Efficiency of antioxidant system in barrel medic (Medicago truncatula) genotypes and the orchestration of their key components under iron deficiency

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.

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A Mass Spectrometry-Based Study Shows that Volatiles Emitted by Arthrobacter agilis UMCV2 Increase the Content of Brassinosteroids in Medicago truncatula in Response to Iron Deficiency Stress

Molecules ◽

10.3390/molecules24163011 ◽

2019 ◽

Vol 24 (16) ◽

pp. 3011

Author(s):

Idolina Flores-Cortez ◽

Robert Winkler ◽

Arturo Ramírez-Ordorica ◽

Ma. Isabel Cristina Elizarraraz-Anaya ◽

María Teresa Carrillo-Rayas ◽

...

Keyword(s):

Mass Spectrometry ◽

Iron Deficiency ◽

Medicago Truncatula ◽

Stress Responses ◽

Crop Yields ◽

Abiotic Factors ◽

Defense Responses ◽

Iron Deficient ◽

Arthrobacter Agilis ◽

Microbial Volatiles

Iron is an essential plant micronutrient. It is a component of numerous proteins and participates in cell redox reactions; iron deficiency results in a reduction in nutritional quality and crop yields. Volatiles from the rhizobacterium Arthrobacter agilis UMCV2 induce iron acquisition mechanisms in plants. However, it is not known whether microbial volatiles modulate other metabolic plant stress responses to reduce the negative effect of iron deficiency. Mass spectrometry has great potential to analyze metabolite alterations in plants exposed to biotic and abiotic factors. Direct liquid introduction-electrospray-mass spectrometry was used to study the metabolite profile in Medicago truncatula due to iron deficiency, and in response to microbial volatiles. The putatively identified compounds belonged to different classes, including pigments, terpenes, flavonoids, and brassinosteroids, which have been associated with defense responses against abiotic stress. Notably, the levels of these compounds increased in the presence of the rhizobacterium. In particular, the analysis of brassinolide by gas chromatography in tandem with mass spectrometry showed that the phytohormone increased ten times in plants grown under iron-deficient growth conditions and exposed to microbial volatiles. In this mass spectrometry-based study, we provide new evidence on the role of A. agilis UMCV2 in the modulation of certain compounds involved in stress tolerance in M. truncatula.

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Release of Medicago truncatula Gaertn. and Pisum sativum subsp. elatius (M. Bieb.) Asch. et Graebn. Seed Dormancy Tested in Soil Conditions

Agronomy ◽

10.3390/agronomy10071026 ◽

2020 ◽

Vol 10 (7) ◽

pp. 1026

Author(s):

Juan Pablo Renzi ◽

Jan Brus ◽

Stergios Pirintsos ◽

László Erdős ◽

Martin Duchoslav ◽

...

Keyword(s):

Pisum Sativum ◽

Medicago Truncatula ◽

Seed Dormancy ◽

Environmental Conditions ◽

Common Garden ◽

Soil Conditions ◽

Bet Hedging ◽

Soil Burial ◽

Barrel Medic ◽

Experimental Laboratory

Medicago truncatula (barrel medic) and Pisum sativum subsp. elatius (wild pea) accessions originating from variable environmental conditions in the Mediterranean basin were used to study physical seed dormancy (PY) release. The effect of soil burial on PY release was tested on 112 accessions of medic and 46 accessions of pea over the period of 3 months in situ at three common gardens (Hungary, Spain and Greece) from 2017 through 2019. PY release after soil exhumation followed by experimental laboratory germination of remaining dormant seeds (wet, 25 °C, 21 days) were related to the environmental conditions of the common garden and macroclimatic variables of the site of origin of the accessions. Higher PY release was observed in buried seeds under humid rather than under dry and hot environments. Exposure of remaining dormant seeds to experimental laboratory conditions increased total PY release up to 70% and 80% in barrel medic and wild pea, respectively. Wild pea showed higher phenotypic plasticity on PY release than barrel medic, which had higher bet-hedging within-season. Wild pea showed lower bet-hedging among-season (PY < 10%) in relation to precipitation than barrel medic, which was more conservative (PY ≈ 20%). Observed variability suggests that these species have the capability to cope with ongoing climate change.

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Inheritance of three marker characters in Medicago truncatula Gaertn. (M. tribuloides Desr.)

Australian Journal of Agricultural Research ◽

10.1071/ar9650031 ◽

1965 ◽

Vol 16 (1) ◽

pp. 31 ◽

Cited By ~ 3

Author(s):

JP Simon

Keyword(s):

Medicago Truncatula ◽

Recessive Gene ◽

Morphological Characters ◽

Anthocyanin Pigmentation ◽

Genetic Studies ◽

Seed Certification ◽

Pigmentation Pattern ◽

Barrel Medic ◽

Complete Penetrance ◽

Dominant Genes

The inheritance has been studied of three morphological characters which could be used as markers in the "pure seed" certification of commercial varieties of barrel medic, M. truncatula Gaertn. The leaf anthocyanin pigmentation pattern, as found in accession No. 2829, and the clockwise form of pod coiling characterizing accession No. 3309, are determined by single dominant genes. The spineless character of the pod of accession No. 2822 is due to a recessive gene. The simple inheritance of these characters and the complete penetrance of the genes concerned indicate that the anthocyanin marker and the spineless pod could be used for certification. Since the clockwise-anticlockwise pattern of coiling occurs in both forms in commercial barrel medic varieties, it is likely to be useful only as a marker in genetic studies. Details are given of a satisfactory procedure developed for crossing medic varieties

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Sulphur and phosphorus fertilizers increase the yield of barrel medic (Medicago truncatula) five-fold in native pasture on a traprock soil

Australian Journal of Experimental Agriculture ◽

10.1071/ea9890527 ◽

1989 ◽

Vol 29 (4) ◽

pp. 527 ◽

Cited By ~ 2

Author(s):

NM Clarkson ◽

IF Swann ◽

NP Chaplain

Keyword(s):

Medicago Truncatula ◽

Elemental Sulfur ◽

Nitrogen Concentration ◽

Nutrient Concentrations ◽

Phosphorus Concentration ◽

First Year ◽

Yield Increase ◽

Barrel Medic ◽

Yield And Quality ◽

Native Pasture

A single application of sulfur and phosphorus in the first year produced a 5-fold yield increase in barrel medic (Medicago truncatula cv. Jemalong), every year for 3 years, on traprock country in southern inland Queensland. In the first year, the yield of medic increased from 400 (untreated) to 1300 kg/ha with sulfur alone (at 40 kg/ha), and to 2300 kg /ha with sulfur and phosphorus together (both at 40 kg/ha). In the second and third years, sulfur and phosphorus together increased yields from 300 to 1400 kg/ha, and from 800 to 4000 kg/ha, respectively. The experiment tested factorial combinations of sulfur and phosphorus, both at 0, 10 and 40 kg/ha, 3 sources of sulfur (gypsum, superphosphate fortified with elemental sulfur and called 'super and sulfur', and elemental sulfur) and agricultural limestone at 2500 kg/ha. Seed and fertiliser were broadcast into a native pasture at the start of the experiment. Elemental sulfur was inferior to gypsum and 'super and sulfur' in the first year, but equally effective thereafter. There was no response to lime. Fertilising with sulfur and phosphorus together increased the sulfur concentration in medic tops from 0.10 to 0.23%, the phosphorus concentration from 0.19 to 0.23%, and the nitrogen concentration from 2.12 to 2.82%. Nutrient concentrations in plant and soil were examined as an aid to diagnosing deficiencies at other sites. We concluded that adequately fertilising medic with sulfur and phosphorus can greatly improve pasture yield and quality, and allow higher stocking rates on traprock country.

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Bacterial Compound N,N-Dimethylhexadecylamine Modulates Expression of Iron Deficiency and Defense Response Genes in Medicago truncatula Independently of the Jasmonic Acid Pathway

Plants ◽

10.3390/plants9050624 ◽

2020 ◽

Vol 9 (5) ◽

pp. 624 ◽

Cited By ~ 1

Author(s):

Vicente Montejano-Ramírez ◽

Ernesto García-Pineda ◽

Eduardo Valencia-Cantero

Keyword(s):

Gene Expression ◽

Salicylic Acid ◽

Iron Deficiency ◽

Jasmonic Acid ◽

Pseudomonas Syringae ◽

Medicago Truncatula ◽

Abiotic Stresses ◽

Biotic And Abiotic Stresses ◽

Iron Deprivation ◽

Iron Deficient

Plants face a variety of biotic and abiotic stresses including attack by microbial phytopathogens and nutrient deficiencies. Some bacterial volatile organic compounds (VOCs) activate defense and iron-deficiency responses in plants. To establish a relationship between defense and iron deficiency through VOCs, we identified key genes in the defense and iron-deprivation responses of the legume model Medicago truncatula and evaluated the effect of the rhizobacterial VOC N,N-dimethylhexadecylamine (DMHDA) on the gene expression in these pathways by RT-qPCR. DMHDA increased M. truncatula growth 1.5-fold under both iron-sufficient and iron-deficient conditions compared with untreated plants, whereas salicylic acid and jasmonic acid decreased growth. Iron-deficiency induced iron uptake and defense gene expression. Moreover, the effect was greater in combination with DMHDA. Salicylic acid, Pseudomonas syringae, jasmonic acid, and Botrytis cinerea had inhibitory effects on growth and iron response gene expression but activated defense genes. Taken together, our results showed that the VOC DMHDA activates defense and iron-deprivation pathways while inducing a growth promoting effect unlike conventional phytohormones, highlighting that DMHDA does not mimic jasmonic acid but induces an alternative pathway. This is a novel aspect in the complex interactions between biotic and abiotic stresses.

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