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1.
J Microbiol ; 57(9): 717-724, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31452042

RESUMO

Salterns are hypersaline extreme environments with unique physicochemical properties such as a salinity gradient. Although the investigation of microbiota in salterns has focused on archaea and bacteria, diverse fungi also thrive in the brine and soil of salterns. Fungi isolated from salterns are represented by black yeasts (Hortaea werneckii, Phaeotheca triangularis, Aureobasidium pullulans, and Trimmatostroma salinum), Cladosporium, Aspergillus, and Penicillium species. Most studies on saltern-derived fungi gave attention to black yeasts and their physiological characteristics, including growth under various culture conditions. Since then, biochemical and molecular tools have been employed to explore adaptation of these fungi to salt stress. Genome databases of several fungi in salterns are now publicly available and being used to elucidate salt tolerance mechanisms and discover the target genes for agricultural and industrial applications. Notably, the number of enzymes and novel metabolites known to be produced by diverse saltern-derived fungi has increased significantly. Therefore, fungi in salterns are not only interesting and important subjects to study fungal biodiversity and adaptive mechanisms in extreme environments, but also valuable bioresources with potential for biotechnological applications.


Assuntos
Fungos/fisiologia , Sais/química , Cloreto de Sódio/metabolismo , Solo/química , Adaptação Fisiológica , Fungos/classificação , Fungos/genética , Fungos/isolamento & purificação , Tolerância ao Sal
2.
Gene ; 713: 143976, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31306715

RESUMO

Naturally evolved saline tolerant rice landraces found along the coastline of India are a valuable genomic resource to explore the complex, polygenic nature of salinity tolerance. In the present study, a set of 28 genome wide SSR markers, 11 salt responsive genic SSR markers and 8 Saltol QTL linked SSR markers were used to estimate genetic relatedness and population structure within a collection of 47 rice landraces (including a tolerant and 2 sensitive checks) originating from geographically divergent coastal regions of India. All three marker types identified substantial genetic variation among the landraces, as evident from their higher PIC values (0.53 for genomic SSRs, 0.43 for Genic SSRs and 0.59 for Saltol SSRs). The markers RM431, RM484 (Genomic SSRs), OsCAX (D), OsCAX (T) (Genic SSRs) and RM562 (Saltol SSR) were identified as good candidates to be used in breeding programs for improving salinity tolerance in rice. STRUCTURE analysis divided the landraces into five distinct populations, with classification correlating with their geographical locations. Principal coordinate and hierarchical cluster analyses (UPGMA and neighbor joining) are in close agreement with STRUCTURE results. AMOVA analysis indicated a higher magnitude of genetic differentiation within individuals of groups (58%), than among groups (42%). We also report the development and validation of a new Cleavage Amplified Polymorphic Sequence (CAPS) marker (OsHKT1;5V395) that targets a codon in the sodium transporter gene OsHKT1;5 (Saltol/SKC1 locus) that is associated with sodium transport rates in the above rice landraces. The CAPS marker was found to be present in all landraces except in IR29, Kamini, Gheus, Matla 1 and Matla 2. Significant molecular genetic diversity established among the analyzed salt tolerant rice landraces will aid in future association mapping; the CAPS marker, OsHKT1;5V395 can be used to map rice landraces for the presence of the SNP (Single Nucleotide Polymorphism) associated with increased sodium transport rates and concomitant salinity tolerance in rice.


Assuntos
Marcadores Genéticos , Variação Genética , Repetições de Microssatélites , Oryza/genética , Proteínas de Plantas/genética , Tolerância ao Sal/genética , Sódio/metabolismo , Genótipo , Filogenia
3.
Plant Mol Biol ; 101(1-2): 203-220, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31297725

RESUMO

KEY MESSAGE: Here, a functional characterization of a wheat MSR has been presented: this protein makes a contribution to the plant's tolerance of abiotic stress, acting through its catalytic capacity and its modulation of ROS and ABA pathways. The molecular mechanism and function of certain members of the methionine sulfoxide reductase (MSR) gene family have been defined, however, these analyses have not included the wheat equivalents. The wheat MSR gene TaMSRA4.1 is inducible by salinity and drought stress and in this study, we demonstrate that its activity is restricted to the Met-S-SO enantiomer, and its subcellular localization is in the chloroplast. Furthermore, constitutive expression of TaMSRA4.1 enhanced the salinity and drought tolerance of wheat and Arabidopsis thaliana. In these plants constitutively expressing TaMSRA4.1, the accumulation of reactive oxygen species (ROS) was found to be influenced through the modulation of genes encoding proteins involved in ROS signaling, generation and scavenging, while the level of endogenous abscisic acid (ABA), and the sensitivity of stomatal guard cells to exogenous ABA, was increased. A yeast two-hybrid screen, bimolecular fluorescence complementation and co-immunoprecipitation assays demonstrated that heme oxygenase 1 (HO1) interacted with TaMSRA4.1, and that this interaction depended on a TaHO1 C-terminal domain. In plants subjected to salinity or drought stress, TaMSRA4.1 reversed the oxidation of TaHO1, activating ROS and ABA signaling pathways, but not in the absence of HO1. The aforementioned properties advocate TaMSRA4.1 as a candidate for plant genetic enhancement.


Assuntos
Heme Oxigenase-1/metabolismo , Metionina Sulfóxido Redutases/metabolismo , Transdução de Sinais , Estresse Fisiológico , Triticum/enzimologia , Ácido Abscísico/metabolismo , Arabidopsis/enzimologia , Arabidopsis/genética , Arabidopsis/fisiologia , Secas , Perfilação da Expressão Gênica , Heme Oxigenase-1/genética , Metionina Sulfóxido Redutases/genética , Oxirredução , Reguladores de Crescimento de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Salinidade , Tolerância ao Sal , Plântula/enzimologia , Plântula/genética , Plântula/fisiologia , Triticum/genética , Triticum/fisiologia , Técnicas do Sistema de Duplo-Híbrido
4.
Plant Sci ; 286: 28-36, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31300139

RESUMO

MYB family genes act as important regulators modulating the response to abiotic stress in plants. However, much less is known about MYB proteins in cotton. Here, we found that a cotton MYB gene, GhMYB73, was induced by NaCl and abscisic acid (ABA). Silencing GhMYB73 expression in cotton increased sensitivity to salt stress. The cotyledon greening rate of Arabidopsis thaliana over-expressing GhMYB73 under NaCl or mannitol treatment was significantly enhanced during the seedling germination stage. What's more, several osmotic stress-induced genes, such as AtNHX1, AtSOS3 and AtP5CS1, were more highly induced in the over-expression lines than in wild type under salt treatment, supporting the hypothesis that GhMYB73 contributes to salinity tolerance by improving osmotic stress resistance. Arabidopsis lines over-expressing GhMYB73 had superior germination and cotyledon greening under ABA treatment, and some abiotic stress-induced genes involved in ABA pathways (AtPYL8, AtABF3, AtRD29B and AtABI5), had increased transcription levels under salt-stress conditions in these lines. Furthermore, we found that GhMYB73 physically interacts with GhPYL8 and AtPYL8, suggesting that GhMYB73 regulates ABA signaling during salinity stress response. Taken together, over-expression of GhMYB73 significantly increases tolerance to salt and ABA stress, indicating that it can potentially be used in transgenic technology approaches to improve cotton salt tolerance.


Assuntos
Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Gossypium/fisiologia , Proteínas de Plantas/genética , Estresse Salino/genética , Fatores de Transcrição/genética , Arabidopsis/genética , Inativação Gênica , Genes myb , Gossypium/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Tolerância ao Sal/genética , Fatores de Transcrição/metabolismo
5.
Physiol Plant ; 167(1): 2-4, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31268563

RESUMO

Generating salt-tolerant plants that can cope with increasing soil salinity is a major goal of crop-breeding programs worldwide. Together with genetic approaches, research efforts are focusing on finding chemical modulators of salt tolerance. The exogenous application of 5-aminolevulinic acid (ALA) has been shown to improve salt tolerance in diverse crop species, but its mechanism of action is not properly understood. Wu et al. (2019) report that ALA treatment enhances reactive oxygen species (ROS) production in the roots of salt-stressed strawberry plants. Activation of several key ion transporters downstream to the ROS signal helps to sequester the toxic Na+ ions in the roots and protects the shoots against salt stress.


Assuntos
Ácido Aminolevulínico/metabolismo , Fragaria/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fragaria/efeitos dos fármacos , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Tolerância ao Sal , Plantas Tolerantes a Sal/efeitos dos fármacos , Plantas Tolerantes a Sal/metabolismo , Cloreto de Sódio/farmacologia
6.
BMC Plant Biol ; 19(1): 300, 2019 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-31288738

RESUMO

BACKGROUND: Salinity is a major abiotic stress that limits the growth, productivity, and geographical distribution of plants. A comparative proteomics and gene expression analysis was performed to better understand salinity tolerance mechanisms in chickpea. RESULTS: Ten days of NaCl treatments resulted in the differential expression of 364 reproducible spots in seedlings of two contrasting chickpea genotypes, Flip 97-43c (salt tolerant, T1) and Flip 97-196c (salt susceptible, S1). Notably, after 3 days of salinity, 80% of the identified proteins in T1 were upregulated, while only 41% in S2 had higher expression than the controls. The proteins were classified into eight functional categories, and three groups of co-expression profile. The second co-expressed group of proteins had higher and/or stable expression in T1, relative to S2, suggesting coordinated regulation and the importance of some processes involved in salinity acclimation. This group was mainly enriched in proteins associated with photosynthesis (39%; viz. chlorophyll a-b binding protein, oxygen-evolving enhancer protein, ATP synthase, RuBisCO subunits, carbonic anhydrase, and fructose-bisphosphate aldolase), stress responsiveness (21%; viz. heat shock 70 kDa protein, 20 kDa chaperonin, LEA-2 and ascorbate peroxidase), and protein synthesis and degradation (14%; viz. zinc metalloprotease FTSH 2 and elongation factor Tu). Thus, the levels and/or early and late responses in the activation of targeted proteins explained the variation in salinity tolerance between genotypes. Furthermore, T1 recorded more correlations between the targeted transcripts and their corresponding protein expression profiles than S2. CONCLUSIONS: This study provides insight into the proteomic basis of a salt-tolerance mechanism in chickpea, and offers unexpected and poorly understood molecular resources as reliable starting points for further dissection.


Assuntos
Cicer/fisiologia , Proteínas de Plantas/metabolismo , Proteômica , Cicer/genética , Regulação da Expressão Gênica de Plantas , Genótipo , Fotossíntese , Proteínas de Plantas/genética , Salinidade , Tolerância ao Sal , Plântula/genética , Plântula/fisiologia , Estresse Fisiológico
7.
Gene ; 710: 279-290, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31200083

RESUMO

Plants are frequently exposed to variable environmental stresses that adversely affect plant growth, development and agricultural production. In this study, a trypanothione synthetase gene from Trypanosoma cruzi, TcTryS, was chemically synthesized and its roles in tolerance to multiple abiotic stresses were functionally characterized by generating transgenic rice overexpressing TcTryS. Overexpression of TcTryS in rice endows transgenic plants with hypersensitivity to ABA, hyposensitivity to NaCl- and mannitol-induced osmotic stress at the seed germination stage. TcTryS overexpression results in enhanced tolerance to drought, salt, cadmium, and 2,4,6-trichlorophenol stresses in transgenic rice, simultaneously supported by improved physiological traits. The TcTryS-overexpression plants also accumulated greater amounts of proline, less malondialdehyde and more transcripts of stress-related genes than wild-type plants under drought and salt stress conditions. In addition, TcTryS might play a positive role in maintaining chlorophyll content under 2,4,6-trichlorophenol stress. Histochemical staining assay showed that TcTryS renders transgenic plants better ROS-scavenging capability. All of these results suggest that TcTryS could function as a key regulator in modulation of abiotic stress tolerance in plant, and may have applications in the engineering of economically important crops.


Assuntos
Amida Sintases/genética , Amida Sintases/metabolismo , Oryza/genética , Estresse Fisiológico , Trypanosoma cruzi/enzimologia , Ácido Abscísico/farmacologia , Cádmio/toxicidade , Secas , Regulação da Expressão Gênica de Plantas , Oryza/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Tolerância ao Sal , Trypanosoma cruzi/genética , Regulação para Cima
8.
Microbiol Res ; 223-225: 33-43, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31178049

RESUMO

Mangroves, dominating tropical intertidal zones and estuaries, are among the most salt tolerant plants, and propagate through reproductive units called propagules. Similarly to plant seeds, propagules may harbor beneficial bacteria. Our hypothesis was that mangroves, being able to grow into seawater, should harbor bacteria able to interact with the host and to exert positive effects under salt stress, which could be exploited to improve crop production. Therefore, we isolated bacterial endophytes from mangrove propagules with the aim to test whether these bacteria have a beneficial potential on their natural host and on different crops such as barley and rice, cultivated under salt stress. The 172 bacterial isolates obtained were screened for plant growth promotion (PGP) activities in vitro, and the 12 most promising isolates were tested on barley under non-axenic conditions and salt stress. Gordonia terrae KMP456-M40 was the best performing isolate, increasing ear weight by 65%. Based on the in vivo PGP activity and the root colonization ability, investigated by fluorescence in situ hybridization and confocal microscopy, three strains were additionally tested on mangrove propagule germination and on rice growth. The most effective strain was again G. terrae KMP456-M40, which enhanced the root length of mangrove seedlings and the biomass of salt-stressed rice under axenic conditions up to 65% and 62%, respectively. We demonstrated that propagules, the reproductive units of mangroves, host beneficial bacteria that enhance the potential of mangrove seedlings establishment and confer salt tolerance to cereal crops.


Assuntos
Produtos Agrícolas , Grão Comestível/crescimento & desenvolvimento , Endófitos/fisiologia , Desenvolvimento Vegetal , Estresse Salino , Bactérias/classificação , Bactérias/isolamento & purificação , Biomassa , Endófitos/classificação , Endófitos/crescimento & desenvolvimento , Endófitos/isolamento & purificação , Genótipo , Germinação , Hordeum/crescimento & desenvolvimento , Hordeum/microbiologia , Hibridização in Situ Fluorescente , Oryza/microbiologia , Pressão Osmótica , Raízes de Plantas/microbiologia , Salinidade , Tolerância ao Sal , Plantas Tolerantes a Sal/microbiologia , Arábia Saudita , Água do Mar , Plântula/crescimento & desenvolvimento , Plântula/microbiologia , Sementes/crescimento & desenvolvimento , Sementes/microbiologia , Microbiologia do Solo , Áreas Alagadas
9.
J Plant Physiol ; 239: 38-51, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31181407

RESUMO

Reaumuria trigyna (Reaumuria Linn genus, family Tamaricaceae), an endangered dicotyledonous shrub with the features of a recretohalophyte, is endemic to the Eastern Alxa-Western Ordos area of China. Based on R. trigyna transcriptome data and expression pattern analysis of RtWRKYs, RtWRKY23, a Group II WRKY transcription factor, was isolated from R. trigyna cDNA. RtWRKY23 was mainly expressed in the stem and was induced by salt, drought, cold, ultraviolet radiation, and ABA treatments, but suppressed by heat treatment. Overexpression of RtWRKY23 in Arabidopsis increased chlorophyll content, root length, and fresh weight of the transgenic lines under salt stress. Real-time quantitative PCR (qPCR) analysis and yeast one-hybrid analysis demonstrated that RtWRKY23 protein directly or indirectly modulated the expression levels of downstream genes, including stress-related genes AtPOD, AtPOD22, AtPOD23, AtP5CS1, AtP5CS2, and AtPRODH2, and reproductive development-related genes AtMAF5, AtHAT1, and AtANT. RtWRKY23 transgenic Arabidopsis had higher proline content, peroxidase activity, and superoxide anion clearance rate, and lower H2O2 and malondialdehyde content than WT plants under salt stress conditions. Moreover, RtWRKY23 transgenic Arabidopsis exhibited later flowering and shorter pods, but little change in seed yield, compared with WT plants under salt stress. Our study demonstrated that RtWRKY23 not only enhanced salt stress tolerance through maintaining the ROS and osmotic balances in plants, but also participated in the regulation of flowering under salt stress.


Assuntos
Flores/crescimento & desenvolvimento , Proteínas de Plantas/genética , Tolerância ao Sal/genética , Tamaricaceae/fisiologia , Fatores de Transcrição/genética , Sequência de Aminoácidos , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Alinhamento de Sequência , Tamaricaceae/genética , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo
10.
J Microbiol Biotechnol ; 29(7): 1124-1136, 2019 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-31216607

RESUMO

Salinity is one of the major abiotic stresses that cause reduction of plant growth and crop productivity. It has been reported that plant growth-promoting bacteria (PGPB) could confer abiotic stress tolerance to plants. In a previous study, we screened bacterial strains capable of enhancing plant health under abiotic stresses and identified these strains based on 16s rRNA sequencing analysis. In this study, we investigated the effects of two selected strains, Bacillus aryabhattai H19-1 and B. mesonae H20-5, on responses of tomato plants against salinity stress. As a result, they alleviated decrease in plant growth and chlorophyll content; only strain H19-1 increased carotenoid content compared to that in untreated plants under salinity stress. Strains H19-1 and H20-5 significantly decreased electrolyte leakage, whereas they increased Ca2+ content compared to that in the untreated control. Our results also indicated that H20-5-treated plants accumulated significantly higher levels of proline, abscisic acid (ABA), and antioxidant enzyme activities compared to untreated and H19-1-treated plants during salinity stress. Moreover, strain H20-5 upregulated 9-cisepoxycarotenoid dioxygenase 1 (NCED1) and abscisic acid-response element-binding proteins 1 (AREB1) genes, otherwise strain H19-1 downregulated AREB1 in tomato plants after the salinity challenge. These findings demonstrated that strains H19-1 and H20-5 induced ABA-independent and -dependent salinity tolerance, respectively, in tomato plants, therefore these strains can be used as effective bio-fertilizers for sustainable agriculture.


Assuntos
Bacillus/fisiologia , Lycopersicon esculentum/fisiologia , Reguladores de Crescimento de Planta/farmacologia , Tolerância ao Sal/efeitos dos fármacos , Ácido Abscísico/metabolismo , Antioxidantes/metabolismo , Clorofila/metabolismo , Fertilizantes , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Lycopersicon esculentum/crescimento & desenvolvimento , Lycopersicon esculentum/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Proteínas de Plantas/genética , Prolina/metabolismo , Estresse Salino
11.
Plant Physiol Biochem ; 141: 291-299, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31202193

RESUMO

Silicon (Si) is reported to improve salt stress tolerance of cereals, but little is known about the effects of Si on flows and partitioning of sodium (Na+), chloride (Cl-), and essential mineral ions at the tissue and cellular level. Wheat (Triticum aestivum L.) was exposed to 200 mM NaCl for 30 d in hydroponics, with or without 2 mM Si. X-ray microanalysis coupled with scanning electron microscopy (SEM) was used to quantify the cell-specific ion profiles across root and leaf cells, paralleled by measurements of wheat growth and physiological responses. Under salt stress, higher Na+ and Cl- concentrations were detected in root epidermal, cortical and stelar cells, eventually increasing their concentrations in different leaf cells, being highest in the epidermal cells and lowest in the vascular bundle cells. The potassium (K+) and magnesium (Mg2+) profiles were generally opposite to those of Na+ and Cl-. NaCl-dependent deregulation of essential nutrient homeostasis and excessive toxic ions accumulation in leaves was correlated with enhanced electrolyte leakage index (ELI), decreased chlorophyll contents, photosynthesis and other physiological parameters, and ultimately hampered plant growth. Conversely, Si addition improved the growth and physiological performance of salinized wheat by reducing Na+ and Cl- concentration in root epidermal and cortical cells, and it improved root uptake and storage of K+ and Mg2+ ions and their loading into xylem for distribution to shoots. These results suggest that Si-mediated inhibition of Na+ uptake, maintained nutrient homeostasis and improved physiological parameters to contribute to wheat growth improvement under salt stress.


Assuntos
Tolerância ao Sal , Sais/química , Silício/química , Triticum/crescimento & desenvolvimento , Biomassa , Cloretos/química , Clorofila/química , Produtos Agrícolas/crescimento & desenvolvimento , Microanálise por Sonda Eletrônica , Genótipo , Homeostase , Hidroponia , Íons , Microscopia Eletrônica de Varredura , Minerais , Fotossíntese , Folhas de Planta/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Potássio/química , Salinidade , Plântula/crescimento & desenvolvimento , Sódio/química , Água/química
12.
Plant Sci ; 285: 55-67, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203894

RESUMO

C2H2-type zinc finger proteins play important roles in plant growth, development, and abiotic stress tolerance. Here, we explored the role of the C2H2-type zinc finger protein SALT INDUCED ZINC FINGER PROTEIN1 (AtSIZ1; At3G25910) in Arabidopsis thaliana under salt stress. AtSIZ1 expression was induced by salt treatment. During the germination stage, the germination rate, germination energy, germination index, cotyledon growth rate, and root length were significantly higher in AtSIZ1 overexpression lines than in the wild type under various stress treatments, whereas these indices were significantly reduced in AtSIZ1 loss-of-function mutants. At the mature seedling stage, the overexpression lines maintained higher levels of K+, proline, and soluble sugar, lower levels of Na+ and MDA, and lower Na+/K+ ratios than the wild type. Stress-related marker genes such as SOS1, AtP5CS1, AtGSTU5, COR15A, RD29A, and RD29B were expressed at higher levels in the overexpression lines than the wild type and loss-of-function mutants under salt treatment. These results indicate that AtSIZ1 improves salt tolerance in Arabidopsis by helping plants maintain ionic homeostasis and osmotic balance.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/metabolismo , Ligases/fisiologia , Dedos de Zinco/fisiologia , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Homeostase , Ligases/genética , Filogenia , Potássio/metabolismo , Prolina/metabolismo , Estresse Salino , Tolerância ao Sal , Sódio/metabolismo , Dedos de Zinco/genética
13.
Zoolog Sci ; 36(3): 215-222, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-31251490

RESUMO

Anurans occupy a wide variety of habitats of diverse salinities, and their osmoregulatory ability is strongly regulated by hormones. In this study, we compared the adaptability and hormonal responses to osmotic stress between two kajika frogs, Buergeria japonica (B.j.) and B. buergeri, (B.b.), which inhabit coastal brackish waters (BW) in the Ryukyu Islands and freshwater (FW) in the Honshu, respectively. Both hematocrit and plasma Na+ concentration were significantly higher in B.j. than in B.b. when both were kept in FW. After transfer to one-third seawater (simulating the natural BW environment), which is slightly hypertonic to their body fluids, their body mass decreased and plasma Na concentration increased significantly in both species. After transfer, plasma Na+ concentration increased significantly in both species. We examined the gene expression of two major osmoregulatory hormones, arginine vasotocin (AVT) and atrial natriuretic peptide (ANP), after partial cloning of their cDNAs. ANP mRNA levels were more than 10-fold higher in B.j. than in B.b. in FW, but no significant difference was observed for AVT mRNA levels due to high variability, although the mean value of B.j. was twice that of B.b. Both AVT and ANP mRNA levels increased significantly after transfer to BW in B.b. but not in B.j., probably because of the high levels in FW. These results suggest that B.j. maintains high plasma Na+ concentration and anp gene expression to prepare for the future encounter of the high salinity. The unique preparatory mechanism may allow B.j. wide distribution in oceanic islands.


Assuntos
Anuros/fisiologia , Ecossistema , Águas Salinas/química , Tolerância ao Sal/fisiologia , Animais , Fator Natriurético Atrial/metabolismo , Clonagem Molecular , Regulação da Expressão Gênica/efeitos dos fármacos , Japão , Masculino , Osmorregulação/fisiologia , RNA/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Cloreto de Sódio/farmacologia , Vasotocina/metabolismo
14.
Plant Cell Rep ; 38(9): 1151-1163, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31152194

RESUMO

KEY MESSAGE: Piriformospora indica confers salt tolerance in tomato seedlings by increasing the uptake of nutrients such as N, P and Ca, improving K+/Na+ homoeostasis by regulating the expression of NHXs, SOS1 and CNGC15 genes, maintaining water status by regulating the expression of aquaporins. Piriformospora indica, an endophytic basidiomycete, has been shown to increase the growth and improve the plants tolerance to stressful conditions, especially salinity, by establishing the arbuscular mycorrhiza-like symbiotic relationship in various plant hosts. In the present research, the effect of NaCl treatment (150 mM) and P. indica inoculation on growth, accumulation of nutrients, the transcription level of genes involved in ionic homeostasis (NHXs, SOS1 and CNGC15) and regulating water status (PIP1;2, PIP2;4, TIP1;1 and TIP2;2) in roots and leaves of tomato seedlings were investigated. The P. indica improved the uptake of N, P, Ca and K, and reduced Na accumulation, and had no significant effect on Cl accumulation in roots and leaves. The endophytic fungus also increased in K+/Na+ ratio in roots and leaves of tomato by regulating the expression of NHX isoforms and upregulating SOS1 and CNGC15 expression. Salinity stress increased the transcription of PIP2;4 gene and reduced the transcription of PIP1;2, TIP1;1 and TIP2;2 genes compared to the control treatment. However, P. indica inoculation upregulated the expression of PIP1;2 and PIP2;4 genes versus non-inoculated plants but did not have a significant effect on TIP1;1 and TIP2;2 expression. These results conclude that the positive effects of P. indica on nutrients accumulation, ionic homeostasis and water status lead to the increased salinity tolerance and the improved plant growth under NaCl treatment.


Assuntos
Basidiomycota/fisiologia , Lycopersicon esculentum/microbiologia , Nutrientes/metabolismo , Potássio/metabolismo , Sódio/metabolismo , Água/metabolismo , Homeostase , Lycopersicon esculentum/genética , Lycopersicon esculentum/fisiologia , Salinidade , Tolerância ao Sal , Estresse Fisiológico , Simbiose
15.
Plant Cell Rep ; 38(9): 1165-1180, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31161264

RESUMO

KEY MESSAGE: Arabidopsis photorespiratory gene AtAGT1 is important for the growth and development of root, the non-photosynthetic organ, and it is involved in a complex metabolic network and salt resistance. AtAGT1 in Arabidopsis encodes an aminotransferase that has a wide range of donor:acceptor combinations, including Asn:glyoxylate. Although it is one of the photorespiratory genes, its encoding protein has been suggested to function also in roots to metabolize Asn. However, experimental data are still lacking. In this study, we investigated experimentally the function of AtAGT1 in roots and our results uncovered its importance in root development during seedling establishment after seed germination. Overexpression of AtAGT1 in roots promoted both the growth of primary root and outgrowth of lateral roots. To further elucidate the molecular mechanisms underlying, amino acid content and gene expression in roots were analyzed, and results revealed that AtAGT1 is involved in a complex metabolic network and salt resistance of roots.


Assuntos
Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Reguladores de Crescimento de Planta/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Expressão Gênica , Germinação , Plantas Geneticamente Modificadas , Tolerância ao Sal , Plântula/genética , Plântula/crescimento & desenvolvimento , Plântula/fisiologia , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/fisiologia , Transaminases/genética , Transaminases/metabolismo
16.
Plant Physiol Biochem ; 141: 415-422, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31229926

RESUMO

This study aimed to investigate the possible alleviating effect of chitosan on salt-induced growth retardation and oxidative stress and to elucidate whether this effect is linked to activation of mitochondrial respiration on the basis of alternative respiration in maize seedlings. Salt stress significantly reduced root length and plant height in comparison to the control, whereas foliar application of chitosan ameliorated the adverse effect of salinity to a certain degree. Moreover, chitosan resulted in plant growth promotion as compared to unstressed seedlings. The separate applications of chitosan and salt had a stimulatory effect on the activities of antioxidant enzymes; however, combined application of chitosan and salt were more effective than that of chitosan or salt alone. Similarly, mitochondrial total respiration rate (Vt) and alternative respiration capacity (Valt) were increased by separate applications of chitosan and salt; however, the combination of chitosan and salt gave the highest values for these parameters. The highest values of Valt/Vt was recorded at seedlings treated with salt plus chitosan. Similarly, cytochrome respiration capacity was also increased by chitosan in both stress-free and stressed conditions. In addition, AOX1, encoding alternative oxidase, was significantly upregulated by chitosan and/or salt. The maximum transcript level was recorded at seedlings treated with salt plus chitosan. Chitosan also significantly decreased superoxide anion and hydrogen peroxide contents and lipid peroxidation level under normal and the stressed conditions. These results suggest that the mitigating effect of chitosan on salt stress is linked to activation of alternative respiration at biochemical and molecular level.


Assuntos
Quitosana/química , Regulação da Expressão Gênica de Plantas , Proteínas Mitocondriais/metabolismo , Oxirredutases/metabolismo , Proteínas de Plantas/metabolismo , Tolerância ao Sal , Plântula/genética , Zea mays/genética , Antioxidantes/metabolismo , Citocromos/metabolismo , Perfilação da Expressão Gênica , Peroxidação de Lipídeos , Mitocôndrias/metabolismo , Proteínas Mitocondriais/genética , Estresse Oxidativo , Oxirredutases/genética , Proteínas de Plantas/genética , RNA/metabolismo , Estresse Fisiológico , Zea mays/enzimologia
17.
Plant Physiol Biochem ; 141: 431-445, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31238253

RESUMO

S-adenosylmethionine synthetase (SAMS) catalyzes methionine and ATP to generate S-adenosyl-L-methionine (SAM). In plants, accumulating SAMS genes have been characterized and the majority of them are reported to participate in development and stress response. In this study, two putative SAMS genes (CsSAMS1 and CsSAMS2) were identified in cucumber (Cucumis Sativus L.). They displayed 95% similarity and had a high identity with their homologous of Arabidopsis thaliana and Nicotiana tabacum. The qRT-PCR test showed that CsSAMS1 was predominantly expressed in stem, male flower, and young fruit, whereas CsSAMS2 was preferentially accumulated in stem and female flower. And they displayed differential expression profiles under stimuli, including NaCl, ABA, SA, MeJA, drought and low temperature. To elucidate the function of cucumber SAMS, the full-length CDS of CsSAMS1 was cloned, and prokaryotic expression system and transgenic materials were constructed. Expressing CsSAMS1 in Escherichia coli BL21 (DE3) improved the growth of the engineered strain under salt stress. Overexpression of CsSAMS1 significantly increased MDA content, H2O2 content, and POD activity in transgenic lines under non-stress condition. Under salt stress, however, the MDA content of transgenic lines was lower than that of the wild type, the H2O2 content remained high, the polyamine and ACC synthesis in transgenic lines exhibited a CsSAMS1-expressed dependent way. Taken together, our results suggested that both CsSAMS1 and CsSAMS2 were involved in plant development and stress response, and a proper increase of expression level of CsSAMS1 in plants is benificial to improving salt tolerance.


Assuntos
Cucumis sativus/enzimologia , Cucumis sativus/fisiologia , Metionina Adenosiltransferase/metabolismo , Tolerância ao Sal , Antioxidantes/metabolismo , Arabidopsis/metabolismo , Secas , Perfilação da Expressão Gênica , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Peróxido de Hidrogênio/química , Metionina Adenosiltransferase/genética , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Poliaminas/química , Sais , Estresse Mecânico , Estresse Fisiológico/genética , Tabaco/metabolismo
18.
Plant Physiol Biochem ; 141: 446-455, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31247427

RESUMO

Coumarin plays a pivotal role in plant response to biotic stress, as well as in the mediation of nutrient acquisition. However, its functions in response to abiotic stresses are largely unknown. In this work, a homologous gene, GmF6'H1, of AtF6'H1, which encodes the enzyme catalyzing the final rate-limiting step in the biosynthesis pathway of coumarin, was isolated from soybean. GmF6'H1 protein shares very high amino acid identity with AtF6'H1, and expression of GmF6'H1 in atf6'h1 can successfully restore the decreased coumarin production in the T-DNA insertion mutant. Further study revealed that the expression of GmF6'H1 in soybean was remarkably induced by salt stress. Constitutive expression of GmF6'H1 in Arabidopsis, driven by 35S promoter, significantly enhanced the resistance to salt of transgenic Arabidopsis. All these results suggest that GmF6'H1 can be used as a potential candidate gene for the engineering of plants with improved resistance to both biotic and abiotic stresses.


Assuntos
Arabidopsis/fisiologia , Regulação da Expressão Gênica de Plantas , Tolerância ao Sal , Soja/enzimologia , Arabidopsis/genética , Clorofila/química , Clonagem Molecular , Cumarínicos/química , Perfilação da Expressão Gênica , Germinação , Fenótipo , Folhas de Planta/metabolismo , Plantas Geneticamente Modificadas/fisiologia , Regiões Promotoras Genéticas , Soja/genética
19.
Plant Physiol Biochem ; 140: 113-121, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31100704

RESUMO

Soil salinity is a major abiotic stress affecting plant growth and yield, due to both osmotic and ionic stresses. JUBGBRUNNEN1 (JUB1) is a NAC family transcription factor that has been shown to be involved in responses to abiotic stresses, such as water deficit, osmotic, salinity, heat and oxidative stress. In Arabidopsis thaliana (Arabidopsis), JUB1 has been shown to improve plant stress tolerance by regulating H2O2 levels. In the horticultural crop, Solanum lycopersicum cv. Moneymaker (tomato), overexpression of AtJUB1 has been shown to partially alleviate water deficit stress at the vegetative stage. In this study, we investigated the effect of Arabidopsis JUB1 overexpression in salinity tolerance in tomato. In hydroponically grown tomato seedlings, AtJUB1 overexpression results in higher prolines levels and improves the maintenance of water content in the plant under salinity stress. The transgenic tomato plants are more tolerant to salinity stress compared to control lines based on plant biomass. However, at the reproductive stage, we found that overexpression of AtJUB1 only provided marginal improvements in yield-related parameters, in the conditions used for the current work. The combination of improved water deficit and salinity stress tolerance conferred by AtJUB1 overexpression may be beneficial when tomato plants are grown in the field under marginal environments.


Assuntos
Arabidopsis/metabolismo , Lycopersicon esculentum/metabolismo , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Lycopersicon esculentum/efeitos dos fármacos , Proteínas de Plantas/genética , Prolina/metabolismo , Tolerância ao Sal , Cloreto de Sódio/farmacologia , Fatores de Transcrição/genética
20.
Plant Physiol Biochem ; 140: 151-157, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31103797

RESUMO

Na+/H+ antiporter (NHX), responsible for counter-transport of Na+ and H+ across membranes (Na+ compartmentalization), plays a central role in plant salt-tolerance. In order to explore the Na+ compartmentalization modes and salt tolerance strategy in Chinese cabbage (Brassica rapa L. ssp. pekinensis), the seedlings of a salt-susceptible cabbage cultivar (Kuaicai 38) and a salt-tolerant cabbage cultivar (Qingmaye) were exposed to 100-400 mM NaCl for 30 days. Both of these cultivars showed a gradual decrease in fresh weight and water content and an increase in root-shoot ratio with the increasing NaCl-treatment concentration. The distribution of Na+ in these two cultivars was similar, with the green leaves showing the highest Na+ content, followed by inflated midribs, stems, and roots. The Na+ concentration in the apoplast was higher than that in the protoplast of the leaves. The expression levels of BrNHX1-1 and BrNHX1-2 in the leaves of Qingmaye were the highest among all BrNHX members, and increased after salt treatment. However, only BrNHX1-1 was expressed in Kuaicai 38. These results indicate that Na+ compartmentation into vacuoles is the major salt-adaptation strategy in Chinese cabbage. Coordinated overexpression of BrNHX1-1 and BrNHX1-2 may confer greater salt-tolerance for Chinese cabbage.


Assuntos
Brassica/metabolismo , Sódio/metabolismo , Brassica/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Caules de Planta/efeitos dos fármacos , Caules de Planta/metabolismo , Estresse Salino , Tolerância ao Sal
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