Rhamnolipid Enhances the Nitrogen Fixation Activity of Azotobacter chroococcum by Influencing Lysine Succinylation

The enhancement of nitrogen fixation activity of diazotrophs is essential for safe crop production. Lysine succinylation (KSuc) is widely present in eukaryotes and prokaryotes and regulates various biological process. However, knowledge of the extent of KSuc in nitrogen fixation of Azotobacter chroococcum is scarce. In this study, we found that 250 mg/l of rhamnolipid (RL) significantly increased the nitrogen fixation activity of A. chroococcum by 39%, as compared with the control. Real-time quantitative reverse transcription PCR (qRT-PCR) confirmed that RL could remarkably increase the transcript levels of nifA and nifHDK genes. In addition, a global KSuc of A. chroococcum was profiled using a 4D label-free quantitative proteomic approach. In total, 5,008 KSuc sites were identified on 1,376 succinylated proteins. Bioinformatics analysis showed that the addition of RL influence on the KSuc level, and the succinylated proteins were involved in various metabolic processes, particularly enriched in oxidative phosphorylation, tricarboxylic acid cycle (TCA) cycle, and nitrogen metabolism. Meanwhile, multiple succinylation sites on MoFe protein (NifDK) may influence nitrogenase activity. These results would provide an experimental basis for the regulation of biological nitrogen fixation with KSuc and shed new light on the mechanistic study of nitrogen fixation.

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Root Distribution and Nitrogen Fixation Activity of Tropical Forage Legume American Jointvetch (Aeschynomene americanaL.) cv. Glenn under Waterlogging Conditions

International Journal of Agronomy ◽

10.1155/2014/507405 ◽

2014 ◽

Vol 2014 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Manabu Tobisa ◽

Masataka Shimojo ◽

Yasuhisa Masuda

Keyword(s):

Nitrogen Fixation ◽

Root Distribution ◽

Water Surface ◽

Nitrogenase Activity ◽

Soil Surface ◽

Nodule Formation ◽

Nitrogen Fixation Activity ◽

Fixation Activity ◽

Net Assimilation ◽

Waterlogging Treatment

We investigated the root distribution and nitrogen fixation activity of American jointvetch (Aeschynomene americanaL.) cv. Glenn, under waterlogging treatment. The plants were grown in pots under three different treatments: no waterlogging (control), 30 days of waterlogging (experiment 1), and 40 days of waterlogging (experiment 2). The plants were subjected to the treatments on day 14 after germination. Root dry matter (DM) weight distribution of waterlogged plants was shallower than controls after day 20 of waterlogging. Throughout the study period, the total root DM weight in waterlogged plants was similar to that in the controls. Enhanced rooting (adventitious roots) and nodule formation at the stem base were observed in waterlogged plants after day 20 of waterlogging. The average DM weight of individual nodules on the region of the stem between the soil surface and water surface of waterlogged plants was similar to that of individual taproot nodules in the controls. Waterlogged plants had slightly greater plant DM weight than the controls after 40 days of treatment. The total nitrogenase activity (TNA) of nodules and nodule DM weight were higher in waterlogged plants than in the controls. Waterlogged American jointvetch had roots with nodules both around the soil surface and in the area between the soil surface and water surface after 20 days of waterlogging, and they maintained high nitrogenase activity and net assimilation rate that resulted in an increased growth rate.

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Biological Nitrogen Fixation and Denitrification in Rhizosphere of Potato Plants in Response to the Fertilization and Inoculation

Frontiers in Sustainable Food Systems ◽

10.3389/fsufs.2021.606379 ◽

2021 ◽

Vol 5 ◽

Author(s):

Vitaliy V. Volkogon ◽

Svitlana B. Dimova ◽

Kateryna I. Volkogon ◽

Vasyl P. Sidorenko ◽

Mykola V. Volkogon

Keyword(s):

Nitrogen Fixation ◽

Green Manure ◽

Crop Yields ◽

Nitrogenase Activity ◽

Farmyard Manure ◽

Mineral Fertilizers ◽

Potato Plants ◽

Nitrogen Fixation Activity ◽

Fixation Activity ◽

Fertilizer Rates

The study aim was to evaluate the potential nitrogen fixation and denitrification in the rhizosphere soil of potato plants, crop yield and output quality in response to the different fertilization systems and the inoculation with Azospirillum brasilense 410. Field stationary experiment was conducted between 2016 and 2019 with potato in a crop rotation system on leached chernozem soil. Farmyard manure, 40 t/ha, applied prior to potatoes planting promotes nitrogen fixation (0.8–2.0 times compared to control). However, it has also affected denitrification (in 1.4–2.2 times higher compared to control). The lowest rate of mineral fertilizers used in the experiment, N40P40K40, was shown as most environmentally feasible. Under its use the increase of soil nitrogenase activity and low denitrification levels were observed. Same trends were also noted for the medium fertilizer rate, N80P80K80. The highest doses of mineral fertilizers, N120P120K120, substantially affected the denitrification process and reduced the nitrogen fixation activity (in 1.9–2.2 times). The combination of manure with the medium fertilizers rate has also resulted in high denitrification levels, while the soil nitrogen fixation activity has restored only at flowering stage. Crop inoculation with A. brasilense combined with the manure application, has not affected studied processes. However, crop inoculation after the green manure intercropping has shown the growth of nitrogenase activity. Used on the mineral fertilizers background inoculation has activated nitrogen fixation and has ensured the decrease of denitrification levels, subject to the fertilization background. High fertilizer rates have hampered the inoculation efficiency. Inoculation has promoted crop yields on unfertilized and mineral backgrounds or following green manure. Crop inoculation following organic and the organo-mineral backgrounds had no significant effect, probably due to the competition for A. brasilense from microorganisms that have created a competitive environment for A. brasilense. Despite its environmental expediency, inoculation combined with the low fertilizer doses underperforms the action of inoculation combined with the medium fertilizer rates showing the latter as the compromise between the environmental requirements and crop productivity. The use of inoculation has promoted the accumulation of starch and ascorbic acid and has contributed to the reduction of nitrate contents in the tubers of inoculated plants.

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Engineering Nitrogen Fixation Activity in an Oxygenic Phototroph

mBio ◽

10.1128/mbio.01029-18 ◽

2018 ◽

Vol 9 (3) ◽

Cited By ~ 10

Author(s):

Deng Liu ◽

Michelle Liberton ◽

Jingjie Yu ◽

Himadri B. Pakrasi ◽

Maitrayee Bhattacharyya-Pakrasi

Keyword(s):

Nitrogen Fixation ◽

Energy Demand ◽

Nitrogenase Activity ◽

Crop Plants ◽

Nitrogen Fertilizers ◽

Widespread Application ◽

Nitrogen Fixation Activity ◽

Fixation Activity ◽

Photosynthetic Organism ◽

Oxygenic Phototroph

ABSTRACTBiological nitrogen fixation is catalyzed by nitrogenase, a complex metalloenzyme found only in prokaryotes. N2fixation is energetically highly expensive, and an energy-generating process such as photosynthesis can meet the energy demand of N2fixation. However, synthesis and expression of nitrogenase are exquisitely sensitive to the presence of oxygen. Thus, engineering nitrogen fixation activity in photosynthetic organisms that produce oxygen is challenging. Cyanobacteria are oxygenic photosynthetic prokaryotes, and some of them also fix N2. Here, we demonstrate a feasible way to engineer nitrogenase activity in the nondiazotrophic cyanobacteriumSynechocystissp. PCC 6803 through the transfer of 35 nitrogen fixation (nif) genes from the diazotrophic cyanobacteriumCyanothecesp. ATCC 51142. In addition, we have identified the minimalnifcluster required for such activity inSynechocystis6803. Moreover, nitrogenase activity was significantly improved by increasing the expression levels ofnifgenes. Importantly, the O2tolerance of nitrogenase was enhanced by introduction of uptake hydrogenase genes, showing this to be a functional way to improve nitrogenase enzyme activity under micro-oxic conditions. To date, our efforts have resulted in engineeredSynechocystis6803 strains that, remarkably, have more than 30% of the N2fixation activity ofCyanothece51142, the highest such activity established in any nondiazotrophic oxygenic photosynthetic organism. This report establishes a baseline for the ultimate goal of engineering nitrogen fixation ability in crop plants.IMPORTANCEApplication of chemically synthesized nitrogen fertilizers has revolutionized agriculture. However, the energetic costs of such production processes and the widespread application of fertilizers have raised serious environmental issues. A sustainable alternative is to endow to crop plants the ability to fix atmospheric N2in situ. One long-term approach is to transfer allnifgenes from a prokaryote to plant cells and to express nitrogenase in an energy-producing organelle, chloroplast, or mitochondrion. In this context,Synechocystis6803, the nondiazotrophic cyanobacterium utilized in this study, provides a model chassis for rapid investigation of the necessary requirements to establish diazotrophy in an oxygenic phototroph.

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Carbon Dots Enhance the Nitrogen Fixation Activity of Azotobacter Chroococcum

ACS Applied Materials & Interfaces ◽

10.1021/acsami.8b03758 ◽

2018 ◽

Vol 10 (19) ◽

pp. 16308-16314 ◽

Cited By ~ 10

Author(s):

Huibo Wang ◽

Hao Li ◽

Mengling Zhang ◽

Yuxiang Song ◽

Jian Huang ◽

...

Keyword(s):

Nitrogen Fixation ◽

Carbon Dots ◽

Azotobacter Chroococcum ◽

Nitrogen Fixation Activity ◽

Fixation Activity

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Engineering Nitrogen Fixation Activity in an Oxygenic Phototroph

10.1101/316547 ◽

2018 ◽

Author(s):

Deng Liu ◽

Michelle Liberton ◽

Jingjie Yu ◽

Himadri B. Pakrasi ◽

Maitrayee Bhattacharyya-Pakrasi

Keyword(s):

Nitrogen Fixation ◽

Energy Demand ◽

Nitrogenase Activity ◽

Crop Plants ◽

Nitrogen Fertilizers ◽

Nitrogen Fixation Activity ◽

Fixation Activity ◽

Photosynthetic Organism ◽

Biological Nitrogen ◽

Oxygenic Phototroph

ABSTRACTBiological nitrogen fixation is catalyzed by nitrogenase, a complex metalloenzyme found only in prokaryotes. N2fixation is energetically highly expensive, and an energy generating process such as photosynthesis can meet the energy demand of N2fixation. However, synthesis and expression of nitrogenase is exquisitely sensitive to oxygen. Thus, engineering nitrogen fixation activity in photosynthetic organisms that produce oxygen is challenging. Cyanobacteria are oxygenic photosynthetic prokaryotes, and some of them also fix N2. Here, we demonstrate a feasible way to engineer nitrogenase activity in the non-diazotrophic cyanobacteriumSynechocystissp. PCC 6803 through the transfer of 35 nitrogen fixation (nif) genes from the diazotrophic cyanobacteriumCyanothecesp. ATCC 51142. In addition, we have identified the minimalnifcluster required for such activity inSynechocystis6803. Moreover, nitrogenase activity was significantly improved by increasing the expression levels ofnifgenes. Importantly, the O2tolerance of nitrogenase was enhanced by introduction of uptake hydrogenase genes, showing this to be a functional way to improve nitrogenase enzyme activity under micro-oxic conditions. To date, our efforts have resulted in engineeredSynechocystis6803 strains that remarkably have more than 30% N2-fixation activity compared to that inCyanothece51142, the highest such activity established in any non-diazotrophic oxygenic photosynthetic organism. This study establishes a baseline towards the ultimate goal of engineering nitrogen fixation ability in crop plants.IMPORTANCEApplication of chemically synthesized nitrogen fertilizers has revolutionized agriculture. However, the energetic costs of such production processes as well as the wide spread application of fertilizers have raised serious environmental issues. A sustainable alternative is to endow crop plants the ability to fix atmospheric N2in situ. One long-term approach is to transfer allnifgenes from a prokaryote to plant cells, and express nitrogenase in an energy-producing organelle, chloroplast or mitochondrion. In this context,Synechocystis6803, the non-diazotrophic cyanobacterium utilized in this study, provides a model chassis for rapid investigation of the necessary requirements to establish diazotrophy in an oxygenic phototroph.

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The effect of inoculation of pea plants with mycorrhizal fungi and Rhizobium on nitrogen and phosphorus assimilation

Plant Soil and Environment ◽

10.17221/3463-pse ◽

2011 ◽

Vol 52 (No. 10) ◽

pp. 435-440 ◽

Cited By ~ 27

Author(s):

M. Geneva ◽

G. Zehirov ◽

E. Djonova ◽

N. Kaloyanova ◽

G. Georgiev ◽

...

Keyword(s):

Nitrogen Fixation ◽

Mycorrhizal Fungi ◽

Glomus Mosseae ◽

Rhizobium Leguminosarum ◽

Glomus Intraradices ◽

Plant Biomass ◽

Phosphorus Level ◽

Nitrogen And Phosphorus ◽

Nitrogen Fixation Activity ◽

Fixation Activity

The study evaluated the response of pea (Pisum sativum cv. Avola) to arbuscular mycorrhizal fungi (AM) species Glomus mosseae and Glomus intraradices and Rhizobium leguminosarum bv. viceae, strain D 293, regarding the growth, photosynthesis, nodulation and nitrogen fixation activity. Pea plants were grown in a glasshouse until the flowering stage (35 days), in 4 kg plastic pots using leached cinnamonic forest soil (Chromic Luvisols – FAO) at P levels 13.2 (P1) and 39.8 (P2) mg P/kg soil. The obtained results demonstrated that the dual inoculation of pea plants significantly increased the plant biomass, photosynthetic rate, nodulation, and nitrogen fixation activity in comparison with single inoculation with Rhizobium leguminosarum bv. viceae strain D 293. On the other hand, coinoculation significantly increased the total phosphorus content in plant tissue, acid phosphatase activity and percentage of root colonization. The effectiveness of coinoculation with Rhizobium leguminosarum and Glomus mosseae was higher at the low phosphorus level while the coinoculation with Glomus intraradices appeared to be the most effective at higher phosphorus level.

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Digalactosyldiacylglycerol Synthase Gene MtDGD1 Plays an Essential Role in Nodule Development and Nitrogen Fixation

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-11-18-0322-r ◽

2019 ◽

Vol 32 (9) ◽

pp. 1196-1209

Author(s):

Zaiyong Si ◽

Qianqian Yang ◽

Rongrong Liang ◽

Ling Chen ◽

Dasong Chen ◽

...

Keyword(s):

Nitrogen Fixation ◽

Essential Role ◽

Symbiotic Nitrogen Fixation ◽

Histochemical Staining ◽

Nodule Development ◽

Nodule Number ◽

Nitrogen Fixation Activity ◽

Fixation Activity ◽

Infected Cells ◽

Nodule Symbiosis

Little is known about the genes participating in digalactosyldiacylglycerol (DGDG) synthesis during nodule symbiosis. Here, we identified full-length MtDGD1, a synthase of DGDG, and characterized its effect on symbiotic nitrogen fixation in Medicago truncatula. Immunofluorescence and immunoelectron microscopy showed that MtDGD1 was located on the symbiosome membranes in the infected cells. β-Glucuronidase histochemical staining revealed that MtDGD1 was highly expressed in the infection zone of young nodules as well as in the whole mature nodules. Compared with the control, MtDGD1-RNA interference transgenic plants exhibited significant decreases in nodule number, symbiotic nitrogen fixation activity, and DGDG abundance in the nodules, as well as abnormal nodule and symbiosome development. Overexpression of MtDGD1 resulted in enhancement of nodule number and nitrogen fixation activity. In response to phosphorus starvation, the MtDGD1 expression level was substantially upregulated and the abundance of nonphospholipid DGDG was significantly increased in the roots and nodules, accompanied by corresponding decreases in the abundance of phospholipids such as phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol. Overall, our results indicate that DGD1 contributes to effective nodule organogenesis and nitrogen fixation by affecting the synthesis and content of DGDG during symbiosis.

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