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1.
PLoS One ; 15(8): e0236129, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32760076

RESUMO

Salix matsudana, a member of Salicaceae, is an important ornamental tree in China. Because of its capability to tolerate high salt conditions, S. matsudana also plays an important ecological role when grown along Chinese coastal beaches, where the salinity content is high. Here, we aimed to elucidate the mechanism of higher salt tolerance in S. matsudana variety '9901' by identifying the associated genes through RNA sequencing and comparing differential gene expression between the S. matsudana salt-tolerant and salt-sensitive samples treated with 150 mM NaCl. Transcriptomic comparison of the roots of the two samples revealed 2174 and 3159 genes responsive to salt stress in salt-sensitive and salt-tolerant sample, respectively. Real-time polymerase chain reaction analysis of 9 of the responsive genes revealed a strong, positive correlation with RNA sequencing data. The genes were enriched in several pathways, including carbon metabolism pathway, plant-pathogen interaction pathway, and plant hormone signal transduction pathway. Differentially expressed genes (DEGs) encoding transcription factors associated with abiotic stress responses and salt stress response network were identified; their expression levels differed between the two samples in response to salt stress. Hub genes were also revealed by weighted gene co-expression network (WGCNA) analysis. For functional analysis of the DEG encoding sedoheptulose-1,7-bisphosphatase (SBPase), the gene was overexpressed in transgenic Arabidopsis, resulting in increased photosynthetic rates, sucrose and starch accumulation, and enhanced salt tolerance. Further functional characterization of other hub DEGs will reveal the molecular mechanism of salt tolerance in S. matsudana and allow the application of S. matsudana in coastal afforestation.


Assuntos
Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes/fisiologia , Salix/fisiologia , Tolerância ao Sal/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Fotossíntese/genética , Raízes de Plantas , Plantas Geneticamente Modificadas , RNA-Seq , Salinidade , Amido/metabolismo , Sacarose/metabolismo
2.
PLoS One ; 15(8): e0235355, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32817671

RESUMO

The Arbuscular mycorrhizal fungi (AMF) (Funneliformis mosseae), are the most widely distributed symbiont assisting plants to overcome counteractive environmental conditions. In order to improve the sustainability and the activity of AMF, the use of nanotechnology was important. The main objective of this study was to investigate the effect of titanium dioxide nanoparticles (TiO2NPs) on the activity of AMF in common bean roots as well as its activity under salinity stress using morphological and molecular methods. The activity of AMF colonization has increased in the presence of TiO2NPs especially for arbuscule activity (A%), which increased three times with the presence of TiO2NPs. The improvement rate of Funneliformis mosseae on plant growth increased from 180% to 224% of control at the lowest level of salinity and increased from 48% to 130% at higher salinity level, respectively. The AMF dependencies for plant dry biomass increased in the presence of TiO2NPs from 277% in the absence of salinity to 465 and 883% % at low and high salinity levels, respectively. The presence of AMF co-inoculated with TiO2NPs resulted in increasing the salinity tolerance of plants at all levels and reached 110% at salinity level of 100 mM NaCl. Quantitative colonization methods showed that the molecular intensity ratio and the relative density of paired inocula AMF Nest (NS) or chitin synthases gene (Chs) with TiO2NPs were higher significantly P.>0.05 than single inoculants of AMF gene in roots under the presence or the absence of salinity by about two folds and about 40%. Hence, the positive effect of TiO2NPs was confined to its effect on AMF not on bean plants itself.


Assuntos
Ascomicetos/patogenicidade , Nanopartículas Metálicas/química , Phaseolus/microbiologia , Tolerância ao Sal , Ascomicetos/efeitos dos fármacos , Ascomicetos/metabolismo , Quitina Sintase/genética , Quitina Sintase/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Nanopartículas Metálicas/microbiologia , Phaseolus/metabolismo , Simbiose , Titânio/química , Titânio/farmacologia
3.
Sheng Wu Gong Cheng Xue Bao ; 36(7): 1356-1364, 2020 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-32748593

RESUMO

Salinity is the most important factor for the growth of crops. It is an effective method to alleviate the toxic effect caused by salt stress using saline-alkali-tolerant and growth-promoting bacteria in agriculture. Seven salt-tolerant bacteria were screened from saline-alkali soil, and the abilities of EPS production, alkalinity reduction and IAA production of the selected strains were investigated. A dominant strain DB01 was evaluated. The abilities of EPS production, alkalinity reduction and IAA production of strain DB01 were 0.21 g/g, 8.7% and 8.97 mg/L, respectively. The isolate was identified as Halomonas aquamarina by partial sequencing analysis of its 16S rRNA genes, and had the ability to inhibit the growth of Fusarium oxysporum f. sp., Alternaria solani, Phytophthora sojae and Rhizoctonia cerealis. It also could promote root length and germination rate of wheat seedlings under salt stress. Halomonas aquamarina can provide theoretical basis for the development of soil microbial resources and the application in saline-alkali soil improvement.


Assuntos
Álcalis , Raízes de Plantas , Tolerância ao Sal , Microbiologia do Solo , Álcalis/metabolismo , Bactérias/efeitos dos fármacos , Bactérias/genética , Halomonas/genética , Raízes de Plantas/microbiologia , RNA Ribossômico 16S/genética , Tolerância ao Sal/genética , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Solo/química , Triticum/microbiologia
4.
PLoS One ; 15(7): e0236037, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32701981

RESUMO

Soil salinity imposes an agricultural and economic burden that may be alleviated by identifying the components of salinity tolerance in barley, a major crop and the most salt tolerant cereal. To improve our understanding of these components, we evaluated a diversity panel of 377 two-row spring barley cultivars during both the vegetative, in a controlled environment, and the reproductive stages, in the field. In the controlled environment, a high-throughput phenotyping platform was used to assess the growth-related traits under both control and saline conditions. In the field, the agronomic traits were measured from plots irrigated with either fresh or saline water. Association mapping for the different components of salinity tolerance enabled us to detect previously known associations, such as HvHKT1;5. Using an "interaction model", which took into account the interaction between treatment (control and salt) and genetic markers, we identified several loci associated with yield components related to salinity tolerance. We also observed that the two developmental stages did not share genetic regions associated with the components of salinity tolerance, suggesting that different mechanisms play distinct roles throughout the barley life cycle. Our association analysis revealed that genetically defined regions containing known flowering genes (Vrn-H3, Vrn-H1, and HvNAM-1) were responsive to salt stress. We identified a salt-responsive locus (7H, 128.35 cM) that was associated with grain number per ear, and suggest a gene encoding a vacuolar H+-translocating pyrophosphatase, HVP1, as a candidate. We also found a new QTL on chromosome 3H (139.22 cM), which was significant for ear number per plant, and a locus on chromosome 2H (141.87 cM), previously identified using a nested association mapping population, which associated with a yield component and interacted with salinity stress. Our study is the first to evaluate a barley diversity panel for salinity stress under both controlled and field conditions, allowing us to identify contributions from new components of salinity tolerance which could be used for marker-assisted selection when breeding for marginal and saline regions.


Assuntos
Cromossomos de Plantas , Hordeum/genética , Tolerância ao Sal/genética , Flores/genética , Flores/metabolismo , Genótipo , Hordeum/crescimento & desenvolvimento , Hordeum/metabolismo , Pirofosfatase Inorgânica/genética , Fenótipo , Proteínas de Plantas/genética , Locos de Características Quantitativas , Solo/química
5.
Gene ; 757: 144935, 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-32653482

RESUMO

MYB transcription factors (TFs) play important roles in the plant's response to abiotic stress. In this study, we cloned a novel MYB TF gene from Vaccinium corymbosum (blueberry) using rapid amplification of cDNA ends (RACE). The cDNA contained a 798-bp open reading frame that encodes a 265-amino acid protein. VcMYB4a possessed a C2/EAR-repressor motif domain and phylogenetic analysis showed that it clustered into a subgroup 4 with six Arabidopsis thaliana MYBs. Quantitative RT-PCR analysis demonstrated that VcMYB4a expression was downregulated by salt, drought, and cold treatment, but was induced by freezing and heat. Overexpression of VcMYB4a in blueberry callus enhanced sensitivity to salt, drought, cold, freezing, and heat stress. These results indicate that VcMYB4a may be an important repressor of abiotic stress in blueberry.


Assuntos
Mirtilos Azuis (Planta)/genética , Resposta ao Choque Térmico , Proteínas de Plantas/genética , Tolerância ao Sal , Termotolerância , Fatores de Transcrição/genética , Mirtilos Azuis (Planta)/metabolismo , Secas , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Domínios Proteicos , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo
6.
Plant Mol Biol ; 103(4-5): 545-560, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32504260

RESUMO

KEY MESSAGE: OsGTγ-2, a trihelix transcription factor, is a positive regulator of rice responses to salt stress by regulating the expression of ion transporters. Salinity stress seriously restricts rice growth and yield. Trihelix transcription factors (GT factors) specifically bind to GT elements and play a diverse role in plant morphological development and responses to abiotic stresses. In our previous study, we found that the GT-1 element (GAAAAA) is a key element in the salinity-induced OsRAV2 promoter. Here, we identified a rice OsGTγ family member, OsGTγ-2, which directly interacted with the GT-1 element in the OsRAV2 promoter. OsGTγ-2 specifically targeted the nucleus, was mainly expressed in roots, sheathes, stems and seeds, and was induced by salinity, osmotic and oxidative stresses and abscisic acid (ABA). The seed germination rate, seedling growth and survival rate under salinity stress was improved in OsGTγ-2 overexpressing lines (PZmUbi::OsGTγ-2). In contrast, CRISPR/Cas9-mediated OsGTγ-2 knockout lines (osgtγ-2) showed salt-hypersensitive phenotypes. In response to salt stress, different Na+ and K+ acclamation patterns were observed in PZmUbi::OsGTγ-2 lines and osgtγ-2 plants were observed. The molecular mechanism of OsGTγ-2 in rice salt adaptation was also investigated. Several major genes responsible for ion transporting, such as the OsHKT2; 1, OsHKT1; 3 and OsNHX1 were transcriptionally regulated by OsGTγ-2. A subsequent yeast one-hybrid assay and EMSA indicated that OsGTγ-2 directly interacted with the promoters of OsHKT2; 1, OsNHX1 and OsHKT1; 3. Taken together, these results suggest that OsGTγ-2 is an important positive regulator involved in rice responses to salt stress and suggest a potential role for OsGTγ-2 in regulating salinity adaptation in rice.


Assuntos
Aclimatação/fisiologia , Proteínas de Ligação a DNA/metabolismo , Oryza/fisiologia , Estresse Salino/fisiologia , Tolerância ao Sal/genética , Fatores de Transcrição/metabolismo , Ácido Abscísico/metabolismo , Aclimatação/genética , Adaptação Fisiológica , Sistemas CRISPR-Cas , Proteínas de Transporte de Cátions/metabolismo , Proteínas de Ligação a DNA/genética , Regulação da Expressão Gênica de Plantas , Oryza/genética , Oryza/crescimento & desenvolvimento , Desenvolvimento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Salinidade , Plântula/genética , Sementes/metabolismo , Sódio/metabolismo , Trocadores de Sódio-Hidrogênio/metabolismo , Estresse Fisiológico/genética , Simportadores/metabolismo , Fatores de Transcrição/genética
7.
Mycorrhiza ; 30(4): 419-429, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32363467

RESUMO

To examine the effects of ericoid mycorrhizal (ERM) fungi on salt tolerance of ericaceous plants, we inoculated roots of velvetleaf blueberry (Vaccinium myrtilloides), Labrador tea (Rhododendron groenlandicum), and lingonberry (Vaccinium vitis-idaea) with ericoid mycorrhizal fungi Oidiodendron maius and Meliniomyces variabilis. Plants were subjected to 0 (NaCl control) and 30 mM NaCl treatments, and plant dry weights, gas exchange, and leaf chlorophyll concentrations were compared in inoculated and non-inoculated plants. M. variabilis increased root dry weights in all three species of NaCl-treated plants, and O. maius enhanced root dry weights of lingonberry plants treated with NaCl. Both fungal species were especially effective in enhancing root and shoot dry weights in control (0 mM NaCl) and NaCl-treated lingonberry seedlings. Leaf chlorophyll concentrations were enhanced by fungal inoculation in all three plant species, and this effect persisted under salt stress in Labrador tea and lingonberry. Salt treatment drastically reduced transpiration rates (E) and lowered net photosynthesis (Pn) to the negative values in all three species of non-inoculated plants, and this effect was partly or almost completely reversed by the inoculation with O. maius and M. variabilis. Fungal inoculation was especially effective in reducing NaCl effects on Pn in lingonberry. Oidiodendron maius and M. variabilis were also equally effective in reversing NaCl-induced declines of E in velvetleaf blueberry and lingonberry. However, in Labrador tea, O. maius reversed the decline of E in NaCl-treated plants less compared with M. variabilis resulting in high photosynthetic water use efficiency values. The results support the hypothesis that, similarly to arbuscular mycorrhizal and ectomycorrhizal associations, ERM association increases salt tolerance of plants.


Assuntos
Ascomicetos , Micorrizas , Fungos , Raízes de Plantas , Plantas , Tolerância ao Sal
8.
Mycorrhiza ; 30(4): 431-444, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32367433

RESUMO

Soil salinization due to sea level rise and groundwater irrigation has become an important agronomic problem in many parts of the world. Symbiosis between crop species and arbuscular mycorrhizal fungi (AMF) may alleviate salt stress-induced detrimental effects on crop growth and yield, for example, through helping the host plant to selectively absorb potassium while avoiding uptake of excessive sodium. Here, we performed a greenhouse experiment to evaluate growth, grain yield, and salt tolerance of a Bangladeshi rice cultivar under three levels of salt stress (0, 75, and 120 mM) after inoculation with three different AMF species from three different genera (Funnelliformis mosseae (BEG12), Acaulospora laevis (BEG13), and Gigaspora margarita (BEG34)), singly and in combination. We found that under salt stress, AMF inoculation enhanced total chlorophyll concentration, shoot K+/Na+ ratio, and lowered shoot Na+/root Na+ ratio, accompanied by increased root biomass, spikelet fertility, and grain yield compared with the non-inoculated control plants. Specifically, we found that the combination of BEG13 and BEG34 increased rice yield by 125 and 143% as compared with the non-inoculated controls, at the 75 and 120mM salt levels, respectively. In general, the low AMF diversity treatments (one species or a combination of two AMF species) were found to be the most effective in mediating salt stress tolerance for the majority of the measured crop performance variables. Overall, our results indicate that specific AMF species can promote the salt tolerance and productivity of rice, likely by increasing photosynthetic efficiency and restricting Na+ uptake and transport from root to shoot in AMF-inoculated plants.


Assuntos
Micorrizas , Oryza , Biomassa , Raízes de Plantas , Tolerância ao Sal , Simbiose
9.
Plant Mol Biol ; 103(4-5): 561-580, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32405802

RESUMO

KEY MESSAGE: CmHKT1;1 selectively exports Na+ from plant cells. Upon NaCl stress, its expression increased in a salt-tolerant melon cultivar. Overexpression of CmHKT1;1 increased transgenic Arabidopsis salt tolerance through improved K+/Na+ balance. High-affinity K+ transporters (HKTs) are thought to be involved in reducing Na+ in plant shoots under salt stress and modulating salt tolerance, but their function in a moderately salt-tolerant species of melon (Cucumis melo L.) remains unclear. In this study, a Na+ transporter gene, CmHKT1;1 (GenBank accession number: MK986658), was isolated from melons based on genome data. The transcript of CmHKT1;1 was relatively more abundant in roots than in stems or leaves from melon seedlings. The tobacco transient expression system showed that CmHKT1;1 was plasma-membrane localized. Upon salt stress, CmHKT1;1 expression was more strongly upregulated in a salt-tolerant melon cultivar, 'Bingxuecui' (BXC) compared with a salt-sensitive cultivar, 'Yulu' (YL). Electrophysiological evidence demonstrated that CmHKT1;1 only transported Na+, rather than K+, when expressed in Xenopus laevis oocytes. Overexpression of CmHKT1;1 increased salt sensitivity in Saccharomyces cerevisiae and salt tolerance in Arabidopsis thaliana. Under NaCl treatments, transgenic Arabidopsis plants accumulated significantly lower concentrations of Na+ in shoots than wild type plants and showed a better K+/Na+ balance, leading to better Fv/Fm, root length, biomass, and enhanced plant growth. The CmHKT1;1 gene may serve as a useful candidate for improving crop salt tolerance.


Assuntos
Arabidopsis/metabolismo , Cucumis melo/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Potássio/metabolismo , Sódio/metabolismo , Arabidopsis/genética , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Clorofila/análise , Clonagem Molecular , Cucumis melo/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Membrana Transportadoras/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/metabolismo , Brotos de Planta/genética , Saccharomyces cerevisiae/genética , Tolerância ao Sal , Plântula/genética , Plântula/metabolismo , Alinhamento de Sequência , Análise de Sequência de Proteína , Cloreto de Sódio/metabolismo , Estresse Fisiológico/genética , Estresse Fisiológico/fisiologia , Simportadores/genética , Simportadores/metabolismo , Tabaco/genética , Tabaco/metabolismo
10.
PLoS One ; 15(5): e0233616, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32470066

RESUMO

Salt stress is a common abiotic stress that limits the growth, development and yield of maize (Zea mays L.). To better understand the response of maize to salt stress and the mechanism by which exogenous glycine betaine (GB) alleviates the damaging effects of salt stress, the morphology, physiological and biochemical indexes, and root transcriptome expression profiles of seedlings of salt-sensitive inbred line P138 and salt-tolerant inbred line 8723 were compared under salt stress and GB-alleviated salt stress conditions. The results showed that under salt stress the growth of P138 was significantly inhibited and the vivo ion balance was disrupted, whereas 8723 could prevent salt injury by maintaining a high ratio of K+ to Na+. The addition of a suitable concentration of GB could effectively alleviate the damage caused by salt stress, and the mitigating effect on salt-sensitive inbred line P138 was more obvious than that on 8723. Transcriptome analysis revealed that 219 differentially expressed genes (DEGs) were up-regulated and 153 DEGs were down-regulated in both P138 and 8723 under NaCl treatment, and that 487 DEGs were up-regulated and 942 DEGs were down-regulated in both P138 and 8723 under salt plus exogenous GB treatment. In 8723 the response to salt stress is mainly achieved through stabilizing ion homeostasis, strong signal transduction activation, increasing reactive oxygen scavenging. GB alleviates salt stress in maize mainly by inducing gene expression changes to enhance the ion balance, secondary metabolic level, reactive oxygen scavenging mechanism, signal transduction activation. In addition, the transcription factors involved in the regulation of salt stress response and exogenous GB mitigation mainly belong to the MYB, MYB-related, AP2-EREBP, bHLH, and NAC families. We verified 10 selected up-regulated DEGs by quantitative real-time polymerase chain reaction (qRT-PCR), and the expression results were basically consistent with the transcriptome expression profiles. Our results from this study may provide the theoretical basis for determining maize salt tolerance mechanisms and the mechanism by which GB regulates salt tolerance.


Assuntos
Betaína/metabolismo , Tolerância ao Sal , Plântula/genética , Transcriptoma , Zea mays/genética , Regulação da Expressão Gênica de Plantas , Potássio/metabolismo , Plântula/fisiologia , Sódio/metabolismo , Zea mays/fisiologia
11.
Gene ; 753: 144803, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32446917

RESUMO

R2R3-type MYBs are a key group of regulatory factors that control diverse developmental processes and stress tolerance in plants. Soybean is a major legume crop with the richness of seed protein and edible vegetable oil, and 244 R2R3-type MYBs have been identified in soybean. However, the knowledge regarding their functional roles has been greatly limited as yet. In this study, a novel R2R3-type MYB (GmMYB81) was functionally characterized in soybean, and it is closely related to two abiotic stress-associated regulators (AtMYB44 and AtMYB77). GmMYB81 transcripts not only differentially accumulated in soybean tissues and during embryo development, but also were significantly enhanced by drought, salt and cold stress. Histochemical GUS assay in Arabidopsis indicated that GmMYB81 promoter showed high activity in seedlings, rosette leaves, inflorescences, silique wall, mature anthers, roots, and germinating seeds. Further investigation indicated that over-expression of GmMYB81 in Arabidopsis caused auxin-associated phenotypes, including small flower and silique, more branch, and weakened apical dominance. Moreover, over-expression of GmMYB81 significantly elevated the rates of seed germination and green seedling under salt and drought stress, indicating that GmMYB81 might confer plant tolerance to salt and drought stress during seed germination. Additionally, protein interaction analysis showed that GmMYB81 interacts with the abiotic stress regulator GmSGF14l. Further observation indicated that they displayed similar expression patterns under drought and salt stress, suggesting GmMYB81 and GmSGF14l might cooperatively affect stress tolerance. These findings will facilitate future investigations of the regulatory mechanisms of GmMYB81 in response to plant stress tolerance, especially seed germination under abiotic stresses.


Assuntos
Proteínas de Arabidopsis/genética , Soja/genética , Estresse Fisiológico/genética , Fatores de Transcrição/genética , Ácido Abscísico/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Secas , Fabaceae/genética , Flores/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Genes de Plantas/genética , Germinação/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Estresse Salino/genética , Tolerância ao Sal/genética , Sementes/metabolismo , Fatores de Transcrição/metabolismo
12.
Gene ; 753: 144802, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32454178

RESUMO

Synchronous and timely regulation of multiple genes results in an effective defense response that decides the fate of the host when challenged with pathogens or unexpected changes in environmental conditions. One such gene, which is downregulated in response to multiple bacterial pathogens, is a putative nonspecific lipid transfer protein (nsLTP) of unknown function that we have named DISEASE RELATED NONSPECIFIC LIPID TRANSFER PROTEIN 1 (DRN1). We show that upon pathogen challenge, DRN1 is strongly downregulated, while a putative DRN1-targeting novel microRNA (miRNA) named DRN1 Regulating miRNA (DmiR) is reciprocally upregulated. Furthermore, we provide evidence that DRN1 is required for defense against bacterial and fungal pathogens as well as for normal seedling growth under salinity stress. Although nsLTP family members from different plant species are known to be a significant source of food allergens and are often associated with antimicrobial properties, our knowledge on the biological functions and regulation of this gene family is limited. Our current work not only sheds light on the mechanism of regulation but also helps in the functional characterization of DRN1, a putative nsLTP family member of hitherto unknown function.


Assuntos
Arabidopsis/genética , Proteínas de Transferência de Fosfolipídeos/genética , Estresse Salino/genética , Ácido Abscísico/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Resistência à Doença/genética , Secas , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Proteínas de Transferência de Fosfolipídeos/metabolismo , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Patologia Vegetal , Plantas Geneticamente Modificadas , Salinidade , Tolerância ao Sal/genética , Plântula/genética , Estresse Fisiológico/genética
13.
Ecotoxicol Environ Saf ; 200: 110732, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32460049

RESUMO

This paper reports the role of exogenous glycine betaine (25 and 50 mM GB at a rate of 50 mL per plant) in enhancing NaCl-stress tolerance in common bean (Phaseolus vulgaris L.). Irrigating plants by simulated saline water, containing 0, 50 and 100 mM sodium chloride (NaCl), significantly reduced the growth dynamics, photosynthetic pigments (i.e., Chl a, Chl b, and carotenoids), membrane stability index (MSI), relative water content (RWC), and pod yield. While, malondialdehyde (MDA), endogenous proline, and glutathione contents, electrolyte leakage (EL), antioxidant defense system, and Na+ accumulation markedly increased upon exposure to NaCl-stress. However, the application of exogenous GB significantly improved salt tolerance of common bean as it increased the antioxidant defense including both enzymatic (i.e., peroxidase, superoxide dismutase, and catalase) and nonenzymatic (i.e., proline and glutathione) agents. Consequently, MSI, RWC, EL, and photosynthetic pigments have been improved recording significantly higher values than the control. Moreover, the pod yield increased by 29.8 and 59.4% when plants grown under 50 and 100 mM NaCl, respectively, were sprayed with 25 mM GB. Our results show that GB-induced slat tolerance in common bean plants mainly depends on the osmoregulation effect of GB and to a lesser extent on its antioxidant capacity. Foliar application of GB significantly reduced the accumulation of Na+ and at the same time induced K+ uptake maintaining a higher K+/Na+ ratio. Despite some changes in the activities of antioxidant enzymes induced by the application of GB, no consistent contribution in the salt tolerance could be cited in this study. Therefore, we suggest that salt tolerance is largely unrelated to the antioxidant defense ability of GB in common bean. While the potential role of GB in ameliorating salt tolerance is mainly due to the adjustment of ions uptake through limiting Na+ uptake and alternatively increasing K+ accumulation in plant tissues.


Assuntos
Betaína/farmacologia , Phaseolus/efeitos dos fármacos , Potássio/metabolismo , Tolerância ao Sal , Sódio/metabolismo , Antioxidantes/metabolismo , Transporte Biológico/efeitos dos fármacos , Catalase/metabolismo , Cátions , Glutationa/metabolismo , Malondialdeído/análise , Osmorregulação/efeitos dos fármacos , Peroxidase/metabolismo , Phaseolus/química , Phaseolus/enzimologia , Phaseolus/metabolismo , Fotossíntese/efeitos dos fármacos , Potássio/análise , Prolina/metabolismo , Sódio/análise , Superóxido Dismutase/metabolismo
14.
PLoS One ; 15(4): e0231348, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32298338

RESUMO

Salt stress is one of the devastating factors that hampers growth and productivity of soybean. Use of Pseudomonas pseudoalcaligenes to improve salt tolerance in soybean has not been thoroughly explored yet. Therefore, we observed the response of hydroponically grown soybean plants, inoculated with halotolerant P. pseudoalcaligenes (SRM-16) and Bacillus subtilis (SRM-3) under salt stress. In vitro testing of 44 bacterial isolates revealed that four isolates showed high salt tolerance. Among them, B. subtilis and P. pseudoalcaligenes showed ACC deaminase activity, siderophore and indole acetic acid (IAA) production and were selected for the current study. We determined that 106 cells/mL of B. subtilis and P. pseudoalcaligenes was sufficient to induce tolerance in soybean against salinity stress (100 mM NaCl) in hydroponics by enhancing plant biomass, relative water content and osmolytes. Upon exposure of salinity stress, P. pseudoalcaligenes inoculated soybean plants showed tolerance by the increased activities of defense related system such as ion transport, antioxidant enzymes, proline and MDA content in shoots and roots. The Na+ concentration in the soybean plants was increased in the salt stress; while, bacterial priming significantly reduced the Na+ concentration in the salt stressed soybean plants. However, the antagonistic results were observed for K+ concentration. Additionally, soybean primed with P. pseudoalcaligenes and exposed to 100 mM NaCl showed a new protein band of 28 kDa suggesting that P. pseudoalcaligenes effectively reduced salt stress. Our results showed that salinity tolerance was more pronounced in P. pseudoalcaligenes as compared to B. subtilis. However, a detailed study at molecular level to interpret the mechanism by which P. pseudoalcaligenes alleviates salt stress in soybean plants need to be explored.


Assuntos
Bacillus subtilis/patogenicidade , Pseudomonas pseudoalcaligenes/patogenicidade , Tolerância ao Sal , Soja/metabolismo , Bacillus subtilis/metabolismo , Transporte de Íons , Malondialdeído/metabolismo , Peroxidase/genética , Peroxidase/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Prolina/metabolismo , Pseudomonas pseudoalcaligenes/metabolismo , Espécies Reativas de Oxigênio , Soja/microbiologia
15.
Pestic Biochem Physiol ; 164: 149-155, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32284121

RESUMO

Productivity of safflower (Carthamus tinctorius L.) is markedly reduced by salt stress. This study is based on analysis of proteins profile of safflower plants treated with 200 mM NaCl, with exogenously applied salicylic acid (SA) and penconazole (PEN), as growth regulators. Plants were investigated through a gel-based proteomic approach, which resulted in the identification of 17 salt-responsive proteins related to different metabolic modifications. Of these, seven different proteins were up or down regulated by both SA and PEN, suggesting the synergistic and antagonistic effects of SA and PEN. The classification of differentially expressed proteins showed that salt-responsive proteins were mainly involved in photosynthesis, ion homeostasis, and oxidative stress response, as well as nitrogen, protein, and carbohydrate metabolism. The identified stress-responsive proteins in this study could pave the way to develop salt tolerance in safflower, thus sustaining its productivity under salinity. In addition, SA and PEN may be considered as a foliar application to ameliorate salinity effects, due to their low price and availability.


Assuntos
Carthamus tinctorius , Plântula , Proteínas de Plantas , Proteômica , Salinidade , Tolerância ao Sal , Estresse Fisiológico
16.
Artigo em Inglês | MEDLINE | ID: mdl-32224382

RESUMO

Osmotic stresses caused by reduced water availability or the accumulation of salts in the soil can be highly damaging to plants. The objective of this study was to investigate physiological responses and tolerance mechanisms of two turfgrass species (seashore paspalum and centipedegrass) with distinct differences in salinity tolerance exposed to osmotic and iso-osmotic salt stresses. Three turfgrass genotypes including seashore paspalums 'Seastar' and 'UGP113', and centipedegrass 'TifBlair' were grown in ½ strength Hoagland's solution with three different treatment conditions; control (no external addition), salt stress (-0.4 MPa by adding NaCl) and osmotic stress [-0.4 MPa by adding polyethylene glycol (PEG)]. Osmotic stress damages were more severe with greater reductions in turf quality, photochemical efficiency (Fv/Fm), relative water content (RWC) and leaf water potential (Ψw) compared to iso-osmotic salt stress in both seashore paspalum and centipedegrass. Greater osmotic adjustment (OA) with greater accumulation of metabolically inexpensive inorganic osmolytes (Na+) helped turfgrasses to lessen damages in salt stress compared to osmotic stress. However, such accumulation of Na+ resulted ion-toxicity and triggered some damages in terms of increased electrolyte leakage (EL) and reduced total protein in salt-sensitive centipedegrass. Seashore paspalum had better ion regulation and also maintained greater antioxidant enzyme activities compared to centipedegrass; therefore it was able to avoid ion-specific damages under salt stress. Differences in the utilization of specific solutes for osmotic adjustment and antioxidant metabolism are partially responsible for the differences in salt versus osmotic stress responses in these species; the regulation of these defense mechanisms requires further investigation.


Assuntos
Pressão Osmótica , Poaceae/fisiologia , Estresse Salino , Tolerância ao Sal , Genótipo , Paspalum/crescimento & desenvolvimento , Paspalum/fisiologia , Poaceae/genética
17.
Artigo em Inglês | MEDLINE | ID: mdl-32240936

RESUMO

Salt is a major abiotic stress that negatively impacts plant growth and development. Research on the mechanisms of plant salt tolerance and the breeding of salt-tolerant plants is becoming an important research field. Transcription factors are master regulators that control the expression of many target genes, helping to regulate the response of plants to adverse conditions. GRAS are plant-specific transcription factors that play various roles in plant development and stress responses. However, the function of a GRAS gene identified in Halostachys caspica, a salt-tolerant plant with important ecological value, has not been determined. In this study, we characterized a novel gene (HcSCL13) encoding a GRAS transcription factor from H. caspica. Quantitative real-time (qRT)-PCR results indicated that HcSCL13 expression was induced by salt, drought and application of stress-related phytohormone abscisic acid (ABA). The HcSCL13 protein was localized in the nucleus with transactivation activity at the N terminus. Heterologous overexpression of HcSCL13 enhanced plant growth and salt tolerance in transgenic Arabidopsis. With HcSCL13 overexpression, plants had enhanced growth, as well as greater chlorophyll content, fresh weight and root elongation compared to the wild type. Transcriptomic analysis revealed that HcSCL13 overexpression affected the response to light/abiotic stimulus/hormone/organic substance, plant hormone signal-related and plant growth and development genes under normal and saline stress conditions. Taken together, these results indicate that HcSCL13 genes can modulate salt stress tolerance in Arabidopsis through the regulation of plant growth and the activation of gene expression.


Assuntos
Arabidopsis , Chenopodiaceae , Expressão Gênica , Desenvolvimento Vegetal , Plantas Geneticamente Modificadas , Tolerância ao Sal , Fatores de Transcrição , Arabidopsis/genética , Chenopodiaceae/genética , Desenvolvimento Vegetal/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Tolerância ao Sal/genética , Fatores de Transcrição/genética
18.
Artigo em Inglês | MEDLINE | ID: mdl-32251957

RESUMO

Soil salinity of fields is often non-uniform. To obtain a better understanding of molecular response to non-uniform salt stress, we conducted transcriptomic analysis on the leaves and roots of alfalfa grown under 0/0, 200/200, and 0/200 mM NaCl treatments. A total of 233,742 unigenes were obtained from the assembled cDNA libraries. There were 98 and 710 unigenes identified as significantly differentially expressed genes (DEGs) in the leaves of non-uniform and uniform salt treatment, respectively. Furthermore, there were 5178 DEGs in the roots under uniform salt stress, 273 DEGs in the non-saline side and 4616 in the high-saline side roots under non-uniform salt stress. Alfalfa treated with non-uniform salinity had greater dry weight and less salt damage compared to treatment with uniform salinity. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the DEGs in roots revealed that both sides of the non-uniform salinity were enriched in pathways related to "phenylpropanoid biosynthesis" and "linoleic acid metabolism"; and "MAPK signaling pathway-plant" was also indicated as a key pathway in the high-saline roots. We also combined a set of important salt-response genes and found that roots from the non-saline side developed more roots with increased water uptake by altering the expression of aquaporins and genes related to growth regulation. Moreover, the hormone signal transduction and the antioxidant pathway probably play important roles in inducing more salt-related genes and increasing resistance to non-uniform salt stress on both sides of the roots.


Assuntos
Medicago sativa , Tolerância ao Sal , Transcriptoma , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Medicago sativa/genética , Medicago sativa/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Salinidade , Estresse Salino/genética , Tolerância ao Sal/genética
19.
Tree Physiol ; 40(9): 1292-1311, 2020 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-32334430

RESUMO

ZINC FINGER OF ARABIDOPSIS THALIANA12 (ZAT12) plays an important role in stress responses, but the transcriptional regulation of ZAT12 in response to abiotic stress remains unclear. In this study, we confirmed that a SALT TOLERANCE ZINC FINGER1 transcription factor from Populus euphratica (PeSTZ1) could regulate the expression of PeZAT12 by dual-luciferase reporter (DLR) assay and electrophoretic mobility shift assay. The expression of PeSTZ1 was rapidly induced by NaCl and hydrogen peroxide (H2O2) treatments. Overexpressing PeSTZ1 in poplar 84K (Populus alba × Populus glandulosa) plant was endowed with a strong tolerance to salt stress. Under salt stress, transgenic poplar exhibited higher expression levels of PeZAT12 and accumulated a larger amount of antioxidant than the wild-type plants. Meanwhile, ASCORBATE PEROXIDASE2 (PeAPX2) can be activated by PeZAT12 and PeSTZ1, promoting the accumulation of cytosolic ascorbate peroxidase (APX) to scavenge reactive oxygen species (ROS) under salt stress. This new regulatory model (PeSTZ1-PeZAT12-PeAPX2) was found in poplar, providing a new idea and insight for the interpretation of poplar resistance. Transgenic poplar reduced the accumulation of ROS, restrained the degradation of chlorophyll and guaranteed the photosynthesis and electron transport system. On the other hand, transgenic poplar slickly adjusted K+/Na+ homeostasis to alleviate salt toxicity in photosynthetic organs of plants under salt stress and then increased biomass accumulation. In summary, PeSTZ1 confers salt stress tolerance by scavenging the accumulation of ROS through regulating the expression of PeZAT12 and PeAPX2 in poplar.


Assuntos
Populus/genética , Regulação da Expressão Gênica de Plantas , Peróxido de Hidrogênio , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Espécies Reativas de Oxigênio , Estresse Salino , Tolerância ao Sal/genética , Estresse Fisiológico
20.
Artigo em Inglês | MEDLINE | ID: mdl-32291617

RESUMO

Salt tolerance and the possible functions of suberization on salt exclusion and secretion were examined in a dominant mangrove plant, Avicennia marina. The results showed that low salinities (10‰ and 20‰) almost has no negative effect on A. marina, however significant growth inhibitions were observed in the seedlings grown in higher salinities (30‰ and 40‰). With the increases of salinity, increased tissue Na+ content and enhanced salt secretion by glands were observed. Obvious suberization thickening were detected both in the exodermis and endodermis of the roots after salt pretreatment when compared to the roots without salt treatment. More importantly, the present data further confirmed that these root apoplastic barriers would directly decrease Na+ loading into xylem. Higher salt tolerance was observed in the seedlings pre-cultivated by salty tide when compared to fresh water cultivated A. marina. In summary, this study suggests a barrier property of suberization in dealing with salt exclusion in mangroves, a moderate salt pre-treatment may benefit plant withstanding high salinity.


Assuntos
Avicennia/fisiologia , Tolerância ao Sal/fisiologia , Íons , Raízes de Plantas , Salinidade , Plântula , Sódio , Xilema
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