epigenômica , Flores , Regulação da Expressão Gênica de Plantas , Inflorescência , Folhas de Planta/metabolismo , Proteínas de Plantas/genética
16.
Ecotoxicol Environ Saf ; 204: 111056, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32763566

RESUMO

Strontium (Sr) is an emerging environmental pollutant that has become a major global concern after the nuclear accident at the Fukushima Daiichi Nuclear Power Plant in 2011. Although many studies have demonstrated the harmful effects of Sr on plant growth and development at the physiological level, knowledge regarding how plants sense and respond to Sr stress at the molecular level is limited. Recent studies have suggested that microRNAs (miRNAs) function as key regulators of plant growth and development as well as in the responses of plants to environmental stresses, including salinity, drought, cold, nutrient starvation, and heavy metals. In this study, we examined the global expression profile of miRNAs under Sr stress using small RNA sequencing analysis in Arabidopsis to better understand the molecular basis of plant responses to Sr stress. To identify specific Sr-responsive miRNAs, we performed comparative miRNA expression profiling analysis using control, CaCl2-, and SrCl2-treated seedlings. Compared to the control treatment, the expressions of most miRNAs were considerably decreased in the Sr-treated seedlings. However, under Sr stress, the expressions of primary miRNAs (pri-miRNAs) and their target genes were significantly increased; the protein levels of HYPONASTIC LEAVES 1 (HYL1), one of the core components of the microprocessor complex, were strongly reduced despite the increased HYL1 mRNA expression. In addition, hyl1-2 mutant plants were shown to be more sensitive to Sr stress than wild-type plants. Collectively, our results strongly suggested that Sr stress may be associated with the disruption of miRNA biogenesis by reducing the protein level of HYL1, which is required to maintain proper growth and development for plants. Our findings further indicated that some miRNAs may play important roles in plant responses to Sr stress.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/efeitos dos fármacos , MicroRNAs/biossíntese , Estresse Oxidativo/efeitos dos fármacos , Proteínas de Ligação a RNA/metabolismo , Poluentes do Solo/toxicidade , Estrôncio/toxicidade , Arabidopsis/genética , Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , MicroRNAs/genética , Estresse Oxidativo/genética , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Processamento Pós-Transcricional do RNA
17.
Ecotoxicol Environ Saf ; 203: 111024, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32741747

RESUMO

Pontederia cordata can tolerate heavy metal toxicity and possesses great potential for phytoremediation of heavy-metal-contaminated wetlands, yet how it copes with heavy metal stress has still not been determined. Hydroponic experiments were used to assess the effects of various levels of Cd2+ on the photosynthesis and activity of redox-regulatory systems in the plant leaves, and we also sought to elucidate the tolerance mechanism of the plant to Cd2+ by investigating Cd2+ enrichment characteristics and chemical forms. The plant can manage a low cadmium concentration (≤0.04 mM) with relatively stable biomass and photosynthetic performance. Cd2+ at the highest concentration (0.44 mM) decreased superoxide dismutase and peroxidase activities by 37.17% and 93.29%, respectively. Similar trends were demonstrated in the contents of ascorbic acid, carotenoids, lutein, glutathione, and non-protein thiol, as well as phytochelation in the leaves, exacerbating membrane peroxidation despite the significantly increased catalase activity observed. Moreover, the highest Cd2+ concentration disturbed the biosynthesis of chlorophyll precursors in the leaves, reduced chlorophyll a and b, as well as total chlorophyll contents by 60.47%, 67.47%, and 68.12%, respectively, which inhibited photosynthesis, leading to a decline in biomass. Compared with maximum quantum efficiency (Fv/Fm) and the potential activity (Fv/Fo) of photosystem II, the performance index for energy conservation from photons absorbed by PSII to the reduction of intersystem electron acceptors (PIabs), and of PSI end acceptors (PItotal), can indicate Cd2+ toxicity to the photosynthetic apparatus in the leaves. 49.95%-76.90% of the Cd2+ was sequestered in the plant roots, restraining translocation from roots to shoots, which is considered a tolerance mechanism, probably resulting from disturbed transpiration in leaves and increased Cd2+ content with low activity. Pontederia cordata is a candidate plant for phytoremediation of heavy-metal -contaminated wetlands.


Assuntos
Organismos Aquáticos/crescimento & desenvolvimento , Cádmio/toxicidade , Pontederiaceae/crescimento & desenvolvimento , Poluentes Químicos da Água/toxicidade , Áreas Alagadas , Organismos Aquáticos/metabolismo , Ácido Ascórbico/farmacologia , Biodegradação Ambiental , Biomassa , Cádmio/metabolismo , Carotenoides/metabolismo , Clorofila A/metabolismo , Fotossíntese/efeitos dos fármacos , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Pontederiaceae/metabolismo , Superóxido Dismutase/metabolismo , Poluentes Químicos da Água/metabolismo
18.
Gene ; 761: 145043, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32777530

RESUMO

Tonoplast Intrinsic Proteins (TIPs) constitute a significant class of the aquaporins. The TIPs control water trade among cytosolic and vacuolar compartments and can also transport glycerol, ammonia, urea, hydrogen peroxide, metals/metalloids, and so forth. Additionally, TIPs are engaged with different abiotic stress responses and developmental processes like leaf expansion, root elongation and seed germination. In this study, ten TIP genes in the rice genome were identified from Oryza sativa ssp indica. Among these, representative groups of TIP genes were cloned and sequenced whilst some TIP sequences showed stop codons in the coding region. The secondary structure analysis represented six conserved transmembrane helices along with the inter-helical regions having conserved motifs. The representative three-dimensional tetrameric design of protein sequence of TIP1;1 displayed key features like NPA motifs, aromatic/arginine (ar/R) selectivity filters, and Froger's residues. The vacuolar localization, transmembrane topological properties, and conserved motif analysis of the cloned genes altogether supported their identity as TIPs. An unrooted phylogenetic tree delineated the relatedness of TIPs from Oryza with different species and bunched them into five clades. The promoter analysis uncovered key regulons associated with administering abiotic stress responses. Gene expression studies showed thatTIPsare differentially regulated under salt and drought stress at various time points in shoots and roots of rice. Also, the pattern of expression was found to be significantly variable in five different rice tissues. The heat-map based tissue and stress- specific expression analysis supported the experimental findings. In conclusion, the identification and transcript-level expression studies of TIPs significantly contribute towards the comprehension of their utilitarian significance in the abiotic stress response.


Assuntos
Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Oryza/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Aquaporinas/genética , Aquaporinas/metabolismo , Clonagem Molecular/métodos , Secas , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas/genética , Genes de Plantas/genética , Oryza/metabolismo , Filogenia , Folhas de Planta/metabolismo , Cloreto de Sódio/metabolismo , Estresse Fisiológico/genética , Vacúolos/genética , Água/metabolismo
19.
J Chromatogr A ; 1626: 461370, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797849

RESUMO

Betacyanins, natural plant pigments, from Iresine herbstii Hook. ex Lindl. leaf extract were separated for the first time by high-speed countercurrent chromatography (HSCCC) in a highly polar solvent system composed of PrOH-ACN-(NH4)2SO4satd.soln-H2O (1.0:0.5:1.2:1.0; v/v/v/v) in the tail-to-head mode. The flow rate of the mobile phase was 2.0 ml/min and the column rotation speed was 860 rpm. The retention of the stationary phase was 81.0%. For the identification of separated betacyanins in the crude extract and in the HSCCC fractions, as well as for the molecular formulas and multi-step fragmentation pattern elucidation, liquid chromatography with tandem mass spectrometry and high-resolution ion-trap time-of-flight mass spectrometry were performed. The innovative application of the HSCCC system for fractionation of the betacyanins present in I. herbstii leaves enabled effective separation as well as preconcentration of the pigments for further low- and high-resolution LC-MS/MS analysis. HSCCC separation enabled identification of 22 betacyanins, of which 18 had not been detected previously in the leaves of I. herbstii, and four of these betacyanins (sinapoyl-gomphrenin and coumaroyl-gomphrenin as well as their epimers) were identified for the first time in the Iresine genus.


Assuntos
Amaranthaceae/química , Betacianinas/análise , Distribuição Contracorrente/métodos , Solventes/química , Amaranthaceae/metabolismo , Betacianinas/isolamento & purificação , Betacianinas/normas , Cromatografia Líquida de Alta Pressão/normas , Extratos Vegetais/química , Folhas de Planta/química , Folhas de Planta/metabolismo , Padrões de Referência , Espectrometria de Massas em Tandem/normas
20.
Mol Genet Genomics ; 295(6): 1393-1400, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32651630

RESUMO

Anthocyanins are a group of important secondary metabolites, functioning as colorant in plant organs as well as protective agents against several stresses. Sub-red plant (Rs) cottons, accumulating moderate level of anthocyanins in shoots, had increased photosynthesis efficiency compared to green- (GL) and red-plant (R1) cottons. The present work aimed to clarify the molecular base of anthocyanin regulation in Rs cotton. It was found that GhPAP1A was significantly up-regulated in Rs plants compared to GL cottons, but its expression level is lower than that of GhPAP1D in R1 plants. Virus induced gene silencing of GhPAP1s inhibited the red pigmentation in Rs plants. Comparative cloning revealed a 50-bp tandem repeat in the promoter of GhPAP1A in Rs cotton, which showed stronger activity to drive the expression of downstream genes in petals. Considered that the coding sequence of GhPAP1As from Rs and GL cottons had similar functions to promote anthocyanin biosynthesis in transgenic tobaccos, we attributed moderate anthocyanin accumulation in Rs cotton to increased transcription of GhPAP1A, resulted from varied promoter structure. Our works suggested GhPAP1s as useful tool to manipulate anthocyanin level and several breeding targets, including herbivore- and pathogen- resistance, high photosynthesis efficiency and colored fibers.


Assuntos
Antocianinas/biossíntese , Regulação da Expressão Gênica de Plantas , Gossypium/metabolismo , Pigmentação/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Gossypium/genética , Gossypium/crescimento & desenvolvimento , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/genética
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