scholarly journals Inoculation with Efficient Nitrogen Fixing and Indoleacetic Acid Producing Bacterial Microsymbiont Enhance Tolerance of the Model LegumeMedicago truncatulato Iron Deficiency

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Nadia Kallala ◽  
Wissal M’sehli ◽  
Karima Jelali ◽  
Zribi Kais ◽  
Haythem Mhadhbi
Keyword(s):  
Oxidative Stress ◽  
Iron Deficiency ◽  
Medicago Truncatula ◽  
Sinorhizobium Meliloti ◽  
Plant Biomass ◽  
High Growth ◽  
Fe Deficiency ◽  
Nitrogen Fixing ◽  
Bacterial Strains ◽  
Negative Effect

The aim of this study was to assess the effect of symbiotic bacteria inoculation on the response ofMedicago truncatulagenotypes to iron deficiency. The present work was conducted on threeMedicago truncatulagenotypes: A17, TN8.20, and TN1.11. Three treatments were performed: control (C), direct Fe deficiency (DD), and induced Fe deficiency by bicarbonate (ID). Plants were nitrogen-fertilized (T) or inoculated with two bacterial strains:Sinorhizobium melilotiTII7 andSinorhizobium medicaeSII4. Biometric, physiological, and biochemical parameters were analyzed. Iron deficiency had a significant lowering effect on plant biomass and chlorophyll content in allMedicago truncatulagenotypes. TN1.11 showed the highest lipid peroxidation and leakage of electrolyte under iron deficiency conditions, which suggest that TN1.11 was more affected than A17 and TN8.20 by Fe starvation. Iron deficiency affected symbiotic performance indices of allMedicago truncatulagenotypes inoculated with bothSinorhizobiumstrains, mainly nodules number and biomass as well as nitrogen-fixing capacity. Nevertheless, inoculation withSinorhizobiumstrains mitigates the negative effect of Fe deficiency on plant growth and oxidative stress compared to nitrogen-fertilized plants. The highest auxin producing strain, TII7, preserves relatively high growth and root biomass and length when inoculated to TN8.20 and A17. On the other hand, both TII7 and SII4 strains improve the performance of sensitive genotype TN1.11 through reduction of the negative effect of iron deficiency on chlorophyll and plant Fe content. The bacterial inoculation improved Fe-deficient plant response to oxidative stress via the induction of the activities of antioxidant enzymes.

scholarly journals Specific Host-Responsive Associations Between Medicago truncatula Accessions and Sinorhizobium Strains

2017 ◽  
Vol 30 (5) ◽  
pp. 399-409 ◽  
Author(s):  
Théophile Kazmierczak ◽  
Marianna Nagymihály ◽  
Florian Lamouche ◽  
Quentin Barrière ◽  
Ibtissem Guefrachi ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Sinorhizobium Meliloti ◽  
Root Nodules ◽  
Nodule Formation ◽  
Bacterial Strains ◽  
Symbiotic Efficiency ◽  
Model Legume ◽  
Functional Studies ◽  
Multiple Parameters ◽  
Nitrogen Fixation Activity

Legume plants interact with rhizobia to form nitrogen-fixing root nodules. Legume-rhizobium interactions are specific and only compatible rhizobia and plant species will lead to nodule formation. Even within compatible interactions, the genotype of both the plant and the bacterial symbiont will impact on the efficiency of nodule functioning and nitrogen-fixation activity. The model legume Medicago truncatula forms nodules with several species of the Sinorhizobium genus. However, the efficiency of these bacterial strains is highly variable. In this study, we compared the symbiotic efficiency of Sinorhizobium meliloti strains Sm1021, 102F34, and FSM-MA, and Sinorhizobium medicae strain WSM419 on the two widely used M. truncatula accessions A17 and R108. The efficiency of the interactions was determined by multiple parameters. We found a high effectiveness of the FSM-MA strain with both M. truncatula accessions. In contrast, specific highly efficient interactions were obtained for the A17-WSM419 and R108-102F34 combinations. Remarkably, the widely used Sm1021 strain performed weakly on both hosts. We showed that Sm1021 efficiently induced nodule organogenesis but cannot fully activate the differentiation of the symbiotic nodule cells, explaining its weaker performance. These results will be informative for the selection of appropriate rhizobium strains in functional studies on symbiosis using these M. truncatula accessions, particularly for research focusing on late stages of the nodulation process.

scholarly journals Transcriptomic Analysis of Sinorhizobium meliloti and Medicago truncatula Symbiosis Using Nitrogen Fixation–Deficient Nodules

2015 ◽  
Vol 28 (8) ◽  
pp. 856-868 ◽  
Author(s):  
Claus Lang ◽  
Sharon R. Long
Keyword(s):  
Gene Expression ◽  
Nitrogen Fixation ◽  
Bacterial Infection ◽  
Medicago Truncatula ◽  
Sinorhizobium Meliloti ◽  
Cell Envelope ◽  
Root Nodules ◽  
Bacterial Cells ◽  
Nitrogen Fixing ◽  
Bacterial Genes

The bacterium Sinorhizobium meliloti interacts symbiotically with legume plant hosts such as Medicago truncatula to form nitrogen-fixing root nodules. During symbiosis, plant and bacterial cells differentiate in a coordinated manner, resulting in specialized plant cells that contain nitrogen-fixing bacteroids. Both plant and bacterial genes are required at each developmental stage of symbiosis. We analyzed gene expression in nodules formed by wild-type bacteria on six plant mutants with defects in nitrogen fixation. We observed differential expression of 482 S. meliloti genes with functions in cell envelope homeostasis, cell division, stress response, energy metabolism, and nitrogen fixation. We simultaneously analyzed gene expression in M. truncatula and observed differential regulation of host processes that may trigger bacteroid differentiation and control bacterial infection. Our analyses of developmentally arrested plant mutants indicate that plants use distinct means to control bacterial infection during early and late symbiotic stages.

scholarly journals Polyamines produced by Sinorhizobium meliloti Rm8530 contribute to symbiotically relevant phenotypes ex planta and to nodulation efficiency on alfalfa

Microbiology ◽  
2020 ◽  
Vol 166 (3) ◽  
pp. 278-287 ◽  
Author(s):  
Victor A. Becerra-Rivera ◽  
Alejandra Arteaga ◽  
Alfonso Leija ◽  
Georgina Hernández ◽  
Michael F. Dunn
Keyword(s):  
Oxidative Stress ◽  
Sinorhizobium Meliloti ◽  
Dry Weight ◽  
Nitrogen Fixing ◽  
Wild Type ◽  
Content Type ◽  
Phenotypic Differences ◽  
Nodule Biomass ◽  
Increased Sensitivity ◽  
Exogenous Spermidine

In nitrogen-fixing rhizobia, emerging evidence shows significant roles for polyamines in growth and abiotic stress resistance. In this work we show that a polyamine-deficient ornithine decarboxylase null mutant (odc2) derived from Sinorhizobium meliloti Rm8530 had significant phenotypic differences from the wild-type, including greatly reduced production of exopolysaccharides (EPS; ostensibly both succinoglycan and galactoglucan), increased sensitivity to oxidative stress and decreased swimming motility. The introduction of the odc2 gene borne on a plasmid into the odc2 mutant restored wild-type phenotypes for EPS production, growth under oxidative stress and swimming. The production of calcofluor-binding EPS (succinoglycan) by the odc2 mutant was also completely or mostly restored in the presence of exogenous spermidine (Spd), norspermidine (NSpd) or spermine (Spm). The odc2 mutant formed about 25 % more biofilm than the wild-type, and its ability to form biofilm was significantly inhibited by exogenous Spd, NSpd or Spm. The odc2 mutant formed a less efficient symbiosis with alfalfa, resulting in plants with significantly less biomass and height, more nodules but less nodule biomass, and 25 % less nitrogen-fixing activity. Exogenously supplied Put was not able to revert these phenotypes and caused a similar increase in plant height and dry weight in uninoculated plants and in those inoculated with the wild-type or odc2 mutant. We discuss ways in which polyamines might affect the phenotypes of the odc2 mutant.

scholarly journals Nodule-Specific Cysteine-Rich Peptides Negatively Regulate Nitrogen-Fixing Symbiosis in a Strain-Specific Manner in Medicago truncatula

2018 ◽  
Vol 31 (2) ◽  
pp. 240-248 ◽  
Author(s):  
Qi Wang ◽  
Jinge Liu ◽  
Hua Li ◽  
Shengming Yang ◽  
Peter Körmöczi ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Sinorhizobium Meliloti ◽  
Molecular Mechanisms ◽  
Nodule Development ◽  
Nitrogen Fixing ◽  
Plant Genotype ◽  
Specific Manner ◽  
Meliloti Strain ◽  
High Level ◽  
Symbiotic Partner

Medicago truncatula shows a high level of specificity when interacting with its symbiotic partner Sinorhizobium meliloti. This specificity is mainly manifested at the nitrogen-fixing stage of nodule development, such that a particular bacterial strain forms nitrogen-fixing nodules (Nod+/Fix+) on one plant genotype but ineffective nodules (Nod+/Fix−) on another. Recent studies have just begun to reveal the underlying molecular mechanisms that control this specificity. The S. meliloti strain A145 induces the formation of Fix+ nodules on the accession DZA315.16 but Fix− nodules on Jemalong A17. A previous study reported that the formation of Fix− nodules on Jemalong A17 by S. meliloti A145 was conditioned by a single recessive allele named Mtsym6. Here we demonstrate that the specificity associated with S. meliloti A145 is controlled by multiple genes in M. truncatula, including NFS1 and NFS2 that encode nodule-specific cysteine-rich (NCR) peptides. The two NCR peptides acted dominantly to block rather than promote nitrogen fixation by S. meliloti A145. These two NCR peptides are the same ones that negatively regulate nitrogen-fixing symbiosis associated with S. meliloti Rm41.

scholarly journals Nitric Oxide Is Formed in Medicago truncatula-Sinorhizobium meliloti Functional Nodules

2006 ◽  
Vol 19 (9) ◽  
pp. 970-975 ◽  
Author(s):  
Emmanuel Baudouin ◽  
Laurent Pieuchot ◽  
Gilbert Engler ◽  
Nicolas Pauly ◽  
Alain Puppo
Keyword(s):  
Nitric Oxide ◽  
Medicago Truncatula ◽  
Sinorhizobium Meliloti ◽  
No Synthase ◽  
Environmental Cues ◽  
No Production ◽  
Bacterial Strains ◽  
Symbiotic Interactions ◽  
Synthase Inhibitor ◽  
Plant Pathogen Interactions

Nitric oxide (NO) has recently gained interest as a major signaling molecule during plant development and response to environmental cues. Its role is particularly crucial for plant-pathogen interactions, during which it participates in the control of plant defense response and resistance. Indication for the presence of NO during symbiotic interactions has also been reported. Here, we defined when and where NO is produced during Medicago truncatula-Sinorhizobium meliloti symbiosis. Using the NO-specific fluorescent probe 4,5-diaminofluorescein diacetate, NO production was detected by confocal microscopy in functional nodules. NO production was localized in the bacteroid-containing cells of the nodule fixation zone. The infection of Medicago roots with bacterial strains impaired in nitrogenase or nitrite reductase activities lead to the formation of nodules with an unaffected NO level, indicating that neither nitrogen fixation nor denitrification pathways are required for NO production. On the other hand, the NO synthase inhibitor N-methyl-L-arginine impaired NO detection, suggesting that a NO synthase may participate to NO production in nodules. These data indicate that a NO production occurs in functional nodules. The location of such a production in fully metabolically active cells raises the hypothesis of a new function for NO during this interaction unrelated to defense and cell-death activation.

scholarly journals A proteomic atlas of the legume Medicago truncatula and its nitrogen-fixing endosymbiont Sinorhizobium meliloti

2016 ◽  
Vol 34 (11) ◽  
pp. 1198-1205 ◽  
Author(s):  
Harald Marx ◽  
Catherine E Minogue ◽  
Dhileepkumar Jayaraman ◽  
Alicia L Richards ◽  
Nicholas W Kwiecien ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Sinorhizobium Meliloti ◽  
Nitrogen Fixing

The mechanisms involved in obesity-induced male infertility

2020 ◽  
Vol 16 ◽  
Author(s):  
Hamed Heydari ◽  
Rafighe Ghiasi ◽  
Saber Ghaderpour ◽  
Rana Keyhanmanesh
Keyword(s):  
Oxidative Stress ◽  
Metabolic Disease ◽  
Male Infertility ◽  
Male Fertility ◽  
Reproductive Function ◽  
Disease Development ◽  
Significant Evidence ◽  
Male Reproductive Function ◽  
Negative Effect ◽  
And Oxidative Stress

Introduction: Obesity resulted by imbalance between the intake of energy and energy consumption can lead to growth and metabolic disease development in people. Both in obese men and animal models, several studies indicate that obesity leads to male infertility. Objective: This review has discussed some mechanisms involved in obesity-induced male infertility. Method: Online documents were searched through Science Direct, Pubmed, Scopus, and Google Scholar websites dating from 1959 to recognize studies on obesity, kisspeptin, leptin, and infertility. Results: Obesity induced elevated inflammatory cytokines and oxidative stress can affect male reproductive functions including spermatogenesis disorders, reduced male fertility power and hormones involved in hypothalamus-pituitarygonadal axis. Conclusion: There is significant evidence that obesity resulted in male infertility. obesity has negative effect on male reproductive function via several mechanisms such as inflammation and oxidative stress.

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