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1.
Ying Yong Sheng Tai Xue Bao ; 30(7): 2338-2344, 2019 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-31418237

RESUMO

To obtain salt-alkali tolerant strains which could be potenially used to improve the quality of saline-alkali soil, soil samples collected from Dongying, Shandong Province were diluted and spread to modified Gibbson medium with pH 9 and salt concentration of 100 g·L-1. A total of 18 bacteria strains were obtained. By increasing salt concentration and pH, an extremely salt-alkali tole-rant strain N14 was screened which could grow at pH 12 and salt concentration of 20%. We analyzed the morphological, physiological and biochemical characters and 16S rDNA sequence of N14. The strain N14 was identified as Bacillus marmarensis. N14 bacterial fertilizer significantly increased the biomass of wheat, improved shoot height, fresh weight and dry weight by 21.8%, 57.9% and 41.7%, respectively. The addition of N14 bacterial fertilizer significantly increased the chlorophyll a, chlorophyll b and total chlorophyll in wheat by 36.4%, 20.0% and 31.7%, respectively. It significantly increased the activities of invertase, urease and alkaline phosphatase in saline-alkali soil by 23.2%, 68.8% and 106.5%, respectively. It also significantly increased the activities of superoxide dismutase, peroxidase and catalase in roots by 109.6%, 17.8% and 50%, respectively. The concentration of malondialdehyde in wheat roots was significantly reduced by 39.8%. This study provided an idea for the application of extreme salt-alkali tolerant bacteria and a way for improvement of saline-alkali soil.


Assuntos
Fertilizantes , Plantas Tolerantes a Sal/fisiologia , Triticum/fisiologia , Agricultura , Álcalis , Clorofila A , Solo , Microbiologia do Solo
2.
Sci Total Environ ; 685: 827-835, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31242461

RESUMO

Recretohalophytes employ specialized glands to excrete salt ions onto their tissue surfaces, which then have the potential to be transported away from the plant via wind in a process referred to as 'haloconduction'. Spartina pectinata and Distichlis spicata were selected to investigate the potential to remediate a cement kiln dust landfill in Bath, ON via salt excretion and haloconduction. Under ideal conditions in the laboratory, measurements of salt excreted by large (>15 shoots and > 50 cm height) plants of each species were 280 ±â€¯164 g/m2 and 164 ±â€¯75 g/m2, respectively, resulting in potential remediation timeframes of 1.4 ±â€¯0.9 and 2.4 ±â€¯1.1 years. Three salt collection methods were developed and installed in the field to test their efficacy for capturing and measuring windborne salt mobilized from plant surfaces. All three methods (two ground-level and one at 260 cm height) were successful in capturing and quantifying airborne salts up to 15 m from the plots. This study is the first to collect and quantify dispersed salt from recretohalophytes and hence confirm the theory of haloconduction, a promising new remediation technology for salt-impacted soils.


Assuntos
Biodegradação Ambiental , Poaceae/fisiologia , Plantas Tolerantes a Sal/fisiologia , Poeira , Plantas , Cloreto de Sódio , Solo , Poluentes do Solo , Instalações de Eliminação de Resíduos
3.
Plant Sci ; 285: 14-25, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203878

RESUMO

Intracellular Na+/H+ antiporters (NHXs) play important roles in plant tolerance to salt stress. However, plant NHXs functioning in salt tolerance and the underlying physiological mechanisms remain poorly understood. In this report, we report the identification and functional characterization of PbrNHX2 isolated from Pyrus betulaefolia. PbrNHX2 expression levels were induced by salt, and dehydration, but was unaffected by cold. PbrNHX2 was localized in the tonoplast. Overexpression of PbrNHX2 in tobacco and Pyrus ussuriensis conferred enhanced tolerance to salt tolerance, whereas down-regulation of PbrNHX2 in Pyrus betulaefolia by virus-induced gene silencing (VIGS) resulted in elevated salt sensitivity. The transgenic lines contained lower levels of Na+, higher levels of K+, and higher K/Na ratio, whereas they were changed in an opposite way when PbrNHX2 was silenced. In addition, the transgenic plants accumulated lower levels of reactive oxygen species compared with wild type, accompanied by higher activities of three antioxidant enzymes. Taken together, the data demonstrate that PbrNHX2 plays a positive role in salt tolerance and that it holds a great potential for engineering salt tolerance in crops.


Assuntos
Genes de Plantas/fisiologia , Proteínas de Plantas/metabolismo , Pyrus/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Plantas Tolerantes a Sal/metabolismo , Trocadores de Sódio-Hidrogênio/metabolismo , Inativação Gênica , Proteínas de Plantas/genética , Proteínas de Plantas/fisiologia , Plantas Geneticamente Modificadas , Pyrus/genética , Pyrus/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Estresse Salino , Plantas Tolerantes a Sal/genética , Plantas Tolerantes a Sal/fisiologia , Trocadores de Sódio-Hidrogênio/genética , Trocadores de Sódio-Hidrogênio/fisiologia , Tabaco
4.
Plant Sci ; 285: 248-257, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203890

RESUMO

Halophytic Oryza coarctata is a good model system to examine mechanisms of salinity tolerance in rice. O. coarctata leaves show the presence of microhairs in adaxial leaf surface furrows that secrete salt under salinity. However, detailed molecular and physiological studies of O. coarctata microhairs are limited due to their relative inaccessibility. This work presents a detailed characterization of O. coarctata leaf features. O. coarctata has two types of microhairs on the adaxial leaf surface: longer microhairs (three morphotypes) lining epidermal furrow walls and shorter microhairs (reported first time) arising from bulliform cells. Microhair morphotypes include (i) finger-like, tubular structures, (ii) tubular hairs with bilobed and flattened heads and (iii) bi-or trifurcated hairs. The unicellular nature of microhairs was confirmed by propidium iodide (PI) staining. An efficient method for the isolation and enrichment of O. coarctata microhairs is presented (yield averaging ˜2 × 105/g leaf tissue). The robustness of the microhair isolation procedure was confirmed by subsequent viability staining (PI), total RNA isolation and RT-PCR amplification of O. coarctata trichome-specific WUSCHEL-related homeobox 3B (OcWox3B) and transporter gene-specific cDNA sequences. The present microhair isolation work from O. coarctata paves the way for examining genes involved in ion secretion in this halophytic wild rice model.


Assuntos
Oryza/anatomia & histologia , Folhas de Planta/anatomia & histologia , Plantas Tolerantes a Sal/anatomia & histologia , Microscopia Confocal , Oryza/fisiologia , Folhas de Planta/citologia , Folhas de Planta/fisiologia , Folhas de Planta/ultraestrutura , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Plantas Tolerantes a Sal/fisiologia , Tricomas/anatomia & histologia , Tricomas/fisiologia , Tricomas/ultraestrutura
5.
BMC Plant Biol ; 19(1): 213, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31117942

RESUMO

BACKGROUND: Atriplex canescens is a typical C4 secretohalophyte with salt bladders on the leaves. Accumulating excessive Na+ in tissues and salt bladders, maintaining intracellular K+ homeostasis and increasing leaf organic solutes are crucial for A. canescens survival in harsh saline environments, and enhanced photosynthetic activity and water balance promote its adaptation to salt. However, the molecular basis for these physiological mechanisms is poorly understood. Four-week-old A. canescens seedlings were treated with 100 mM NaCl for 6 and 24 h, and differentially expressed genes in leaves and roots were identified, respectively, with Illumina sequencing. RESULTS: In A. canescens treated with 100 mM NaCl, the transcripts of genes encoding transporters/channels for important nutrient elements, which affect growth under salinity, significantly increased, and genes involved in exclusion, uptake and vacuolar compartmentalization of Na+ in leaves might play vital roles in Na+ accumulation in salt bladders. Moreover, NaCl treatment upregulated the transcripts of key genes related to leaf organic osmolytes synthesis, which are conducive to osmotic adjustment. Correspondingly, aquaporin-encoding genes in leaves showed increased transcripts under NaCl treatment, which might facilitate water balance maintenance of A. canescens seedlings in a low water potential condition. Additionally, the transcripts of many genes involved in photosynthetic electron transport and the C4 pathway was rapidly induced, while other genes related to chlorophyll biosynthesis, electron transport and C3 carbon fixation were later upregulated by 100 mM NaCl. CONCLUSIONS: We identified many important candidate genes involved in the primary physiological mechanisms of A. canescens salt tolerance. This study provides excellent gene resources for genetic improvement of salt tolerance of important crops and forages.


Assuntos
Atriplex/fisiologia , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Tolerância ao Sal/genética , Plantas Tolerantes a Sal/fisiologia , Transcriptoma , Atriplex/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas/fisiologia , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Plantas Tolerantes a Sal/genética , Transcriptoma/efeitos dos fármacos
6.
J Plant Physiol ; 236: 23-33, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30851648

RESUMO

Faba bean (Vicia faba L.) is sensitive to salinity. While toxic effects of sodium (Na+) are well studied, toxicity aspects of chloride (Cl-) and the underlying tolerance mechanisms to Cl- are not well understood. For this reason, shoot Cl- translocation and its effect as potential determinant for tolerance was tested. Diverse V. faba varieties were grown hydroponically and stressed with 100 mM NaCl until necrotic leaf spots appeared. At this point, biomass formation, oxidative damage of membranes as well as Na+, Cl- and potassium concentrations were measured. The V. faba varieties contrasted in the length of the period they could withstand the NaCl stress treatment. More tolerant varieties survived longer without evolving necrosis and were less affected by inhibitory effects on photosynthesis. The concentration of Cl- at the time point of developing leaf necrosis was in the same range irrespective of the variety, while that of Na+ varied. This indicates that Cl- concentrations, and not Na+ concentrations are critical for the formation of salt necrosis in faba bean. Tolerant varieties profited from lower Cl- translocation to leaves. Therefore, photosynthesis was less affected in those varieties with lower Cl-. This mechanism is a new trait of interest for salt tolerance in V. faba.


Assuntos
Cloretos/metabolismo , Brotos de Planta/metabolismo , Vicia faba/metabolismo , Transporte Biológico , Oxirredução , Fotossíntese , Brotos de Planta/fisiologia , Transpiração Vegetal , Potássio/metabolismo , Tolerância ao Sal , Plantas Tolerantes a Sal/metabolismo , Plantas Tolerantes a Sal/fisiologia , Sódio/metabolismo , Vicia faba/fisiologia
7.
BMC Plant Biol ; 19(1): 57, 2019 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-30727960

RESUMO

BACKGROUND: Sugar beet is a highly salt-tolerant crop. However, its ability to withstand high salinity is reduced compared to sea beet, a wild ancestor of all beet crops. The aim of this study was to investigate transcriptional patterns associated with physiological, cytological and biochemical mechanisms involved in salt response in these closely related subspecies. Salt acclimation strategies were assessed in plants subjected to either gradually increasing salt levels (salt-stress) or in excised leaves, exposed instantly to salinity (salt-shock). RESULT: The majority of DEGs was down-regulated under stress, which may lead to certain aspects of metabolism being reduced in this treatment, as exemplified by lowered transpiration and photosynthesis. This effect was more pronounced in sugar beet. Additionally, sugar beet, but not sea beet, growth was restricted. Silencing of genes encoding numerous transcription factors and signaling proteins was observed, concomitantly with the up-regulation of lipid transfer protein-encoding genes and those coding for NRTs. Bark storage protein genes were up-regulated in sugar beet to the level observed in unstressed sea beet. Osmotic adjustment, manifested by increased water and proline content, occurred in salt-shocked leaves of both genotypes, due to the concerted activation of genes encoding aquaporins, ion channels and osmoprotectants synthesizing enzymes. bHLH137 was the only TF-encoding gene induced by salt in a dose-dependent manner irrespective of the mode of salt treatment. Moreover, the incidence of bHLH-binding motives in promoter regions of salinity-regulated genes was significantly greater than in non-regulated ones. CONCLUSIONS: Maintaining homeostasis under salt stress requires deeper transcriptomic changes in the sugar beet than in the sea beet. In both genotypes salt shock elicits greater transcriptomic changes than stress and it results in greater number of up-regulated genes compared to the latter. NRTs and bark storage protein may play a yet undefined role in salt stress-acclimation in beet. bHLH is a putative regulator of salt response in beet leaves and a promising candidate for further studies.


Assuntos
Beta vulgaris/metabolismo , Plantas Tolerantes a Sal/metabolismo , Ácido Abscísico/metabolismo , Beta vulgaris/anatomia & histologia , Beta vulgaris/genética , Beta vulgaris/fisiologia , Clorofila/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Genes de Plantas/fisiologia , Reguladores de Crescimento de Planta/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Prolina/metabolismo , Característica Quantitativa Herdável , Estresse Salino , Plantas Tolerantes a Sal/fisiologia
8.
Plant Physiol Biochem ; 136: 127-142, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30665058

RESUMO

Salt stress suppresses plant growth, development, and crop productivity. In this study, we characterized the role of TaZFP1, a C2H2 type-zinc finger protein family member of T. aestivum, in salt stress tolerance. TaZFP1 possesses a conserved C2H2 motif (CX2-4CX12HX3-5H) shared by plant ZFP proteins, translocates to the nucleus after endoplasmic reticulum (ER) assortment, and displays a ZF 3-D structure similar to its eukaryote homologs. The transcripts of TaZFP1 were upregulated during salt stress condition and this effect was restored under normal conditions. Compared to wild type (WT), the transgenic lines of TaZFP1 overexpression or knockdown displayed improved phenotypes, biomass, photosynthesis parameters (Pn, ΨPSII, and NPQ), osmolytes contents (i.e. proline and soluble sugar), and enhanced antioxidant enzyme (AE) activity following salt stress treatment. A set of genes associated with proline synthesis (i.e., NtP5CS1 and NtP5CS2) and encoding AEs (i.e., NtSOD2, NtCAT1, and NtPOD4) were upregulated in the salt-challenged transgenic lines of TaZFP1 expression. Additionally, the transgenic lines exhibited similar stomata movement patterns and leaf water retention properties under salinity conditions compared to those induced by exogenous abscisic acid (ABA) treatment, suggesting that the TaZFP1-mediated salt response is dependent on the ABA signaling. High throughput RNAseq analysis revealed significant alteration of gene transcription in transgenic lines upon salt stress. Among them, the differentially expressed genes (DEGs) represented by the gene ontology (GO) terms were associated with organic acid, carboxylic acid, carbohydrate, and coenzyme as well as organonitrogen compounds, translation, peptide metabolism, and peptide biosynthesis. A set of upregulated DEGs were found to be thylakoid- and photosystem-associated, which is consistent with the TaZFP1-mediated improvement in photosynthesis in salt-stressed transgenic lines. Our investigation indicated that the TaZFP1-mediated salt tolerance is ascribed to the regulation of gene functions related to photosynthesis, osmolytes metabolism and ROS homeostasis mediated by ABA signaling.


Assuntos
Genes de Plantas/genética , Fatores de Transcrição Kruppel-Like/fisiologia , Proteínas de Plantas/fisiologia , Plantas Tolerantes a Sal/genética , Triticum/genética , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Genes de Plantas/fisiologia , Fatores de Transcrição Kruppel-Like/genética , Fotossíntese/genética , Fotossíntese/fisiologia , Filogenia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Espécies Reativas de Oxigênio/metabolismo , Estresse Salino , Plantas Tolerantes a Sal/metabolismo , Plantas Tolerantes a Sal/fisiologia , Tabaco , Triticum/metabolismo , Triticum/fisiologia
9.
J Plant Physiol ; 233: 84-93, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30623878

RESUMO

NAC (NAM, ATAF1/2 and CUC2) proteins are key regulators of various plant stress tolerances. However, knowledge of NAC genes remains largely unknown in Miscanthus. Here, we characterized a novel NAC gene MlNAC10 from M. lutarioriparius than plays a role in abiotic stress tolerance. MlNAC10 encodes a nuclear-localized protein with a C-terminal transactivation domain, and has a specific binding affinity to the NAC recognition sequence (NACRS). Ectopic expression of MlNAC10 in Arabidopsis led to increased sensitivity to abscisic acid (ABA) at early seedling growth stages. In addition, the proline content was significantly increased and the reactive oxygen species (ROS) scavenging capability was significantly enhanced in MlNAC10 overexpression lines under ABA treatment. Moreover, the drought and salt stress tolerance was significantly improved in MlNAC10 overexpression lines. Consistently, the activities of three antioxidant enzymes, namely catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD), were dramatically stimulated in the overexpression lines compared to the wild type (WT). Correspondingly, the accumulation of ROS was dramatically decreased and malondialdehyde (MDA) was accumulated at a much lower level in the transgenic lines. Meanwhile, the expression of six abiotic stress-related genes was dramatically stimulated in the overexpression lines in comparison to the WT. Together, our results demonstrated that MlNAC10 acts as an important regulator of drought and salinity stress tolerance by stimulating antioxidant enzymes and alleviating ROS damage via the ABA signaling pathway.


Assuntos
Proteínas de Plantas/fisiologia , Poaceae/genética , Plantas Tolerantes a Sal/genética , Fatores de Transcrição/fisiologia , Ácido Abscísico/metabolismo , Arabidopsis , Desidratação , Regulação da Expressão Gênica de Plantas , Filogenia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Poaceae/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Plantas Tolerantes a Sal/fisiologia , Fatores de Transcrição/genética
10.
Ecotoxicol Environ Saf ; 172: 45-52, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30677744

RESUMO

Salinity represents one of the environmental conditions with adverse effects on the productivity of most crops throughout the world. The response of plants to salt stress is of great interest for research to understand the mechanism involved in tolerance to salinity and highlight insights into the improvement of salt tolerance-crops of importance. In this study, the effect of salt stress was observed in wild and cultivated populations of P. oleracea originated from Tunisia and Italy. The results showed that at various concentrations of NaCl (0 mM, 50 mM, 100 mM and 150 mM), salinity has led to changes in growth parameters marked mainly by an increase in fresh and dry biomass. Beside, one of the salinity-induced side effects corresponds to the competition of Na+ and K+ ions for potassium root transporters. Our results suggested that purslane deployed an important element of tolerance such as the transporters ability to discriminate cations. In addition, the variation of PC5S gene expression tested by semi-quantitative RT-PCR revealed that proline synthesis is important in plants adaptation in saline conditions. A correlation between the gene expression varying by population and saline concentration and the level of proline assayed on the leaves of P. oleracea was highlighted.


Assuntos
Portulaca/fisiologia , Estresse Salino , Estresse Fisiológico , Adaptação Fisiológica , Biomassa , Produtos Agrícolas/metabolismo , Itália , Folhas de Planta/metabolismo , Portulaca/genética , Portulaca/metabolismo , Potássio/metabolismo , Prolina/metabolismo , Tolerância ao Sal/genética , Plantas Tolerantes a Sal/genética , Plantas Tolerantes a Sal/metabolismo , Plantas Tolerantes a Sal/fisiologia , Sódio/metabolismo , Cloreto de Sódio/farmacologia , Tunísia
11.
Plant Sci ; 278: 54-63, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30471729

RESUMO

Sporobolus virginicus is a halophytic C4 grass found worldwide, from tropical to warm temperate regions. One Japanese genotype showed a salinity tolerance up to 1.5 M NaCl, a three-fold higher concentration than the salinity of sea water. To identify the key genes involved in the regulation of salt tolerance in S. virginicus, we produced 3500 independent transgenic Arabidopsis lines expressing random cDNA from S. virginicus and screened 10 lines which showed enhanced salt tolerance compared with the wild type in a medium containing 150 mM NaCl. Among the selected lines, two contained cDNA coding glycine-rich RNA-binding proteins (SvGRP1 and SvGRP2). This is the first reports on the function of GRPs from halophytes in salt tolerance though reports have shown GRPs are involved in diverse biological and biochemical processes including salt tolerance in Arabidopsis and some other glycophytes. Transcriptomic analysis and GO enrichment analysis of SvGRP1-expressing Arabidopsis under salt stress revealed upregulation of polyol and downregulation of glucosinolate and indole acetic acid biosynthesis/metabolic pathways. Metabolomic analysis of the SvGRP1-transformant suggested that the increase in 3-aminoppropanoic acid, citramalic acid, and isocitric acid content was associated with enhanced salt tolerance. These findings could provide novel insight into the roles of GRPs in plant salt tolerance.


Assuntos
Proteínas de Plantas/fisiologia , Proteínas de Ligação a RNA/fisiologia , Tolerância ao Sal/genética , Plantas Tolerantes a Sal/genética , Sequência de Aminoácidos , Arabidopsis/genética , Perfilação da Expressão Gênica , Genótipo , Metaboloma , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/fisiologia , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/genética , Plantas Tolerantes a Sal/fisiologia , Alinhamento de Sequência
12.
J Plant Physiol ; 232: 141-150, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30537601

RESUMO

Sesuvium portulacastrum, an important mangrove-associated true halophyte belongs to the family Aizoaceae, has excellent salt tolerance. Chloroplasts are the most sensitive organelles involved in the response to salinity. However, the regulation mechanism of chloroplasts of S. portulacastrum under salinity stress has not been reported. In this study, morphological and physiological analyses of leaves and comparative proteomics of chloroplasts isolated from the leaves of S. portulacastrum under different NaCl treatments were performed. Our results showed that the thickness of the palisade tissue, the leaf area, the maximum photochemical efficiency of photosystem II, and the electron transport rate increased remarkably after the plants were subjected to differential saline environments, indicating that salinity can increase photosynthetic efficiency and improve the growth of S. portulacastrum. Subsequently, 55 differentially expressed protein species (DEPs) from the chloroplasts of S. portulacastrum under differential salt conditions were positively identified by mass spectrometry. These DEPs were involved in multiple metabolic pathways, such as photosynthesis, carbon metabolism, ATP synthesis and the cell structure. Among these DEPs, the abundance of most proteins was induced by salt stress. Based on a combination of the morphological and physiological data, as well as the chloroplast proteome results, we speculated that S. portulacastrum can maintain photosynthetic efficiency and growth by maintaining the stability of the photosystem II complex, promoting the photochemical reaction rate, enhancing carbon fixation, developing plastoglobules, and preserving the biomembrane system of chloroplasts under salt stress.


Assuntos
Aizoaceae/fisiologia , Cloroplastos/fisiologia , Aizoaceae/metabolismo , Clorofila/metabolismo , Cloroplastos/metabolismo , Fotossíntese , Proteômica , Reação em Cadeia da Polimerase em Tempo Real , Estresse Salino , Plantas Tolerantes a Sal/metabolismo , Plantas Tolerantes a Sal/fisiologia , Solo
13.
Microbiol Res ; 215: 89-101, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30172313

RESUMO

Soil salinity is one of the major limitations that affects both plant and its soil environment, leading to reduced agricultural production. Evaluation of stress severity by plant physical and biochemical characteristics is an established way to study plant-salt stress interaction, but the halotolerant properties of plant growth promoting bacteria (PGPB) along with plant growth promotion is less studied till date. The aim of the present study was to elucidate the strategy, used by ACC deaminase-containing halotolerant Brevibacterium linens RS16 to confer salt stress tolerance in moderately salt-tolerant (FL478) and salt-sensitive (IR29) rice (Oryza sativa L.) cultivars. The plants were exposed to salt stress using 0, 50, and 100 mM of NaCl with and without bacteria. Plant physiological and biochemical characteristics were estimated after 1, 5, 10 days of stress application. H+ ATPase activity and the presence of hydroxyectoine gene (ectD) that is responsible for compatible solute accumulation were also analyzed in bacteria. The height and dry mass of bacteria inoculated plants significantly increased compared to salt-stressed plants, and the differences increased in time dependent manner. Bacteria priming reduced the plant antioxidant enzyme activity, lipid peroxidation and it also regulated the salt accumulation by modulating vacuolar H+ ATPase activity. ATPase activity and presence of hydroxyectoine gene in RS16 might have played a vital role in providing salt tolerance in bacteria inoculated rice cultivars. We conclude that dual benefits provided by the halotolerant plant growth promoting bacteria (PGPB) can provide a major way to improve rice yields in saline soil.


Assuntos
Antioxidantes/metabolismo , Brevibacterium/fisiologia , Oryza/microbiologia , Oryza/fisiologia , Desenvolvimento Vegetal/fisiologia , ATPases Translocadoras de Prótons/metabolismo , Plantas Tolerantes a Sal/microbiologia , Plantas Tolerantes a Sal/fisiologia , Diamino Aminoácidos/genética , Biomassa , Brevibacterium/efeitos dos fármacos , Brevibacterium/enzimologia , Carbono-Carbono Liases , Catalase/metabolismo , Genes Bacterianos/genética , Genótipo , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos , Oryza/efeitos dos fármacos , Oryza/enzimologia , Estresse Oxidativo/fisiologia , Desenvolvimento Vegetal/efeitos dos fármacos , Folhas de Planta/enzimologia , Raízes de Plantas/microbiologia , Raízes de Plantas/fisiologia , Espécies Reativas de Oxigênio , Salinidade , Cloreto de Sódio/farmacologia , Solo , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/fisiologia
14.
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
15.
Syst Appl Microbiol ; 41(5): 516-527, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29934111

RESUMO

Actinobacteria from special habitats are of interest due to their producing of bioactive compounds and diverse ecological functions. However, little is known of the diversity and functional traits of actinobacteria inhabiting coastal salt marsh soils. We assessed actinobacterial diversity from eight coastal salt marsh rhizosphere soils from Jiangsu Province, China, using culture-based and 16S rRNA gene high throughput sequencing (HTS) methods, in addition to evaluating their plant growth-promoting (PGP) traits of isolates. Actinobacterial sequences represented 2.8%-43.0% of rhizosphere bacterial communities, as determined by HTS technique. The actinobacteria community comprised 34 families and 79 genera. In addition, 196 actinobacterial isolates were obtained, of which 92 representative isolates were selected for further 16S rRNA gene sequencing and phylogenetic analysis. The 92 strains comprised seven suborders, 12 families, and 20 genera that included several potential novel species. All representative strains were tested for their ability of producing indole acetic acid (IAA), siderophores, 1-aminocyclopropane-1-carboxylate deaminase (ACCD), hydrolytic enzymes, and phosphate solubilization. Based on the presence of multiple PGP traits, two strains, Streptomyces sp. KLBMP S0051 and Micromonospora sp. KLBMP S0019 were selected for inoculation of wheat seeds grown under salt stress. Both strains promoted seed germination, and KLBMP S0019 significantly enhanced seedling growth under NaCl stress. Our study demonstrates that coastal salt marsh rhizosphere soils harbor a diverse reservoir of actinobacteria that are potential resources for the discovery of novel species and functions. Moreover, several of the isolates identified here are good candidates as PGP bacteria that may contribute to plant adaptions to saline soils.


Assuntos
Actinobacteria/classificação , Actinobacteria/metabolismo , Filogenia , Reguladores de Crescimento de Planta/metabolismo , Rizosfera , Plantas Tolerantes a Sal/microbiologia , Áreas Alagadas , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Adaptação Fisiológica , Proteínas de Bactérias/metabolismo , Biodiversidade , China , DNA Bacteriano/genética , Hidrolases/metabolismo , Oceanos e Mares , RNA Ribossômico 16S/genética , Plantas Tolerantes a Sal/fisiologia , Análise de Sequência de DNA , Cloreto de Sódio , Microbiologia do Solo , Estresse Fisiológico , Triticum/crescimento & desenvolvimento , Triticum/microbiologia , Triticum/fisiologia
16.
Biotechnol Lett ; 40(8): 1159-1165, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29858710

RESUMO

Salt stress is considered one of the main abiotic factors to limit crop growth and productivity by affecting morpho-physiological and biochemical processes. Genetically, a number of salt tolerant Brassica varieties have been developed and introduced, but breeding of such varieties is time consuming. Therefore, current focus is on transgenic technology, which plays an important role in the development of salt tolerant varieties. Various salt tolerant genes have been characterized and incorporated into Brassica. Therefore, such genetic transformation of Brassica species is a significant step for improvement of crops, as well as conferring salt stress resistance qualities to Brassica species. Complete genome sequencing has made the task of genetically transforming Brassica species easier, by identifying desired candidate genes. The present review discusses relevant information about the principles which should be employed to develop transgenic Brassica species, and also will recommend tools for improved tolerance to salinity.


Assuntos
Brassica , Plantas Geneticamente Modificadas , Tolerância ao Sal/genética , Plantas Tolerantes a Sal , Estresse Fisiológico , Brassica/genética , Brassica/fisiologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Salinidade , Plantas Tolerantes a Sal/genética , Plantas Tolerantes a Sal/fisiologia , Cloreto de Sódio , Estresse Fisiológico/genética , Estresse Fisiológico/fisiologia
17.
Plant Sci ; 272: 173-178, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29807589

RESUMO

We recently identified two behaviours in cultured cells of the salt accumulating halophyte Cakile maritima: one related to a sustained depolarization due to Na+ influx through the non-selective cation channels leading to programmed cell death of these cells, a second one related to a transient depolarization allowing cells to survive (Ben Hamed-Laouti, 2016). In this study, we considered at the cellular level mechanisms that could participate to the exclusion of Na+ out of the cell and thus participate in the regulation of the internal contents of Na+ and cell survival. Upon addition of NaCl in the culture medium of suspension cells of C. maritima, we observed a rapid influx of Na+ followed by an efflux dependent of the activity of plasma membrane H+-ATPases, in accordance with the functioning of a Na+/H+ antiporter and the ability of some cells to repolarize. The Na+ efflux was shown to be dependent on Na+-dependent on Ca2+ influx like the SOS1 Na+/H+ antiporter. We further could observe in response to salt addition, an early production of singlet oxygen (1O2) probably due to peroxidase activities. This early 1O2 production seemed to be a prerequisite to the Na+ efflux. Our findings suggest that in addition to the pathway leading to PCD (Ben Hamed-Laouti, 2016), a second pathway comprising an SOS-like system could participate to the survival of a part of the C. maritima cultured cells challenged by salt stress.


Assuntos
Brassicaceae/metabolismo , Plantas Tolerantes a Sal/metabolismo , Brassicaceae/citologia , Brassicaceae/fisiologia , Células Cultivadas , Potenciais da Membrana , Redes e Vias Metabólicas/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Tolerância ao Sal/fisiologia , Plantas Tolerantes a Sal/citologia , Plantas Tolerantes a Sal/fisiologia , Sódio/metabolismo , Trocadores de Sódio-Hidrogênio/metabolismo , Superóxidos/metabolismo
18.
J Appl Microbiol ; 124(6): 1566-1579, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29444380

RESUMO

AIMS: The study was planned to characterize Planomicrobium sp. MSSA-10 for plant-beneficial traits and to evaluate its inoculation impact on physiology of pea plants under different salinity levels. METHODS AND RESULTS: Strain MSSA-10 was isolated from pea rhizosphere and identified by the analysis of 16S rRNA gene sequence. The strain demonstrated phosphate solubilization and auxin production up to 2 mol l-1 NaCl and exhibited 1-aminocyclopropane-1-carboxylic acid deaminase activity up to 1·5 mol l-1 salt. In an inoculation experiment under different salinity regimes, a significant increase in growth was observed associated with decreased levels of reactive oxygen species and enhanced antioxidative enzyme activities. The strain also promoted the translocation of nutrients in plants with subsequent increase in chlorophyll and protein contents as compared to noninoculated plants. It has been observed that rifampicin-resistant derivatives of MSSA-10 were able to survive for 30 days at optimum cell density with pea rhizosphere. CONCLUSION: Growth-stimulating effect of MSSA-10 on pea plants may be attributed to its rhizosphere competence, nutrient mobilization and modulation of plant oxidative damage repair mechanisms under saline environment. SIGNIFICANCE AND IMPACT OF THE STUDY: Planomicrobium sp. MSSA-10 might be used as potent bioinoculant to relieve pea plants from deleterious effects of salinity.


Assuntos
Estresse Oxidativo , Ervilhas , Planococáceas , Tolerância ao Sal/fisiologia , Plantas Tolerantes a Sal , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Ervilhas/efeitos dos fármacos , Ervilhas/microbiologia , Ervilhas/fisiologia , Planococáceas/isolamento & purificação , Planococáceas/fisiologia , Rizosfera , Plantas Tolerantes a Sal/efeitos dos fármacos , Plantas Tolerantes a Sal/microbiologia , Plantas Tolerantes a Sal/fisiologia , Cloreto de Sódio/toxicidade
19.
Plant Mol Biol ; 96(3): 305-314, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29322303

RESUMO

KEY MESSAGE: We studied the salt stress tolerance of two accessions isolated from different areas of the world (Norway and Tunisia) and characterized the mechanism(s) regulating salt stress in Brachypodium sylvaticum Osl1 and Ain1. Perennial grasses are widely grown in different parts of the world as an important feedstock for renewable energy. Their perennial nature that reduces management practices and use of energy and agrochemicals give these biomass crops advantages when dealing with modern agriculture challenges such as soil erosion, increase in salinized marginal lands and the runoff of nutrients. Brachypodium sylvaticum is a perennial grass that was recently suggested as a suitable model for the study of biomass plant production and renewable energy. However, its plasticity to abiotic stress is not yet clear. We studied the salt stress tolerance of two accessions isolated from different areas of the world and characterized the mechanism(s) regulating salt stress in B. sylvaticum Osl1, originated from Oslo, Norway and Ain1, originated from Ain-Durham, Tunisia. Osl1 limited sodium transport from root to shoot, maintaining a better K/Na homeostasis and preventing toxicity damage in the shoot. This was accompanied by higher expression of HKT8 and SOS1 transporters in Osl1 as compared to Ain1. In addition, Osl1 salt tolerance was accompanied by higher abundance of the vacuolar proton pump pyrophosphatase and Na+/H+ antiporters (NHXs) leading to a better vacuolar pH homeostasis, efficient compartmentation of Na+ in the root vacuoles and salt tolerance. Although preliminary, our results further support previous results highlighting the role of Na+ transport systems in plant salt tolerance. The identification of salt tolerant and sensitive B. sylvaticum accessions can provide an experimental system for the study of the mechanisms and regulatory networks associated with stress tolerance in perennials grass.


Assuntos
Brachypodium/fisiologia , Tolerância ao Sal/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Brachypodium/classificação , Brachypodium/efeitos dos fármacos , Plantas Tolerantes a Sal/efeitos dos fármacos , Plantas Tolerantes a Sal/fisiologia , Estresse Fisiológico/efeitos dos fármacos
20.
Microbiol Res ; 206: 25-32, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29146257

RESUMO

Plant growth and yield is adversely affected by soil salinity. Salt tolerant plant growth-promoting rhizobacteria (PGPR) strain IG 3 was isolated from rhizosphere of wheat plants. The isolate IG 3 was able to grow in presence of NaCl ranging from 0 to 20% in Luria Bertani medium. The present study was planned to evaluate the role of inoculation of PGPR strain IG 3 and its efficacy in augmenting salt tolerance in oat (Avena sativa) under NaCl stress (100mM). The physiological parameter such as shoot length, root length, shoot dry weight, root dry weight and relative water content (RWC) were remarkably higher in IG 3 inoculated plants in comparison to un-inoculated plants under NaCl stress. Similarly, the biochemical parameters such as proline content, electrolyte leakage and malondialdehyde (MDA) content and activities of antioxidant enzymes were analyzed and found to be notably lesser in IG 3 inoculated oat plants in contrast to un-inoculated plants under salt stress. Inoculation of IG 3 strain to oat seedlings under salt stress positively modulated the expression profile of rbcL and WRKY1 genes. Root colonization of root surface and interior was demonstrated using scanning electron microscopy and tetrazolium staining, respectively. Due these outcomes, it could be implicated that inoculation of PGPR strain IG 3 enhanced plant growth under salt stress condition. This study demonstrates that PGPR play an imperative function in stimulating salt tolerance in plants and can be used as biofertilizer to enhance growth of crops in saline areas.


Assuntos
Avena/microbiologia , Klebsiella/fisiologia , Desenvolvimento Vegetal , Plantas Tolerantes a Sal/efeitos dos fármacos , Plantas Tolerantes a Sal/fisiologia , Plântula/efeitos dos fármacos , Plântula/microbiologia , Cloreto de Sódio/farmacologia , Avena/química , Avena/efeitos dos fármacos , Avena/fisiologia , Clorofila/análise , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Genes de Plantas/genética , Índia , Klebsiella/isolamento & purificação , Microscopia Eletrônica de Varredura , Estresse Oxidativo/fisiologia , Peroxidase/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/citologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/microbiologia , Rizosfera , Salinidade , Plantas Tolerantes a Sal/microbiologia , Plântula/citologia , Plântula/fisiologia , Solo/química , Microbiologia do Solo , Estresse Fisiológico , Superóxido Dismutase/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Triticum/microbiologia
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