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1.
Environ Sci Pollut Res Int ; 26(22): 22529-22550, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31161543

RESUMO

Widespread application of silver nanoparticles (AgNPs), due to their antibacterial and antifungal properties, increases their release into the environment and potential detrimental impact on living organisms. Plants may serve as a potential pathway for AgNPs bioaccumulation and a route into the food chain, hence investigation of AgNP phytotoxic effects are of particular importance. Since proteins are directly involved in stress response, studies of their abundance changes can help elucidate the mechanism of the AgNP-mediated phytotoxicity. In this study, we investigated proteomic changes in tobacco (Nicotiana tabacum) exposed to AgNPs and ionic silver (AgNO3). A high overlap of differently abundant proteins was found in root after exposure to both treatments, while in leaf, almost a half of the proteins exhibited different abundance level between treatments, indicating tissue-specific responses. Majority of the identified proteins were down-regulated in both tissues after exposure to either AgNPs or AgNO3; in roots, the most affected proteins were those involved in response to abiotic and biotic stimuli and oxidative stress, while in leaf, both treatments had the most prominent effect on photosynthesis-related proteins. However, since AgNPs induced higher suppression of protein abundance than AgNO3, we conclude that AgNP effects can, at least partially, be attributed to nanoparticle form.


Assuntos
Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Tabaco/fisiologia , Íons , Estresse Oxidativo/efeitos dos fármacos , Folhas de Planta/metabolismo , Proteoma/metabolismo , Proteômica , Nitrato de Prata/toxicidade , Tabaco/metabolismo
2.
BMC Plant Biol ; 19(1): 231, 2019 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-31159735

RESUMO

BACKGROUND: Four-Coumarate:CoA ligase gene (4CL) plays multiple important roles in plant growth and development by catalyzing the formation of CoA ester. 4CL belongs to the plant phenylpropane derivative, which is related to the synthesis of flavonoids and lignin and is a key enzyme in the biosynthetic pathway. RESULTS: In this study, 12 4CL genes of Fraxinus mandschurica were identified and named Fm4CL1-Fm4CL12, respectively. The analysis of the expression pattern of Fm4CL genes indicate that Fm4CL-like 1 gene may play a role in the lignin synthesis pathway. Our study indicate that overexpression of Fm4CL-like 1 increases the lignin content of transgenic tobacco by 39.5% compared to WT, and the S/G ratio of transgenic tobacco increased by 19.7% compared with WT. The xylem cell layer of transgenic line is increased by 40% compared to WT, the xylem cell wall thickness increased by 21.6% compared to the WT. Under mannitol-simulated drought stress, the root length of transgenic tobacco is 64% longer than WT, and the seed germination rate of the transgenic lines is 47% higher than that of WT. In addition, the H2O2 content in the transgenic tobacco was 22% lower than that of WT, while the POD and SOD content was higher than WT by 30 and 24% respectively, which showed Fm4CL-like 1 affect the accumulation of reactive oxygen species (ROS). The MDA content and relative conductivity was 25 and 15% lower than WT, respectively. The water loss rate is 16.7% lower than that of WT. The relative expression levels of stress-related genes NtHAK, NtAPX, NtCAT, NtABF2, and NtZFP were higher than those of WT under stress treatment. The stomatal apertures of OE (Overexpression) were 30% smaller than those of WT, and the photosynthetic rate of OE was 48% higher than that of WT. These results showed that the overexpression line exhibited stronger adaptability to osmotic stress than WT. CONCLUSIONS: Our results indicate that Fm4CL-like 1 is involved in secondary cell wall development and lignin synthesis. Fm4CL-like 1 play an important role in osmotic stress by affecting cell wall and stomatal development.


Assuntos
Secas , Proteínas de Plantas/genética , Tabaco/fisiologia , Clonagem Molecular , Fraxinus/genética , Fraxinus/metabolismo , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Estresse Fisiológico/genética , Tabaco/genética
3.
Planta ; 250(2): 589-601, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31134341

RESUMO

MAIN CONCLUSION: The absence of state transitions in a Nt(Hn) cybrid is due to a cleavage of the threonine residue from the misprocessed N-terminus of the LHCII polypeptides. The cooperation between the nucleus and chloroplast genomes is essential for plant photosynthetic fitness. The rapid and specific interactions between nucleus-encoded and chloroplast-encoded proteins are under intense investigation with potential for applications in agriculture and renewable energy technology. Here, we present a novel model for photosynthesis research in which alien henbane (Hyoscyamus niger) chloroplasts function on the nuclear background of a tobacco (Nicotiana tabacum). The result of this coupling is a cytoplasmic hybrid (cybrid) with inhibited state transitions-a mechanism responsible for balancing energy absorption between photosystems. Protein analysis showed differences in the LHCII composition of the cybrid plants. SDS-PAGE analysis revealed a novel banding pattern in the cybrids with at least one additional 'LHCII' band compared to the wild-type parental species. Proteomic work suggested that the N-terminus of at least some of the cybrid Lhcb proteins was missing. These findings provide a mechanistic explanation for the lack of state transitions-the N-terminal truncation of the Lhcb proteins in the cybrid included the threonine residue that is phosphorylated/dephosphorylated in order to trigger state transitions and therefore crucial energy balancing mechanism in plants.


Assuntos
Genoma de Cloroplastos/genética , Genoma de Planta/genética , Complexos de Proteínas Captadores de Luz/metabolismo , Tabaco/genética , Núcleo Celular/metabolismo , Cloroplastos/metabolismo , Complexos de Proteínas Captadores de Luz/genética , Fosforilação , Fotossíntese , Complexo de Proteína do Fotossistema II/genética , Complexo de Proteína do Fotossistema II/metabolismo , Proteômica , Treonina/metabolismo , Tabaco/fisiologia
4.
J Plant Res ; 132(4): 461-471, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31115709

RESUMO

Reproductive isolation, including prezygotic and postzygotic barriers, is a mechanism that separates species. Many species in the Nicotiana section Suaveolentes exhibit reproductive isolation in crosses with Nicotiana tabacum. In this study, we investigated whether the chromosome numbers and ploidy levels of eight Nicotiana suaveolens accessions are related to the reproductive isolation after crosses with N. tabacum by flow cytometry and chromosome analyses. Additionally, the internal transcribed spacer (ITS) regions of the eight N. suaveolens accessions were sequenced and compared with the previously reported sequences of 22 Suaveolentes species to elucidate the phylogenetic relationships in the section Suaveolentes. We revealed that four N. suaveolens accessions comprised 64 chromosomes, while the other four accessions carried 32 chromosomes. Depending on the ploidy levels of N. suaveolens, several types of reproductive isolation were observed after crosses with N. tabacum, including decreases in the number of capsules and the germination rates of hybrid seeds, as well as hybrid lethality and abscission of enlarged ovaries at 12-17 days after pollination. A phylogenetic analysis involving ITS sequences divided the eight N. suaveolens accessions into three distinct clades. Based on the results, we confirmed that N. suaveolens accessions vary regarding ploidy levels and reproductive isolation mechanisms in crosses with N. tabacum. These accessions will be very useful for revealing and characterizing the reproductive isolation mechanisms in interspecific crosses and their relationships with ploidy levels.


Assuntos
Ploidias , Isolamento Reprodutivo , Tabaco/genética , Cromossomos de Plantas/genética , Cruzamentos Genéticos , DNA Intergênico/genética , Citometria de Fluxo , Flores/anatomia & histologia , Germinação/genética , Filogenia , Folhas de Planta/anatomia & histologia , Análise de Sequência de DNA , Tabaco/anatomia & histologia , Tabaco/fisiologia
5.
BMC Plant Biol ; 19(1): 218, 2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31133003

RESUMO

BACKGROUND: An eukaryotic translation elongation factor-2 (eEF-2) plays an important role in protein synthesis, however, investigation on its role in abiotic stress responses is limited. A cold responsive eEF2 named as MfEF2 was isolated from yellow-flowered alfalfa [Medicago sativa subsp. falcata (L.) Arcang, thereafter M. falcata], a forage legume with great cold tolerance, and transgenic tobacco (Nicotiana tabacum L.) plants overexpressing MfEF2 were analyzed in cold tolerance and proteomic profiling was conducted under low temperature in this study. RESULTS: MfEF2 transcript was induced and peaked at 24 h and remained at the high level during cold treatment up to 96 h. Overexpression of MfEF2 in trasngenic tobacco plants resulted in enhanced cold tolerance. Compared to the wild type, transgenic plants showed higher survival rate after freezing treatment, higher levels of net photosynthetic rate (A), maximum photochemical efciency of photosystem (PS) II (Fv/Fm) and nonphotochemical quenching (NPQ) and lower levels of ion leakage and reactive oxygen species (ROS) production after chilling treatment. iTRAQ-based quantitative proteomic analysis identified 336 differentially expressed proteins (DEPs) from leaves of one transgenic line versus the wild type after chilling treatment for 48 h. GO and KEGG enrichment were conducted for analysis of the major biological process, cellular component, molecular function, and pathways of the DEPs involving in. It is interesting that many down-regulated DEPs were grouped into "photosynthesis" and "photosynthesis-antenna", such as subunits of PSI and PSII as well as light harvesting chlorophyll protein complex (LHC), while many up-regulated DEPs were grouped into "spliceosome". CONCLUSIONS: The results suggest that MfEF2 confers cold tolerance through regulating hundreds of proteins synthesis under low temperature conditions. The elevated cold tolerance in MfEF2 transgenic plants was associated with downregulation of the subunits of PSI and PSII as well as LHC, which leads to reduced capacity for capturing sunlight and ROS production for protection of plants, and upregulation of proteins involving in splicesome, which promotes alternative splicing of pre-mRNA under low temperature.


Assuntos
Adaptação Fisiológica/genética , Regulação da Expressão Gênica de Plantas , Medicago/fisiologia , Fator 2 de Elongação de Peptídeos/genética , Proteínas de Plantas/genética , Tabaco/fisiologia , Temperatura Baixa , Medicago/genética , Fator 2 de Elongação de Peptídeos/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Estresse Fisiológico/genética , Tabaco/genética
6.
BMC Plant Biol ; 19(1): 130, 2019 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-30961523

RESUMO

BACKGROUND: Potassium is a nutrient element necessary for tobacco growth. Tobacco leaves with high potassium content are elastic and tough, rich in oil. And the same time, potassium can also improve the scent and aromatic value of flue-cured tobacco by regulating the synthesis of aromatic hydrocarbons in leaves.. It is an important quality indicator for flue-cured tobacco. However, the potassium concentration in tobacco leaves in most areas of China is generally lower than the global standard for high quality tobacco. Two tobacco genotypes were grafted to each other under different potassium levels to test whether potassium content and plant growth can be improved by grafting in tobacco. RESULTS: The growth of tobacco in all treatments was inhibited under potassium starvation, and grafting significantly alleviated this potassium stress in 'Yunyan 87'. The trends in whole plant K+ uptake and K+ transfer efficiency to the leaves corresponded to the growth results of the different grafts. The nutrient depletion test results showed that the roots of 'Wufeng No.2' had higher K+ absorption potential, K+ affinity, and K+ inward flow rate. K+ enrichment circles appeared at the endoderm of the root section in the energy dispersive X-ray figure, indicating that the formation of Casparian strips may be partly responsible for the lower rate of lateral movement of K+ in the roots of 'Yunyan 87'. Gene expression analysis suggested that energy redistribution at the whole plant level might constitute one strategy for coping with potassium starvation. The feedback regulation effects between scion 'Wufeng No.2' and rootstock 'Yunyan 87' indicated that the transmission of certain signaling substances had occurred during grafting. CONCLUSIONS: 'Wufeng No.2' tobacco rootstock grafting can increase the K+ uptake and transport efficiency of 'Yunyan 87' and enhance plant growth under potassium stress. The physiological mechanism of the improved performance of grafted tobacco is related to higher K+ uptake and utilization ability, improved xylem K+ loading capacity, and up-regulated expression of genes related to energy supply systems.


Assuntos
Potássio/metabolismo , Estresse Fisiológico , Tabaco/fisiologia , Transporte Biológico , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Tabaco/genética , Tabaco/crescimento & desenvolvimento , Regulação para Cima , Xilema/genética , Xilema/crescimento & desenvolvimento , Xilema/fisiologia
7.
Phytochemistry ; 162: 99-108, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30877900

RESUMO

A single-chain variable antibody fragment (scFv) library tested against the non-structural NSP5 protein of human rotavirus A was screened by a yeast two-hybrid system against three proteins derived from the RNA-dependent RNA polymerase (RdRp) of cucumber mosaic virus (CMV), with the aim of blocking their function and preventing viral infection once expressed in planta. The constructs tested were (i) '2a' consisting of the full-length 2a gene (839 amino acids, aa), (ii) 'Motifs' covering the conserved RdRp motifs (IV-VII) (132 aa) and (iii) 'GDD' located within the conserved RdRp motif VI (GDD, 22 aa). In yeast two-hybrid (Y2H) selection assays the '2a' and 'Motifs' constructs interacted with 96 and 25 library constructs, respectively, while the 'GDD' construct caused transactivation. Y2H-interacting scFvs were analyzed in vivo for their interaction with the 2a and Motifs proteins in a mammalian transient expression system. Eighteen tobacco lines stably transformed with four selected scFvs were produced and screened for resistance against two different CMV isolates. Different levels of resistance and rate of recovery were observed with CMV of both groups I and II, particularly in lines expressing intrabodies against the full-length 2a protein. This work describes for the first time the use of intrabodies against the RdRp of CMV to obtain plants that reduce infection of a pandemic virus, showing that the selected scFvs can modulate virus infection and induce premature recovery in tobacco plants.


Assuntos
Especificidade de Anticorpos , Cucumovirus/fisiologia , Engenharia Genética/métodos , RNA Replicase/imunologia , Anticorpos de Cadeia Única/imunologia , Tabaco/genética , Tabaco/fisiologia , Sequência de Aminoácidos , Animais , Linhagem Celular , Cucumovirus/enzimologia , Plantas Geneticamente Modificadas , Anticorpos de Cadeia Única/química , Transformação Genética
8.
BMC Plant Biol ; 19(1): 118, 2019 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-30922239

RESUMO

BACKGROUND: The transmitting tissue of the style is the pathway for pollen tube growth to the ovules and has components that function in recognizing and discriminating appropriate pollen genotypes. In Nicotiana tabacum, the class III pistil extensin-like (PELPIII) arabinogalactan protein is essential for the inhibition of N. obtusifolia pollen tube growth. The transmitting tissue-specific (TTS) arabinogalactan protein amino acid sequence and expression pattern is similar to PELPIII, but it facilitates self-pollinated N. tabacum. The TTS and PELPIII arabinogalactan protein can be divided into the less conserved N-terminal (NTD) and the more conserved C-terminal (CTD) domains. This research tested whether the NTD is the key domain in determining PELPIII function in the inhibition of interspecific pollen tube growth. Three variant PELPIII gene constructs were produced where the PELPIII NTD was exchanged with the TTS NTD and a single amino acid change (cysteine to alanine) was introduced into the PELPIII NTD. The PELPIII variants of N. tabacum were tested for activity by measuring the inhibition N. obtusifolia pollen tube growth by using them to complement a 3'UTR RNAi transgenic line with reduced PELPIII mRNA. RESULTS: The RNAi N. tabacum line had reduced PELPIII mRNA accumulation and reduced inhibition of N. obtusifolia pollen tube growth, but had no effect on self-pollen tube growth or pollen tube growth of 12 other Nicotiana species. The NTD of PELPIII with either the PELPIII or TTS CTDs complemented the loss PELPIII activity in the RNAi transgenic line as measured by inhibition of N. obtusifolia pollen tube growth. The TTS NTD with the PELPIII CTD and a variant PELPIII with a cysteine to alanine mutation in its NTD failed to complement the loss of PELPIII activity and did not inhibit N. obtusifolia pollen tube growth. CONCLUSION: The NTD is a key determinant in PELPIII's function in regulating interspecific pollen tube growth and is a first step toward understanding the mechanism of how PELPIII NTD regulates pollen tube growth.


Assuntos
Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Tubo Polínico/crescimento & desenvolvimento , Reprodução/fisiologia , Tabaco/fisiologia , Regiões 3' não Traduzidas , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/efeitos dos fármacos , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Tubo Polínico/genética , Domínios Proteicos , Interferência de RNA
9.
Int J Mol Sci ; 20(5)2019 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-30857203

RESUMO

APETALA2/ethylene-responsive factor superfamily (AP2/ERF) is a transcription factor involved in abiotic stresses, for instance, cold, drought, and low oxygen. In this study, a novel ethylene-responsive transcription factor named AdRAP2.3 was isolated from Actinidia deliciosa 'Jinkui'. AdRAP2.3 transcription levels in other reproductive organs except for the pistil were higher than those in the vegetative organs (root, stem, and leaf) in kiwi fruit. Plant hormones (Salicylic acid (SA), Methyl-jasmonate acid (MeJA), 1-Aminocyclopropanecarboxylic Acid (ACC), Abscisic acid (ABA)), abiotic stresses (waterlogging, heat, 4 °C and NaCl) and biotic stress (Pseudomonas Syringae pv. Actinidiae, Psa) could induce the expression of AdRAP2.3 gene in kiwi fruit. Overexpression of the AdRAP2.3 gene conferred waterlogging stress tolerance in transgenic tobacco plants. When completely submerged, the survival rate, fresh weight, and dry weight of transgenic tobacco lines were significantly higher than those of wile type (WT). Upon the roots being submerged, transgenic tobacco lines grew aerial roots earlier. Overexpression of AdRAP2.3 in transgenic tobacco improved the pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) enzyme activities, and improved the expression levels of waterlogging mark genes NtPDC, NtADH, NtHB1, NtHB2, NtPCO1, and NtPCO2 in roots under waterlogging treatment. Overall, these results demonstrated that AdRAP2.3 might play an important role in resistance to waterlogging through regulation of PDC and ADH genes in kiwi fruit.


Assuntos
Actinidia/fisiologia , Etilenos/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/fisiologia , Estresse Fisiológico , Tabaco/fisiologia , Fatores de Transcrição/metabolismo , Actinidia/genética , Álcool Desidrogenase/genética , Álcool Desidrogenase/metabolismo , Genes de Plantas , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Piruvato Descarboxilase/genética , Piruvato Descarboxilase/metabolismo , Tabaco/genética , Fatores de Transcrição/genética
10.
Plant Sci ; 280: 416-423, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30824021

RESUMO

Cadmium (Cd) toxicity induces oxidative burst and leads to programmed cell death (PCD) in plant cells. The role of salicylic acid-induced protein kinase (SIPK) signaling pathway in Cd-induced oxidative stress was investigated in suspension-cultured tobacco (Nicotiana tabacum L. cv. Barley 21). The cells were pretreated with 40 µM PD98059 (inhibitor of MAPKK) and then exposed to 50 µM Cd for 24 h. The percentages of cell viability, apoptosis, necrosis, and the content of reactive oxygen species (ROS) were monitored by flow cytometry. Expression of PCD related gene (Hsr203J) and the contents of certain signaling molecules were measured as well. The results showed that Cd increased the expression of SIPK, Hsr203J, and CAT genes, the activities of catalase and caspase-3-like enzymes. Addition of PD98059 inhibitor reduced the expression of Hsr203J and CAT genes, decreased CAT activity, but increased ROS and SA contents, and caspase-3-like activity and apoptosis rate. The highest apoptosis level was accompanied by the highest level of Hsr203J gene expression. From the results it can be suggested that upon treatment of tobacco cells with Cd, internal SA content increased and induced the SIPK signaling pathway, thereby inhibited the antioxidant system and led to PCD.


Assuntos
Antioxidantes/metabolismo , Cádmio/toxicidade , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Tabaco/fisiologia , Apoptose , Catalase/genética , Catalase/metabolismo , Esterases/efeitos dos fármacos , Esterases/genética , Flavonoides/farmacologia , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases Ativadas por Mitógeno/genética , Estresse Oxidativo , Proteínas de Plantas/efeitos dos fármacos , Proteínas de Plantas/genética , Inibidores de Proteínas Quinases/farmacologia , Ácido Salicílico/metabolismo , Tabaco/efeitos dos fármacos , Tabaco/genética
11.
Int J Biol Macromol ; 130: 50-57, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30797010

RESUMO

Expansins play a pivotal role in plant adaptation to environmental stress via cell wall loosening. To evaluate the roles of expansin in response to different environmental stress conditions, the expansin gene PttEXPA8 from Populus tomentosa was transformed into tobacco. Analysis of physiological indices demonstrated the transgenic plants with improved resistance to heat, drought, salt, cold, and cadmium stress but to different extents. In mature plants, PttEXPA8 exerted the greatest effect on heat stress, with a response index value of 137.46%, followed by drought, cadmium, cold, and salt stress with response index values of 101.04%, 70.61%, 69.95%, and 54.68%, respectively. Over-expression of PttEXPA8 resulted in differential responses in physiological indices to the stresses. Soluble sugar content showed the highest response to the stresses, with an average response index value of 29.29%, whereas the absolute response index value for malondialdehyde content, relative electrolyte leakage, chlorophyll content, and superoxide dismutase activity ranged from 11.01% to 19.21%. The present results provide insight into the roles of expansin in stress resistance in Populus.


Assuntos
Proteínas de Plantas/genética , Populus/genética , Estresse Fisiológico , Tabaco/genética , Tabaco/fisiologia , Plantas Geneticamente Modificadas , Plântula/crescimento & desenvolvimento , Tabaco/crescimento & desenvolvimento
12.
Plant Physiol Biochem ; 137: 14-24, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30710795

RESUMO

Glutamyl-tRNA reductase1 (HEMA1) and ferrochelatase1 (FC1) are both expressed in response to salt stress in the biosynthetic pathway of tetrapyrroles. Peanut (Arachis hypogaea L.) HEMA1 and FC1 were isolated by RT-PCR. The amino acid sequence encoded by the two genes showed high similarity with that in other plant species. The AhFC1 fusion protein was verified to function in chloroplast using Arabidopsis mesophyll protoplast. Sense and wild-type (WT) tobaccos were used to further study the physiological effects of AhHEMA1 and AhFC1. Compared with WT, the Heme contents and germination rate were higher in AhFC1 overexpressing plants under salt stress. Meanwhile, overexpressing AhHEMA1 also led to higher ALA and chlorophyll contents and multiple physiological changes under salt stress, such as higher activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX), lower contents of reactive oxygen species (ROS) and slighter membrane damage. In addition, the activities of CAT, POD and APX in the AhFC1 overexpressing plants were significantly higher than that in WT lines under salt stress, but the activity of SOD between the WT plants and the transgenic plants did not exhibit significant differences. These results suggested that, peanut can enhance resistance to salt stress by improving the biosynthesis of tetrapyrrole biosynthetic.


Assuntos
Arachis/genética , Proteínas de Plantas/genética , Estresse Salino/genética , Tabaco/genética , Ácido Aminolevulínico/metabolismo , Membrana Celular/metabolismo , Clorofila/genética , Clorofila/metabolismo , Cloroplastos/genética , Cloroplastos/metabolismo , Enzimas/genética , Enzimas/metabolismo , Regulação da Expressão Gênica de Plantas , Germinação/genética , Heme/biossíntese , Heme/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Espécies Reativas de Oxigênio/metabolismo , Estresse Salino/fisiologia , Plântula/genética , Plântula/metabolismo , Tetrapirróis/genética , Tetrapirróis/metabolismo , Tabaco/fisiologia
13.
Photochem Photobiol Sci ; 18(2): 359-366, 2019 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-30534744

RESUMO

ß-Aminobutyric acid (BABA) pre-treatment has been shown to alter both biotic and abiotic stress responses. The present study extends this observation to acclimative UV-B-response, which has not been explored in this context so far. A single soil application of 300 ppm BABA modified the non-enzymatic antioxidant capacities and the leaf hydrogen peroxide levels in tobacco (Nicotiana tabacum L.) leaves in response to a 9-day treatment with 5.4 kJ m-2 d-1 biologically effective supplementary UV-B radiation in a model experiment that was performed in a growth chamber. BABA decreased leaf hydrogen peroxide levels both as a single factor and in combination with UV-B, but neither BABA nor UV-B affected leaf photochemistry significantly. The total antioxidant capacities were increased by either BABA or UV-B, and this response was additive in BABA pre-treated leaves. These results together with the observed changes in hydroxyl radical neutralising ability and non-enzymatic hydrogen peroxide antioxidant capacities show that BABA pre-treatment (i) has a long-term effect on leaf antioxidants even in the absence of other factors and (ii) modifies acclimative readjustment of prooxidant-antioxidant balance in response to UV-B. BABA-inducible antioxidants do not include phenolic compounds as a UV-B-induced increase in the adaxial leaf flavonoid index and total leaf extract UV absorption were unaffected by BABA.


Assuntos
Aclimatação/efeitos da radiação , Aminobutiratos/farmacologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/efeitos da radiação , Tabaco/efeitos dos fármacos , Tabaco/efeitos da radiação , Raios Ultravioleta , Aclimatação/efeitos dos fármacos , Relação Dose-Resposta a Droga , Folhas de Planta/fisiologia , Tabaco/fisiologia
14.
J Integr Plant Biol ; 61(5): 598-610, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30589207

RESUMO

Programmed cell death (PCD) is an essential process for development, and shows conserved cytological features in both plants and animals. Caspases are well-known critical components of the PCD machinery in animals. However, currently few typical counterparts have been identified in plants and only several caspase-like proteases are known to be involved in plant PCD, indicating the existence of great challenge for confirming new caspase-like proteases and elucidating the mechanisms regulating plant PCD. Here, we report a novel cysteine protease, NtTPE8, which was extracted from tobacco seeds and confirmed as a new caspase-like protease. Recombinant NtTPE8 exhibited legumain and caspase-like proteolytic activities, both of which could be inhibited by the pan-caspase inhibitor (Z-VAD-FMK). Notably, NtTPE8 possessed several caspase activities and the capacity to cleave the cathepsin H substrate FVR, indicating a unique character of NtTPE8. NtTPE8 was exclusively expressed in the integumentary tapetum and thus, is the first specific molecular marker reported to date for this cell type. Down-regulation of NtTPE8 caused seed abortion, via disturbing early embryogenesis, indicating its critical role in embryogenesis and seed development. In conclusion, we identified a novel caspase-like cysteine protease, NtTPE8, exclusively expressed in the integumentary tapetum that is involved in seed development.


Assuntos
Proteínas de Plantas/metabolismo , Sementes/metabolismo , Tabaco/metabolismo , Caspases/genética , Caspases/metabolismo , Proteínas de Plantas/genética , Sementes/crescimento & desenvolvimento , Sementes/fisiologia , Tabaco/crescimento & desenvolvimento , Tabaco/fisiologia
15.
Gene ; 682: 67-80, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30292869

RESUMO

Evolutionarily conserved microRNAs such as miR156, miR159, miR167 and miR172 tightly regulate the extensive array of gene expression during flowering in plants, through instant and long-term alterations in the expression of their target genes. Here we employed a novel target-mimicry approach for the diminution of auxin signalling regulator miRNA167 by developing mimic-transgenic lines in tobacco, to investigate the transcriptional biases of flowering-associated miRNAs in apical and floral meristematic tissues and their phenotypic implications. Recorded morpho-alterations such as uneven flowering-time phenotypes, anomalous floral organ formation, and large variations in the seed forming characteristics permitted us to determine the consequence of the extent of miR167 expression diminution accompanying the transcriptional biases of interrelated miRNAs. We demonstrate that percent diminution of miR167 gene expression is proportionally associated with both early and late flowering-time phenotypes in mimic lines. Also, the associated miRNAs, miR156, miR159, and miR172 showed >90% transcriptional diminution in at least 'early-flowering' miR167 mimic lines. On contrary, low percentages of their respective diminution were recorded in 'late-flowering' lines. Evidently, the misexpression of miR156, miR159, and miR172 led to the over-expression of their respective target genes SPL9, AtMYB33-like and AP2 genes in mimic lines which resulted in assorted phenotypes. We describe the scope of spatial regulation of these microRNAs in floral bud tissues of mimic lines which showed negative- or very low (<25%) misexpression levels in early/late-flowering lines highlighting their roles in the acquisition of flowering mechanism. To our knowledge, this study represents the first characterization of transcriptional biases of flowering associated miRNAs in miR167-mimic lines and certainly augments our understanding of the importance of microRNA-mediated regulation of flowering in plants.


Assuntos
Flores/fisiologia , Regulação da Expressão Gênica de Plantas , MicroRNAs/genética , Tabaco/genética , Flores/genética , Perfilação da Expressão Gênica , Inativação Gênica , Meristema/genética , Meristema/fisiologia , Fenótipo , Pólen/genética , RNA de Plantas/genética , Sementes/genética , Tabaco/fisiologia , Transcrição Genética , Transgenes
16.
BMC Plant Biol ; 18(1): 355, 2018 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-30547756

RESUMO

BACKGROUND: Plant phospholipase D (PLD), which can hydrolyze membrane phospholipids to produce phosphatidic acid (PA), a secondary signaling molecule, has been proposed to function in diverse plant stress responses. Both PLD and PA play key roles in plant growth, development, and cellular processes. PLD was suggested to mediate the regulation of stomatal movements by abscisic acid (ABA) as a response to water deficit. In this research, we characterized the roles of the cucumber phospholipase D alpha gene (CsPLDα, GenBank accession number EF363796) in the growth and tolerance of transgenic tobacco (Nicotiana tabacum) to drought stress. RESULTS: The CsPLDα overexpression in tobacco lines correlated with the ABA synthesis and metabolism, regulated the rapid stomatal closure in drought stress, and reduced the water loss. The NtNCED1 expression levels in the transgenic lines and wild type (WT) were sharply up-regulated after 16 days of drought stress compared with those before treatment, and the expression level in the transgenic lines was significantly higher than that in the WT. The NtAOG expression level evidently improved after 8 and 16 days compared with that at 0 day of treatment and was significantly lower in the transgenic lines than in the WT. The ABA content in the transgenic lines was significantly higher than that in the WT. The CsPLDα overexpression could increase the osmolyte content and reduce the ion leakage. The proline, soluble sugar, and soluble protein contents significantly increased. By contrast, the electrolytic leakage and malondialdehyde accumulation in leaves significantly decreased. The shoot and root fresh and dry weights of the overexpression lines significantly increased. These results indicated that a significant correlation between CsPLDα overexpression and improved resistance to water deficit. CONCLUSIONS: The plants with overexpressed CsPLDα exhibited lower water loss, higher leaf relative water content, and heavier fresh and dry matter accumulation than the WT. We proposed that CsPLDα was involved in the ABA-dependent pathway in mediating the stomatal closure and preventing the elevation of intracellular solute potential.


Assuntos
Cucumis sativus/genética , Ácidos Fosfatídicos/genética , Fosfolipase D/genética , Estresse Fisiológico/genética , Tabaco/fisiologia , Ácido Abscísico/metabolismo , Secas , Regulação da Expressão Gênica de Plantas , Peroxidação de Lipídeos/genética , Peroxidação de Lipídeos/fisiologia , Malondialdeído/metabolismo , Ácidos Fosfatídicos/metabolismo , Fosfolipase D/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Estômatos de Plantas/fisiologia , Plantas Geneticamente Modificadas , Prolina/metabolismo , Tabaco/genética , Água/metabolismo
17.
Plant Physiol Biochem ; 132: 515-523, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30312954

RESUMO

In this study, a cDNA of ICE1 (inducer of CBF expression 1) gene, named BcICE1, was isolated from Brassica campestris 'Longyou 6'. The deduced protein has 499 amino acids containing a typical bHLH domain and is highly identical with AtICE1 (85.9%) from Arabidopsis thaliana. BcICE1 is located in the nucleus. The activities of SOD, CAT, POD, and APX and the transcriptional levels of SOD, CAT, and POD genes were higher in BcICE1-transgenic tobacco than in wild-type (WT) tobacco under cold stress. Compared with WT tobacco, proline, soluble sugar, and chlorophyll were enhanced, whereas malondialdehyde and relative conductivity were decreased in BcICE1-transgenic tobacco. The overexpression of BcICE1 in tobacco increased the expression of CBF1, CBF2, and other stress-related genes. Moreover, under salt and PEG (25%) stress, the activities of APX and GPX and content of soluble sugar and chlorophyll in BcICE1-transgenic tobacco were higher than those in WT tobacco. Our results suggest that BcICE1 plays an important role in the response to abiotic stress.


Assuntos
Adaptação Fisiológica/genética , Brassica/genética , Genes de Plantas , Proteínas de Plantas/genética , Estresse Fisiológico/genética , Tabaco/genética , Tabaco/fisiologia , Sequência de Aminoácidos , Antioxidantes/metabolismo , Núcleo Celular/metabolismo , Clorofila/metabolismo , Clonagem Molecular , Regulação da Expressão Gênica de Plantas , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Prolina/metabolismo , Frações Subcelulares/metabolismo , Tabaco/enzimologia
18.
BMC Plant Biol ; 18(1): 183, 2018 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-30189843

RESUMO

BACKGROUND: Pollen development is a strictly controlled post-meiotic process during which microspores differentiate into microgametophytes and profound structural and functional changes occur in organelles. Annexin 5 is a calcium- and lipid-binding protein that is highly expressed in pollen grains and regulates pollen development and physiology. To gain further insights into the role of ANN5 in Arabidopsis development, we performed detailed phenotypic characterization of Arabidopsis plants with modified ANN5 levels. In addition, interaction partners and subcellular localization of ANN5 were analyzed to investigate potential functions of ANN5 at cellular level. RESULTS: Here, we report that RNAi-mediated suppression of ANN5 results in formation of smaller pollen grains, enhanced pollen lethality, and delayed pollen tube growth. ANN5 RNAi knockdown plants also displayed aberrant development during the transition from the vegetative to generative phase and during embryogenesis, reflected by delayed bolting time and reduced embryo size, respectively. At the subcellular level, ANN5 was delivered to the nucleus, nucleolus, and cytoplasm, and was frequently localized in plastid nucleoids, suggesting a likely role in interorganellar communication. Furthermore, ANN5-YFP co-immunoprecipitated with RABE1b, a putative GTPase, and interaction in planta was confirmed in plastidial nucleoids using FLIM-FRET analysis. CONCLUSIONS: Our findings let us to propose that ANN5 influences basal cell homeostasis via modulation of plastid activity during pollen maturation. We hypothesize that the role of ANN5 is to orchestrate the plastidial and nuclear genome activities via protein-protein interactions however not only in maturing pollen but also during the transition from the vegetative to the generative growth and seed development.


Assuntos
Anexina A5/fisiologia , Proteínas de Arabidopsis/fisiologia , Arabidopsis/crescimento & desenvolvimento , Núcleo Celular/metabolismo , Proteínas de Cloroplastos/farmacologia , Plastídeos/fisiologia , Pólen/crescimento & desenvolvimento , Proteínas rab1 de Ligação ao GTP/farmacologia , Anexina A5/genética , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/farmacologia , Clorofila/metabolismo , Proteínas de Cloroplastos/genética , Técnicas de Silenciamento de Genes , Genes de Plantas , Homeostase , Pólen/anatomia & histologia , Pólen/genética , Tubo Polínico/crescimento & desenvolvimento , Plântula/metabolismo , Tabaco/genética , Tabaco/fisiologia , Transcriptoma , Proteínas rab1 de Ligação ao GTP/genética
19.
Plant Sci ; 274: 201-211, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30080605

RESUMO

Lateral root branching along the primary root involves complex gene regulatory networks in model plant Arabidopsis. However, it is largely unclarified whether different plant species share a common mechanism to pattern the lateral root along the primary axis. In this study, we assessed the development pattern of lateral root among several dicot and monocot plants, including Arabidopsis, tomato, Medicago, Nicotiana, rice, and ryegrass by using an agar-gel culture system. Our results reveal a regular-spaced distribution pattern of lateral roots along the primary root axis of both dicot and monocot plants. Meanwhile, the root patterning is tightly controlled by root bending and the plant hormone auxin. However, nitrogen and phosphate starvations trigger distinguished root growth patterns among different plant species. Our studies strongly suggest a partially shared signaling pathway underlying root patterning of various plant species, and also provide a foundation for further identification of genes associated with root development.


Assuntos
Desenvolvimento Vegetal , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Plantas , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/fisiologia , Ácidos Indolacéticos/metabolismo , Lolium/crescimento & desenvolvimento , Lolium/fisiologia , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/fisiologia , Medicago/crescimento & desenvolvimento , Medicago/fisiologia , Oryza/crescimento & desenvolvimento , Oryza/fisiologia , Fenômenos Fisiológicos Vegetais , Raízes de Plantas/fisiologia , Transdução de Sinais , Tabaco/crescimento & desenvolvimento , Tabaco/fisiologia
20.
Plant Cell Physiol ; 59(11): 2381-2393, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30124925

RESUMO

Light signaling and phytohormones play important roles in plant growth, development, and biotic and abiotic stress responses. However, the roles of phytochromes and cross-talk between these two signaling pathways in response to salt stress in tobacco plants remain underexplored. Here, we explored the defense response in phytochrome-defective mutants under salt stress. We monitored the physiological and molecular changes of these mutants under salt stress conditions. The results showed that phytochrome A (phyA), phytochrome B (phyB) and phyAphyB (phyAB) mutants exhibited improved salt stress tolerance compared with wild-type (WT) plants. The mutant plants had a lower electrolyte leakage (EL) and malondialdehyde (MDA) concentration than WT plants, and the effect was clearly synergistic in the phyAB double mutant plants. Furthermore, the data showed that the transcript levels of defense-associated genes and the activities of some antioxidant enzymes in the mutant plants were much higher than those in WT plants. Additionally, the results indicated that phytochrome signaling strongly modulates the expression of endogenous abscisic acid (ABA) and jasmonic acid (JA) of Nicotiana tobacum in response to salt stress. To illustrate further the relationship between phytochrome and phytohormone, we measured the expression of defense genes and phytochrome. The results displayed that salt stress and application of methyl jasmonate (MeJA) or ABA up-regulated the transcript levels of salt response-associated genes and inhibited the expression of NtphyA and NtphyB. Foliar application of inhibitors of ABA and JA further confirmed that JA co-operated with ABA in phytochrome-mediated salt stress tolerance.


Assuntos
Ácido Abscísico/metabolismo , Ciclopentanos/metabolismo , Oxilipinas/metabolismo , Fitocromo A/fisiologia , Fitocromo B/fisiologia , Reguladores de Crescimento de Planta/metabolismo , Tolerância ao Sal/fisiologia , Tabaco/metabolismo , Regulação da Expressão Gênica de Plantas , Fotossíntese , Fitocromo A/metabolismo , Fitocromo B/metabolismo , Plantas Tolerantes a Sal/metabolismo , Plantas Tolerantes a Sal/fisiologia , Tabaco/fisiologia
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