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1.
Int J Mol Sci ; 22(16)2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-34445454

RESUMO

The basic helix-loop-helix (bHLH) family of transcription factors is one of the most significant and biggest in plants. It is involved in the regulation of both growth and development, as well as stress response. Numerous members of the bHLH family have been found and characterized in woody plants in recent years. However, no systematic study of the bHLH gene family has been published for Hibiscus hamabo Sieb. et Zucc. In this research, we identified 162 bHLH proteins (HhbHLHs) from the genomic and transcriptomic datasets of H. hamabo, which were phylogenetically divided into 19 subfamilies. According to a gene structural study, the number of exon-introns in HhbHLHs varied between zero and seventeen. MEME research revealed that the majority of HhbHLH proteins contained three conserved motifs, 1, 4, and 5. The examination of promoter cis-elements revealed that the majority of HhbHLH genes had several cis-elements involved in plant growth and development and abiotic stress responses. In addition, the overexpression of HhbHLH2 increased salt and drought stress tolerance in Arabidopsis.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos , Regulação da Expressão Gênica de Plantas , Hibiscus , Proteínas de Plantas , Estresse Salino , Fatores de Transcrição Hélice-Alça-Hélice Básicos/biossíntese , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Desidratação/genética , Desidratação/metabolismo , Estudo de Associação Genômica Ampla , Hibiscus/genética , Hibiscus/metabolismo , Proteínas de Plantas/biossíntese , Proteínas de Plantas/genética
2.
Int J Mol Sci ; 22(15)2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-34360759

RESUMO

Salt and osmotic stress are the main abiotic stress factors affecting plant root growth and architecture. We investigated the effect of salt (100 mM NaCl) and osmotic (200 mM mannitol) stress on the auxin metabolome by UHPLC-MS/MS, auxin distribution by confocal microscopy, and transcript levels of selected genes by qRT-PCR in Arabidopsis thaliana ecotype Columbia-0 (Col-0) and DR5rev::GFP (DR5) line. During long-term stress (13 days), a stability of the auxin metabolome and a tendency to increase indole-3-acetic acid (IAA) were observed, especially during salt stress. Short-term stress (3 h) caused significant changes in the auxin metabolome, especially NaCl treatment resulted in a significant reduction of IAA. The data derived from auxin profiling were consistent with gene expressions showing the most striking changes in the transcripts of YUC, GH3, and UGT transcripts, suggesting disruption of auxin biosynthesis, but especially in the processes of amide and ester conjugation. These data were consistent with the auxin distribution observed in the DR5 line. Moreover, NaCl treatment caused a redistribution of auxin signals from the quiescent center and the inner layers of the root cap to the epidermal and cortical cells of the root elongation zone. The distribution of PIN proteins was also disrupted by salt stress; in particular, PIN2 was suppressed, even after 5 min of treatment. Based on our results, the DR5 line was more sensitive to the applied stresses than Col-0, although both lines showed similar trends in root morphology, as well as transcriptome and metabolome parameters under stress conditions.


Assuntos
Proteínas de Arabidopsis/biossíntese , Arabidopsis/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ácidos Indolacéticos/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Estresse Salino/efeitos dos fármacos , Cloreto de Sódio/farmacologia
3.
J Plant Physiol ; 264: 153485, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34358945

RESUMO

Soil salinity is a global concern and often the primary factor contributing to land degradation, limiting crop growth and production. Alfalfa (Medicago sativa L.) is a low input high value forage legume with a wide adaptation. Examining the tissue-specific responses to salt stress will be important to understanding physiological changes of alfalfa. The responses of two alfalfa cultivars (salt tolerant 'Halo', salt intolerant 'Vernal') were studied for 12 weeks in five gradients of salt stress in a sand based hydroponic system in the greenhouse. The accumulation and localization of elements and organic compounds in different tissues of alfalfa under salt stress were evaluated using synchrotron beamlines. The pattern of chlorine accumulation for 'Halo' was: root > stem ~ leaf at 8 dSm-1, and root ~ leaf > stem at 12 dSm-1, potentially preventing toxic ion accumulation in leaf tissues. In contrast, for 'Vernal', it was leaf > stem ~ root at 8 dSm-1 and leaf > root ~ stem at 12 dSm-1. The distribution of chlorine in 'Halo' was relatively uniform in the leaf surface and vascular bundles of the stem. Amide concentration in the leaf and stem tissues was greater for 'Halo' than 'Vernal' at all salt gradients. This study determined that low ion accumulation in the shoot was a common strategy in salt tolerant alfalfa up to 8 dSm-1 of salt stress, which was then replaced by shoot tissue tolerance at 12 dSm-1.


Assuntos
Medicago sativa/metabolismo , Cálcio/análise , Cálcio/metabolismo , Cloro/análise , Cloro/metabolismo , Medicago sativa/química , Medicago sativa/fisiologia , Folhas de Planta/química , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Caules de Planta/química , Caules de Planta/metabolismo , Caules de Planta/fisiologia , Potássio/análise , Potássio/metabolismo , Estresse Salino , Tolerância ao Sal , Sódio/análise , Sódio/metabolismo
4.
Curr Microbiol ; 78(10): 3708-3719, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34427735

RESUMO

In the current study, fourteen bacterial strains were obtained in salt contaminated soils. The identification and characterization of the bacterial strains were performed by conventional and molecular techniques. According to the results of 16S rRNA gene sequence analysis, five genera (Bacillus, Staphylococcus, Oceanobacillus, Exiguobacterium, and Halobacillus) were identified with a homology of equal to 99% or higher similarity. Afterward, these fourteen halotolerant/halophilic bacterial strains were investigated for their plant growth promoting (PGP) traits including production of indole-3-acetic acid (IAA) and siderophore, activity of 1-aminocyclopropane-1-carboxylate (ACC) deaminase, fixation of nitrogen, and phosphate solubilization potential. Five of the bacterial strains possessing PGP traits were tested for their effects on the growth of a salt sensitive plant (wheat) in a hydroponic system under salt stress (200 mM). Inoculation of five bacterial strains under salt stress significantly enhanced plant weight (Triticum aestivum) ranged from 71.18 to 89.04%. Salt stress amelioration potential of Oceanobacillus picturae and Staphylococcus succinus on T. aestivum has been shown for the first time in this study. In non-saline soil, the promising effect of plant growth bacteria is clear; however, in saline soil, the use of PGP halophilic and halotolerant bacteria can increase the productivity of salt sensitive plants. Therefore, the novel halophilic and halotolerant bacteria that promote plant growth can be developed for agricultural uses in saline soils.


Assuntos
Bactérias , Microbiologia do Solo , Bacillaceae , Bactérias/genética , Raízes de Plantas , RNA Ribossômico 16S/genética , Estresse Salino , Staphylococcus
5.
Int J Mol Sci ; 22(16)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34445127

RESUMO

The common ice plant (Mesembryanthemum crystallinum L.) is a facultative crassulacean acid metabolism (CAM) plant, and its ability to recover from stress-induced CAM has been confirmed. We analysed the photosynthetic metabolism of this plant during the 72-h response period following salinity stress removal from three perspectives. In plants under salinity stress (CAM) we found a decline of the quantum efficiencies of PSII (Y(II)) and PSI (Y(I)) by 17% and 15%, respectively, and an increase in nonphotochemical quenching (NPQ) by almost 25% in comparison to untreated control. However, 48 h after salinity stress removal, the PSII and PSI efficiencies, specifically Y(II) and Y(I), elevated nonphotochemical quenching (NPQ) and donor side limitation of PSI (YND), were restored to the level observed in control (C3 plants). Swelling of the thylakoid membranes, as well as changes in starch grain quantity and size, have been found to be components of the salinity stress response in CAM plants. Salinity stress induced an over 3-fold increase in average starch area and over 50% decline of average seed number in comparison to untreated control. However, in plants withdrawn from salinity stress, during the first 24 h of recovery, we observed chloroplast ultrastructures closely resembling those found in intact (control) ice plants. Rapid changes in photosystem functionality and chloroplast ultrastructure were accompanied by the induction of the expression (within 24 h) of structural genes related to the PSI and PSII reaction centres, including PSAA, PSAB, PSBA (D1), PSBD (D2) and cp43. Our findings describe one of the most flexible photosynthetic metabolic pathways among facultative CAM plants and reveal the extent of the plasticity of the photosynthetic metabolism and related structures in the common ice plant.


Assuntos
Metabolismo Ácido das Crassuláceas/genética , Mesembryanthemum/genética , Fotossíntese/genética , Estresse Salino/genética , Cloroplastos/efeitos dos fármacos , Cloroplastos/genética , Metabolismo Ácido das Crassuláceas/efeitos dos fármacos , Mesembryanthemum/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Plastídeos/efeitos dos fármacos , Plastídeos/genética , Salinidade , Estresse Salino/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Amido/genética , Tilacoides/efeitos dos fármacos , Tilacoides/genética
6.
Int J Mol Sci ; 22(16)2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34445331

RESUMO

Plant WRKY transcription factors play crucial roles in plant growth and development, as well as plant responses to biotic and abiotic stresses. In this study, we identified and characterized a WRKY transcription factor in rice, OsWRKY50. OsWRKY50 functions as a transcriptional repressor in the nucleus. The transcription of OsWRKY50 was repressed under salt stress conditions, but activated after abscisic acid (ABA) treatment. OsWRKY50-overexpression (OsWRKY50-OX) plants displayed increased tolerance to salt stress compared to wild type and control plants. The expression of OsLEA3, OsRAB21, OsHKT1;5, and OsP5CS1 in OsWRKY50-OX were much higher than wild type and control plants under salt stress. Furthermore, OsWRKY50-OX displayed hyposensitivity to ABA-regulated seed germination and seedling establishment. The protoplast-based transient expression system and yeast hybrid assay demonstrated that OsWRKY50 directly binds to the promoter of OsNCED5, and thus further inhibits its transcription. Taken together, our results demonstrate that rice transcription repressor OsWRKY50 mediates ABA-dependent seed germination and seedling growth and enhances salt stress tolerance via an ABA-independent pathway.


Assuntos
Ácido Abscísico/farmacologia , Oryza , Tolerância ao Sal , Fatores de Transcrição/fisiologia , Proteínas de Arabidopsis/genética , Clonagem Molecular , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Germinação/efeitos dos fármacos , Germinação/genética , Oryza/efeitos dos fármacos , Oryza/genética , Oryza/crescimento & desenvolvimento , Filogenia , Desenvolvimento Vegetal/efeitos dos fármacos , Desenvolvimento Vegetal/genética , Proteínas de Plantas/genética , Proteínas de Plantas/fisiologia , Plantas Geneticamente Modificadas , Estresse Salino/efeitos dos fármacos , Estresse Salino/genética , Tolerância ao Sal/efeitos dos fármacos , Tolerância ao Sal/genética , Plântula/efeitos dos fármacos , Plântula/genética , Plântula/crescimento & desenvolvimento , Análise de Sequência de DNA , Homologia de Sequência , Fatores de Transcrição/genética
7.
J Genet ; 1002021.
Artigo em Inglês | MEDLINE | ID: mdl-34282732

RESUMO

Rice is one of the most important cereals of the world, with a substantial amount of genetic variation, and a staple food for more than half of the world's population. Salinity is the second most important abiotic stress after drought that adversely affects rice production globally. Both the seedling and reproductive stages are extremely sensitive to salinity but tolerant at the reproductive stage which is most crucial, as it translates into grain yield. Therefore, it is more important to identify the underlying factors of tolerance at the reproductive stage as a necessary step towards improving varieties for salinity environments. However, because of the difficulties in phenotyping protocols of salinity tolerance screening at the reproductive stage, only a few studies exist on this aspect. In view of this, a study involving 188 F4 rice lines derived from a cross CSR28 × Sadri along with the parents was carried out for phenotyping using a novel screening approach for the reproductive stage in salinity conditions and genotyping by SNP markers (Infinium Illumina 6K SNP chip) to construct a high-saturation linkage map. Quantitative trait loci analysis in an F4 population for physiological traits (chlorophyll a, chlorophyll b and carotenoid) and agronomic traits (plant height, filled grain number, grain yield and spikelet fertility percentage) led to the identification of 14 QTLs with an LOD range of 2.72-4.46 explaining phenotypic variation of 5.29-24.86% on chromosomes 1, 2, 3, 5, 6, 7 and 8. Tolerant alleles were contributed by both CSR28 and Sadri. The results indicated that both physiological and agronomic traits were involved in salinity tolerance at the reproductive stage and majority of the QTLs identified in this study are reported for the first time.


Assuntos
Oryza/genética , Locos de Características Quantitativas/genética , Estresse Salino/genética , Tolerância ao Sal/genética , Alelos , Mapeamento Cromossômico/métodos , Cromossomos de Plantas , Genótipo , Oryza/crescimento & desenvolvimento , Oryza/fisiologia , Fenótipo , Reprodução/genética , Reprodução/fisiologia , Plântula/genética
8.
Int J Mol Sci ; 22(11)2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34199464

RESUMO

The influence of salt stress on gene expression, promoter methylation, and enzymatic activity of the mitochondrial and cytosolic forms of aconitase and fumarase has been investigated in maize (Zea mays L.) seedlings. The incubation of maize seedlings in 150-mM NaCl solution resulted in a several-fold increase of the mitochondrial activities of aconitase and fumarase that peaked at 6 h of NaCl treatment, while the cytosolic activity of aconitase and fumarase decreased. This corresponded to the decrease in promoter methylation of the genes Aco1 and Fum1 encoding the mitochondrial forms of these enzymes and the increase in promoter methylation of the genes Aco2 and Fum2 encoding the cytosolic forms. The pattern of expression of the genes encoding the mitochondrial forms of aconitase and fumarase corresponded to the profile of the increase of the stress marker gene ZmCOI6.1. It is concluded that the mitochondrial and cytosolic forms of aconitase and fumarase are regulated via the epigenetic mechanism of promoter methylation of their genes in the opposite ways in response to salt stress. The role of the mitochondrial isoforms of aconitase and fumarase in the elevation of respiration under salt stress is discussed.


Assuntos
Aconitato Hidratase/genética , Metilação de DNA/genética , Fumarato Hidratase/genética , Estresse Salino/genética , Citosol/enzimologia , Regulação da Expressão Gênica de Plantas/genética , Mitocôndrias/enzimologia , Regiões Promotoras Genéticas/genética , Zea mays/genética , Zea mays/crescimento & desenvolvimento
9.
Planta ; 254(2): 24, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34224010

RESUMO

MAIN CONCLUSION: An overview is presented of recent advances in our knowledge of responses and mechanisms rendering adaptation to saline conditions in sorghum. Different strategies deployed to enhance salinity stress tolerance in sorghum are also pointed out. Salinity stress is a growing problem worldwide. Sorghum is the fifth key crop among cereals. Understanding responses and tolerance strategies in sorghum would be therefore helpful effort for providing biomarkers for designing greatest salinity-tolerant sorghum genotypes. When sorghum exposed to salinity, salinity-tolerant genotypes most probably reprogram their gene expression to activate adaptive biochemical and physiological responses for survival. The review thus discusses the possible physiological and biochemical responses that confer salinity tolerance to sorghum under saline conditions. Although it is not characterized in sorghum, salinity perceiving and transmitting signals to downstream responses via signaling transduction pathways most likely are essential strategy for sorghum adaptation to salinity stress. Sorghum has also shown to withstand moderate saline environments and retain the germination, growth, and photosynthetic activities. Salinity-tolerant sorghum genotypes show the ability to exclude excessive Na+ from reaching shoots and induce ion homeostasis. Osmotic homeostasis and ROS detoxification are also evident as salinity tolerance strategies in sorghum. These above mechanisms lead to re-establishment of cellular ionic, osmotic, and redox homeostasis as well as photosynthesis efficiency. It is noteworthy that these mechanisms act individually or co-operatively to minimize the salinity hazards and enhance acclimation in sorghum. We conclude, however, that although these responses contribute to sorghum tolerance to salinity stress, they seem to be not adequate at higher concentrations of salinity, which agrees with sorghum ranking as moderately salinity-tolerant crop. Also, some of these tolerance strategies reported in other crops are not well studied and documented in sorghum, but most probably have roles in sorghum. Further improvement in sorghum salinity tolerance using different approaches is definitely necessary to meet the requirements of its harsh production environments, and therefore, these approaches are addressed.


Assuntos
Sorghum , Grão Comestível , Salinidade , Estresse Salino , Tolerância ao Sal , Sorghum/genética
10.
J Environ Manage ; 297: 113302, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34293671

RESUMO

High salt seriously destroys the stable interactions among key functional species of activated sludge, which in turn limits the performance of high-salinity wastewater biological treatment. In this study, pelletized Aspergillus tubingensis (AT) was used as a protective backbone structure for activated sludge under high-salinity stress, and a superior salt-tolerant AT-based aerobic granular sludge (AT-AGS) was developed. Results showed that the COD and NH4+-N removal efficiencies of salt-domesticated AT-AGS were 11.83% and 7.18% higher than those of salt-domesticated flocculent activated sludge (FAS) at 50 gNaCl/L salinity. Compared to the salt-domesticated FAS, salt-domesticated AT-AGS showed stronger biomass retention capacity (with a MLVSS concentration of 7.92 g/L) and higher metabolic activity (with a dehydrogenase activity of 48.06 mgTF/gVSS·h). AT modified the extracellular polymeric substances pattern of microbes, and the total extracellular polysaccharide content of AT-AGS (80.7 mg/gVSS) was nearly twice than that of FAS (46.3 mg/gVSS) after salt-domestication, which demonstrated that extracellular polysaccharide played a key role in keeping the system stable. The high-throughput sequencing analysis illustrated that AT contributed to maintain the microbial richness and diversity of AT-AGS in high-salt environment, and Marinobacterium (with a relative abundance of 32.04%) became the most predominant genus in salt-tolerant AT-AGS. This study provided a novel insight into enhancing the robustness of activated sludge under high-salinity stress.


Assuntos
Esgotos , Eliminação de Resíduos Líquidos , Aerobiose , Aspergillus , Reatores Biológicos , Estresse Salino , Águas Residuárias
11.
Molecules ; 26(13)2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34279430

RESUMO

High salt levels are one of the significant and major limiting factors on crop yield and productivity. Out of the available attempts made against high salt levels, engineered nanoparticles (NPs) have been widely employed and considered as effective strategies in this regard. Of these NPs, titanium dioxide nanoparticles (TiO2 NPs) and selenium functionalized using chitosan nanoparticles (Cs-Se NPs) were applied for a quite number of plants, but their potential roles for alleviating the adverse effects of salinity on stevia remains unclear. Stevia (Stevia rebaudiana Bertoni) is one of the reputed medicinal plants due to their diterpenoid steviol glycosides (stevioside and rebaudioside A). For this reason, the current study was designed to investigate the potential of TiO2 NPs (0, 100 and 200 mg L-1) and Cs-Se NPs (0, 10 and 20 mg L-1) to alleviate salt stress (0, 50 and 100 mM NaCl) in stevia. The findings of the study revealed that salinity decreased the growth and photosynthetic traits but resulted in substantial cell damage through increasing H2O2 and MDA content, as well as electrolyte leakage (EL). However, the application of TiO2 NPs (100 mg L-1) and Cs-Se NPs (20 mg L-1) increased the growth, photosynthetic performance and activity of antioxidant enzymes, and decreased the contents of H2O2, MDA and EL under the saline conditions. In addition to the enhanced growth and physiological performance of the plant, the essential oil content was also increased with the treatments of TiO2 (100 mg L-1) and Cs-Se NPs (20 mg L-1). In addition, the tested NPs treatments increased the concentration of stevioside (in the non-saline condition and under salinity stress) and rebaudioside A (under the salinity conditions) in stevia plants. Overall, the current findings suggest that especially 100 mg L-1 TiO2 NPs and 20 mg L-1 Cs-Se could be considered as promising agents in combating high levels of salinity in the case of stevia.


Assuntos
Quitosana/química , Nanopartículas/administração & dosagem , Folhas de Planta/crescimento & desenvolvimento , Estresse Salino/efeitos dos fármacos , Selênio/administração & dosagem , Stevia/crescimento & desenvolvimento , Titânio/administração & dosagem , Nanopartículas/química , Fotossíntese , Selênio/química , Stevia/efeitos dos fármacos , Titânio/química
12.
Plant Physiol Biochem ; 166: 789-798, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34218207

RESUMO

Soil salinity stress causes osmotic/ionic imbalances and induces oxidative stress that causes cellular structure damage, perturbs metabolism, antioxidant system (comprising enzymatic and non-enzymatic components) and hence inhibits plant growth performance. In this study, we used genome-wide association scan (GWAS) in 174 diverse spring barley accessions which were exposed to salt stress under field conditions at the vegetative stage to uncover the genetic basis of antioxidant components and agronomic traits. High activities of enzymatic and content of non-enzymatic antioxidants were observed under salt stress compared to control conditions. Under salt stress, all the agronomic and yield-related traits were significantly reduced. Six genomic regions were associated with antioxidants and agronomic traits under salt stress conditions which were found to be linked with candidate genes. Several significant associations were physically located inside or near genes which are potentially involved in antioxidants. Two candidate genes at 2H (40,659,364 bp) and 7H (416,743,127 bp) were found to be involved in Dihydroflavonol 4-reductase/flavanone protein and Glyceraldehyde-3-phosphate dehydrogenase, respectively. The allelic variation at SNP of BK_07 at 7H inside the GAPDH gene demonstrates a negative selection of accessions carrying A allele. This allele appears in cultivars with lower activity of enzymatic antioxidants e.g. superoxide dismutase and catalases under salt stress conditions. These accessions are predominantly two-rowed, cultivars, originated from Europe, and carrying photoperiod sensitive alleles. The detected associated molecular markers in this work are considered as an important source for selection of increased amount of antioxidant compounds in barley under stress conditions.


Assuntos
Hordeum , Alelos , Antioxidantes , Estudo de Associação Genômica Ampla , Hordeum/genética , Estresse Salino
13.
Sci Total Environ ; 796: 148979, 2021 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-34274671

RESUMO

The shift of microbial community and signaling molecules release were studied to explore the potential mechanism of anammox consortium under salt stress. Due to increased salinity, the abundance of "Candidatus Brocadia" decreased from 29.5% to 1.9%. "Candidatus Brocadia" was reduced by the salinity shock. Besides, "Candidatus Scalindua", marine anammox bacteria, was detected at 18 g L-1 NaCl and dominated the reactor. Principle coordinates analysis further proved that salinity was the driving force on the distribution and diversity of anammox consortium. Also, quorum sensing feedback mechanism of anammox bacteria under salt stress was investigated for the first time. The concentration of N-(3-oxohexanoyl)-DL-homoserine lactone (3OC6-HSL) increased from 0.27 ± 0.02 to 1.24 ± 0.09 µM at 7 to 9 g L-1 NaCl. The concentration of 3OC6-HSL maintained at a high level at 9 to 12 g L-1 NaCl. Nacylated-l-homoserine lactones (AHLs)-mediated QS became more active and then improved the coordinated interaction in anammox consortium. High concentration of AHLs promoted the bacteria to produce more extracellular polymeric substances, which increased the bacterial tolerance to salt stress.


Assuntos
Microbiota , Percepção de Quorum , Bactérias , Matriz Extracelular de Substâncias Poliméricas , Estresse Salino
14.
Nat Commun ; 12(1): 4433, 2021 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-34290242

RESUMO

The small, regulatory RNA RepG (Regulator of polymeric G-repeats) regulates the expression of the chemotaxis receptor TlpB in Helicobacter pylori by targeting a variable G-repeat in the tlpB mRNA leader. Here, we show that RepG additionally controls lipopolysaccharide (LPS) phase variation by also modulating the expression of a gene (hp0102) that is co-transcribed with tlpB. The hp0102 gene encodes a glycosyltransferase required for LPS O-chain biosynthesis and in vivo colonization of the mouse stomach. The G-repeat length defines a gradual (rather than ON/OFF) control of LPS biosynthesis by RepG, and leads to gradual resistance to a membrane-targeting antibiotic. Thus, RepG-mediated modulation of LPS structure might impact host immune recognition and antibiotic sensitivity, thereby helping H. pylori to adapt and persist in the host.


Assuntos
Farmacorresistência Bacteriana , Helicobacter pylori/fisiologia , Lipopolissacarídeos/biossíntese , RNA Bacteriano/metabolismo , Pequeno RNA não Traduzido/metabolismo , Regiões 5' não Traduzidas , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Infecções por Helicobacter/microbiologia , Helicobacter pylori/efeitos dos fármacos , Lipopolissacarídeos/química , Camundongos , Antígenos O/biossíntese , Antígenos O/química , Polimixina B/farmacologia , RNA Bacteriano/genética , Pequeno RNA não Traduzido/genética , Sequências Repetitivas de Ácido Nucleico , Estresse Salino , Estômago/microbiologia
15.
Int J Mol Sci ; 22(14)2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-34298928

RESUMO

Salt stress seriously restricts crop yield and quality, leading to an urgent need to understand its effects on plants and the mechanism of plant responses. Although phytohormones are crucial for plant responses to salt stress, the role of phytohormone signal transduction in the salt stress responses of stress-resistant species such as Sophora alopecuroides has not been reported. Herein, we combined transcriptome and metabolome analyses to evaluate expression changes of key genes and metabolites associated with plant hormone signal transduction in S. alopecuroides roots under salt stress for 0 h to 72 h. Auxin, cytokinin, brassinosteroid, and gibberellin signals were predominantly involved in regulating S. alopecuroides growth and recovery under salt stress. Ethylene and jasmonic acid signals may negatively regulate the response of S. alopecuroides to salt stress. Abscisic acid and salicylic acid are significantly upregulated under salt stress, and their signals may positively regulate the plant response to salt stress. Additionally, salicylic acid (SA) might regulate the balance between plant growth and resistance by preventing reduction in growth-promoting hormones and maintaining high levels of abscisic acid (ABA). This study provides insight into the mechanism of salt stress response in S. alopecuroides and the corresponding role of plant hormones, which is beneficial for crop resistance breeding.


Assuntos
Estresse Salino/genética , Transdução de Sinais/genética , Sophora/genética , Ácido Abscísico/metabolismo , Brassinosteroides/metabolismo , Citocininas/genética , Etilenos/metabolismo , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas/genética , Ácidos Indolacéticos/metabolismo , Melhoramento Vegetal/métodos , Reguladores de Crescimento de Plantas/genética , Proteínas de Plantas/genética , Ácido Salicílico/metabolismo , Tolerância ao Sal/genética , Sophora/metabolismo , Estresse Fisiológico/genética , Transcriptoma/genética , Regulação para Cima/genética
16.
BMC Plant Biol ; 21(1): 328, 2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34238224

RESUMO

BACKGROUND: MYB transcription factors are a kind of DNA binding protein that can specifically interact with the promoter region. Members of MYB TFs are widely involved in plant growth and development, secondary metabolism, stress response, and hormone signal transduction. However, there is no report of comprehensive bioinformatics analysis on the MYB family of Casuarina equisetifolia. RESULTS: In this study, bioinformatics methods were used to screen out 182 MYB transcription factors from the Casuarina equisetifolia genome database, including 69 1R-MYB, 107 R2R3-MYB, 4 R1R2R3-MYB, and 2 4R-MYB. The C. equisetifolia R2R3-MYB genes were divided into 29 groups based on the phylogenetic topology and the classification of the MYB superfamily in Arabidopsis thaliana, while the remaining MYB genes (1R-MYB, R1R2R3-MYB, and 4R-MYB) was divided into 19 groups. Moreover, the conserved motif and gene structure analysis shown that the members of the CeqMYBs were divided into the same subgroups with mostly similar gene structures. In addition, many conserved amino acids in the R2 and R3 domains of CeqMYBs by WebLogo analysis, especially tryptophan residues (W), with 3 conserved W in R2 repeat and 2 conserved W in R3 repeat. Combining promoter and GO annotation analysis, speculated on the various biological functions of CeqMYBs, thus 32 MYB genes were selected to further explore its response to salt stress by using qPCR analysis technique. Most CeqMYB genes were differentially regulated following multiple salt treatments. CONCLUSIONS: Seven genes (CeqMYB164, CeqMYB4, CeqMYB53, CeqMYB32, CeqMYB114, CeqMYB71 and CeqMYB177) were assigned to the "response to salt stress" by GO annotation. Among them, the expression level of CeqMYB4 was up-regulated under various salt treatments, indicating CeqMYB4 might participated in the response to salt stress. Our results provide important information for the biological function of C. equisetifolia, as well as offer candidate genes for further study of salt stress mechanism.


Assuntos
Arabidopsis/genética , Fagales/genética , Genes myb , Estresse Salino/genética , Tolerância ao Sal/genética , Fatores de Transcrição/genética , Mapeamento Cromossômico , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Estudo de Associação Genômica Ampla , Família Multigênica , Filogenia , Proteínas de Plantas/genética
17.
BMC Plant Biol ; 21(1): 331, 2021 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-34246235

RESUMO

BACKGROUND: As damage to the ecological environment continues to increase amid unreasonable amounts of irrigation, soil salinization has become a major challenge to agricultural development. Melatonin (MT) is a pleiotropic signal molecule and indole hormone, which alleviates the damage of abiotic stress to plants. MT has been confirmed to eliminate reactive oxygen species (ROS) by improving the antioxidant system and reducing oxidative damage under adversity. However, the mechanism by which exogenous MT mediates salt tolerance by regulating the photosynthetic capacity and ion balance of cotton seedlings still remains unknown. In this study, the regulatory effects of MT on the photosynthetic system, osmotic modulators, chloroplast, and anatomical structure of cotton seedlings were determined under 0-500 µM MT treatments with salt stress induced by treatment with 150 mM NaCl. RESULTS: Salt stress reduces the chlorophyll content, net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, PSII photochemical efficiency, PSII actual photochemical quantum yield, the apparent electron transfer efficiency, stomata opening, and biomass. In addition, it increases non-photochemical quenching. All of these responses were effectively alleviated by exogenous treatment with MT. Exogenous MT reduces oxidative damage and lipid peroxidation by reducing salt-induced ROS and protects the plasma membrane from oxidative toxicity. MT also reduces the osmotic pressure by reducing the salt-induced accumulation of Na+ and increasing the contents of K+ and proline. Exogenous MT can facilitate stomatal opening and protect the integrity of cotton chloroplast grana lamella structure and mitochondria under salt stress, protect the photosynthetic system of plants, and improve their biomass. An anatomical analysis of leaves and stems showed that MT can improve xylem and phloem and other properties and aides in the transportation of water, inorganic salts, and organic substances. Therefore, the application of MT attenuates salt-induced stress damage to plants. Treatment with exogenous MT positively increased the salt tolerance of cotton seedlings by improving their photosynthetic capacity, stomatal characteristics, ion balance, osmotic substance biosynthetic pathways, and chloroplast and anatomical structures (xylem vessels and phloem vessels). CONCLUSIONS: Our study attributes help to protect the structural stability of photosynthetic organs and increase the amount of material accumulation, thereby reducing salt-induced secondary stress. The mechanisms of MT-induced plant tolerance to salt stress provide a theoretical basis for the use of MT to alleviate salt stress caused by unreasonable irrigation, fertilization, and climate change.


Assuntos
Gossypium/metabolismo , Melatonina/metabolismo , Fotossíntese/efeitos dos fármacos , Reguladores de Crescimento de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Estresse Salino/efeitos dos fármacos , Tolerância ao Sal/efeitos dos fármacos , Produtos Agrícolas/metabolismo
18.
Int J Mol Sci ; 22(13)2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34201749

RESUMO

Plant abiotic stress responses are tightly regulated by different players at multiple levels. At transcriptional or post-transcriptional levels, several RNA binding proteins (RBPs) regulate stress response genes through RNA metabolism. They are increasingly recognized as critical modulators of a myriad of biological processes, including stress responses. Plant RBPs are heterogeneous with one or more conservative RNA motifs that constitute canonical/novel RNA binding domains (RBDs), which can bind to target RNAs to determine their regulation as per the plant requirements at given environmental conditions. Given its biological significance and possible consideration as a potential tool in genetic manipulation programs to improve key agronomic traits amidst frequent episodes of climate anomalies, studies concerning the identification and functional characterization of RBP candidate genes are steadily mounting. This paper presents a comprehensive overview of canonical and novel RBPs and their functions in major abiotic stresses including drought, heat, salt, and cold stress conditions. To some extent, we also briefly describe the basic motif structure of RBPs that would be useful in forthcoming studies. Additionally, we also collected RBP genes that were modulated by stress, but that lacked functional characterization, providing an impetus to conduct further research.


Assuntos
Proteínas de Plantas/química , Proteínas de Plantas/fisiologia , Proteínas de Ligação a RNA/química , Proteínas de Ligação a RNA/fisiologia , Estresse Fisiológico/fisiologia , Resposta ao Choque Frio/fisiologia , Secas , Resposta ao Choque Térmico/fisiologia , Domínios Proteicos , Salinidade , Estresse Salino/fisiologia
19.
Int J Mol Sci ; 22(13)2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34281289

RESUMO

Several recent studies have shown that citric acid/citrate (CA) can confer abiotic stress tolerance to plants. Exogenous CA application leads to improved growth and yield in crop plants under various abiotic stress conditions. Improved physiological outcomes are associated with higher photosynthetic rates, reduced reactive oxygen species, and better osmoregulation. Application of CA also induces antioxidant defense systems, promotes increased chlorophyll content, and affects secondary metabolism to limit plant growth restrictions under stress. In particular, CA has a major impact on relieving heavy metal stress by promoting precipitation, chelation, and sequestration of metal ions. This review summarizes the mechanisms that mediate CA-regulated changes in plants, primarily CA's involvement in the control of physiological and molecular processes in plants under abiotic stress conditions. We also review genetic engineering strategies for CA-mediated abiotic stress tolerance. Finally, we propose a model to explain how CA's position in complex metabolic networks involving the biosynthesis of phytohormones, amino acids, signaling molecules, and other secondary metabolites could explain some of its abiotic stress-ameliorating properties. This review summarizes our current understanding of CA-mediated abiotic stress tolerance and highlights areas where additional research is needed.


Assuntos
Ácido Cítrico/metabolismo , Ácido Cítrico/farmacologia , Plantas/efeitos dos fármacos , Plantas/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Adaptação Fisiológica/efeitos dos fármacos , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Secas , Engenharia Genética , Resposta ao Choque Térmico/efeitos dos fármacos , Inativação Metabólica , Metais Pesados/farmacocinética , Metais Pesados/toxicidade , Modelos Biológicos , Desenvolvimento Vegetal/efeitos dos fármacos , Reguladores de Crescimento de Plantas/metabolismo , Plantas/genética , Espécies Reativas de Oxigênio/metabolismo , Estresse Salino/efeitos dos fármacos , Estresse Fisiológico/genética
20.
Food Chem ; 361: 130177, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34077883

RESUMO

Carotenoid content in maize sprouts can be increased by NaCl stress, although high NaCl concentrations negatively impact plant growth. The effects of exogenous methyl jasmonate (MeJA) on contents of carotenoid and antioxidant capacity of yellow maize sprouts under NaCl stress were investigated. Our results showed that treatments of NaCl both alone and combined with MeJA enhanced the carotenoid accumulation in maize sprouts. Moreover, the carotenoid biosynthesis related genes showed different expression patterns under addition of MeJA treatment. Additionally, the combined treatment led to significantly higher content of most carotenoids profiles and the addition of MeJA could alleviate the harmful effect caused by NaCl stress. Furthermore, the combined treatment improved antioxidant enzyme activities and radical scavenging capacity. The results implied that MeJA is kind of effective plant growth regulator for enhancing carotenoid accumulation in maize sprouts by up-regulating the expression levels of key genes involved in carotenoid biosynthetic pathway.


Assuntos
Acetatos/farmacologia , Carotenoides/metabolismo , Ciclopentanos/farmacologia , Oxilipinas/farmacologia , Reguladores de Crescimento de Plantas/farmacologia , Cloreto de Sódio/farmacologia , Zea mays/efeitos dos fármacos , Antioxidantes/metabolismo , Enzimas/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Estresse Salino , Plântula/efeitos dos fármacos , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Zea mays/fisiologia
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