scholarly journals Critical role for uricase and xanthine dehydrogenase in soybean nitrogen fixation and nodule development

2021 ◽  
Author(s):  
Cuong X. Nguyen ◽  
Alice Dohnalkova ◽  
C. Nathan Hancock ◽  
Kendall R. Kirk ◽  
Gary Stacey ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Critical Role ◽  
Xanthine Dehydrogenase ◽  
Nodule Development

scholarly journals Chickpea shows genotype-specific nodulation responses across soil nitrogen environment and root disease resistance categories

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Krista L. Plett ◽  
Sean L. Bithell ◽  
Adrian Dando ◽  
Jonathan M. Plett
Keyword(s):  
Nitrogen Fixation ◽  
Disease Resistance ◽  
Soil Nitrogen ◽  
Cellular Localization ◽  
Expression Patterns ◽  
Nodule Development ◽  
Nodule Formation ◽  
Symbiotic Relationship ◽  
Plant Genotype ◽  
Factors Affecting

Abstract Background The ability of chickpea to obtain sufficient nitrogen via its symbiotic relationship with Mesorhizobium ciceri is of critical importance in supporting growth and grain production. A number of factors can affect this symbiotic relationship including abiotic conditions, plant genotype, and disruptions to host signalling/perception networks. In order to support improved nodule formation in chickpea, we investigated how plant genotype and soil nutrient availability affect chickpea nodule formation and nitrogen fixation. Further, using transcriptomic profiling, we sought to identify gene expression patterns that characterize highly nodulated genotypes. Results A study involving six chickpea varieties demonstrated large genotype by soil nitrogen interaction effects on nodulation and further identified agronomic traits of genotypes (such as shoot weight) associated with high nodulation. We broadened our scope to consider 29 varieties and breeding lines to examine the relationship between soilborne disease resistance and the number of nodules developed and real-time nitrogen fixation. Results of this larger study supported the earlier genotype specific findings, however, disease resistance did not explain differences in nodulation across genotypes. Transcriptional profiling of six chickpea genotypes indicates that genes associated with signalling, N transport and cellular localization, as opposed to genes associated with the classical nodulation pathway, are more likely to predict whether a given genotype will exhibit high levels of nodule formation. Conclusions This research identified a number of key abiotic and genetic factors affecting chickpea nodule development and nitrogen fixation. These findings indicate that an improved understanding of genotype-specific factors affecting chickpea nodule induction and function are key research areas necessary to improving the benefits of rhizobial symbiosis in chickpea.

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

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.

Comparative nodulation, nitrogen fixation, and growth of Glycine wightii cv. Cooper and Phaseolus atropurpureus cv. Siratro seedlings

1972 ◽  
Vol 23 (1) ◽  
pp. 1 ◽  
Author(s):  
JR Wilson
Keyword(s):  
Nitrogen Fixation ◽  
Full Range ◽  
Sand Culture ◽  
Nodule Development ◽  
Nitrogen Accumulation ◽  
Active Nitrogen ◽  
Plant Weight ◽  
Culture Techniques ◽  
Whole Plant ◽  
Seed Reserves

The growth, nodulation, and nitrogen fixation of Glycine wightii cv. Cooper (Glycine) and Phaseolus atropurpureus cv. Siratro (Siratro) were compared in a glasshouse, sand culture techniques being used in a series of trials encompassing a full range of seasonal environments. Plants were inoculated with the commercial Rhizobium strain (CB756) for both species either at germination or 12 days later when seed reserves were virtually exhausted. In both early and late inoculation treatments, Siratro nodulated and established nitrogen fixation more rapidly than did Glycine. This difference between the species was not directly associated with the marked difference in seed size. When active nitrogen fixation was fully established, the disadvantage shown by Glycine in the early nodulation phase was not evident, and the treatments were similar in the rate of growth and nitrogen accumulation, proportion of nodule weight to whole plant weight, proportion of pigmented nodules, efficiency of nitrogen fixation, and concentration of nitrogen in the whole plant. The relatively slow initial nodule development in Glycine is probably one of the important factors hindering the field establishment of seedlings, but in subsequent growth the symbiosis appears fully effective.

scholarly journals Phosphorus Scavenging in the Unicellular Marine Diazotroph Crocosphaera watsonii

2006 ◽  
Vol 72 (2) ◽  
pp. 1452-1458 ◽  
Author(s):  
Sonya T. Dyhrman ◽  
Sheean T. Haley
Keyword(s):  
Nitrogen Fixation ◽  
Critical Role ◽  
Sole Source ◽  
Phosphate Transport ◽  
Phosphate Binding ◽  
High Affinity ◽  
Tropical Environments ◽  
The Pacific ◽  
The Many ◽  
Crocosphaera Watsonii

ABSTRACT Through the fixation of atmospheric nitrogen and photosynthesis, marine diazotrophs play a critical role in the global cycling of nitrogen and carbon. Crocosphaera watsonii is a recently described unicellular diazotroph that may significantly contribute to marine nitrogen fixation in tropical environments. One of the many factors that can constrain the growth and nitrogen fixation rates of marine diazotrophs is phosphorus bioavailability. Using genomic and physiological approaches, we examined phosphorus scavenging mechanisms in strains of C. watsonii from both the Atlantic and the Pacific. Observations from the C. watsonii WH8501 genome suggest that this organism has the capacity for high-affinity phosphate transport (e.g., homologs of pstSCAB) in low-phosphate, oligotrophic systems. The pstS gene (high-affinity phosphate binding) is present in strains isolated from both the Atlantic and the Pacific, and its expression was regulated by the exogenous phosphate supply in strain WH8501. Genomic observation also indicated a broad capacity for phosphomonoester hydrolysis (e.g., a putative alkaline phosphatase). In contrast, no clear homologs of genes for phosphonate transport and hydrolysis could be identified. Consistent with these genomic observations, C. watsonii WH8501 is able to grow on phosphomonoesters as a sole source of added phosphorus but not on the phosphonates tested to date. Taken together these data suggest that C. watsonii has a robust capacity for scavenging phosphorus in oligotrophic systems, although this capacity differs from that of other marine cyanobacterial genera, such as Synechococcus, Prochlorococcus, and Trichodesmium.

Starch content and activities of starch-metabolizing enzymes in effective and ineffective root nodules of soybean

1991 ◽  
Vol 69 (4) ◽  
pp. 697-701 ◽  
Author(s):  
Sharon I. Forrest ◽  
Desh Pal S. Verma ◽  
Rajinder S. Dhindsa
Keyword(s):  
Nitrogen Fixation ◽  
Starch Content ◽  
Root Nodules ◽  
Starch Synthase ◽  
Nodule Development ◽  
Wild Type ◽  
Starch Phosphorylase ◽  
High Concentration ◽  
Key Words Nitrogen Fixation ◽  
Glycine Max L

Starch content and activities of some enzymes of starch metabolism were determined in wild-type, N2-fixing (fix+) nodules and in two non-N2-fixing (fix−) nodules induced by Bradyrhizobium japonicum mutant strains, T5-95 and T8-1, on soybean (Glycine max L.) roots. The T5-95 nodules are similar to wild type in ultrastructure, but the T8-1 nodules are different in that the bacteroids are not released from the infection thread. After initial accumulation to relatively high concentration, starch was depleted during nitrogen fixation in fix+ nodules. However, in fix− nodules, the accumulated starch was not metabolized. The activity of starch-bound starch synthase (EC 2.4.1.21) declined in fix+ nodules but remained high in fix− nodules. The activity of α-amylase (EC 3.2.1.1) was only slightly higher than wild type in T5-95 but was four times higher than wild type in T8-1 nodules. The activity of starch phosphorylase (EC 2.4.1.1) increased in all nodule types from 14 to 21 days postinfection. A positive correlation was observed between the capacity of nodules to fix N2 and their capacity to degrade starch. Collectively, these results support the concept that starch accumulated during early stages of nodule development is metabolized to supply energy for nitrogen fixation and to meet the metabolic demands of bacteroids. Key words: nitrogen fixation, starch content, effective and ineffective nodules, starch synthase, starch phosphorylase, α-amylase.

scholarly journals Aspartate Aminotransferase in Alfalfa Nodules: Localization of mRNA During Effective and Ineffective Nodule Development and Promoter Analysis

1999 ◽  
Vol 12 (4) ◽  
pp. 263-274 ◽  
Author(s):  
Hirofumi Yoshioka ◽  
Robert G. Gregerson ◽  
Deborah A. Samac ◽  
Kim C. M. Hoevens ◽  
Gian Trepp ◽  
...  
Keyword(s):  
Aspartate Aminotransferase ◽  
Root Nodules ◽  
Critical Role ◽  
Nodule Development ◽  
Vascular Bundles ◽  
Fixed Nitrogen ◽  
Transcript Accumulation ◽  
Specific Expression ◽  
Promoter Deletion Analysis

Aspartate aminotransferase (AAT) plays a critical role in the assimilation of symbiotically fixed nitrogen into aspartate and asparagine in legume root nodules. The enzyme occurs as a cytosolic form (AAT1) and a plastid form (AAT2) in alfalfa nodules. To elucidate the functional role of each isozyme in root nodule metabolism further, in situ hybridization was used to determine the pattern of transcript accumulation from the two genes. AAT2 transcripts were localized to infected cells throughout the symbiotic zone of effective alfalfa nodules; however, expression was reduced in ineffective nodules. The AAT1 gene was expressed in the uninfected cells of the invasion zone and symbiotic zone, the nodule parenchyma, and nodule vascular bundles of both effective and ineffective nodules. The AAT1 and AAT2 promoters were evaluated in transgenic alfalfa plants containing promoter β-glucuronidase (GUS) gene fusions. Histochemical staining patterns agreed with results from in situ localization. The distribution pattern of gene transcripts suggests that AAT1 has a role in maintenance of the O2 diffusion barrier in nodules and that AAT2 plays a major role in assimilation of recently fixed nitrogen. Promoter deletion analysis of the AAT2 promoter revealed that nodule-specific expression was retained in a promoter fragment of 300 bp.

scholarly journals Absence of Symbiotic Leghemoglobins Alters Bacteroid and Plant Cell Differentiation During Development of Lotus japonicus Root Nodules

2009 ◽  
Vol 22 (7) ◽  
pp. 800-808 ◽  
Author(s):  
Thomas Ott ◽  
John Sullivan ◽  
Euan K. James ◽  
Emmanouil Flemetakis ◽  
Catrin Günther ◽  
...  
Keyword(s):  
Gene Expression ◽  
Nitrogen Fixation ◽  
Cell Differentiation ◽  
Root Nodules ◽  
Lotus Japonicus ◽  
Nodule Development ◽  
Primary And Secondary Metabolism ◽  
Bacterial Differentiation ◽  
Plant Genes ◽  
Bacterial Genes

During development of legume root nodules, rhizobia and their host plant cells undergo profound differentiation, which is underpinned by massive changes in gene expression in both symbiotic partners. Oxygen concentrations in infected and surrounding uninfected cells drop precipitously during nodule development. To assess what effects this has on plant and bacterial cell differentiation and gene expression, we used a leghemoglobin-RNA-interference (LbRNAi) line of Lotus japonicus, which is devoid of leghemoglobins and has elevated levels of free-oxygen in its nodules. Bacteroids in LbRNAi nodules showed altered ultrastructure indicating changes in bacterial differentiation. Transcript analysis of 189 plant and 192 bacterial genes uncovered many genes in both the plant and bacteria that were differentially regulated during nodulation of LbRNAi plants compared with the wild type (containing Lb and able to fix nitrogen). These included fix and nif genes of the bacteria, which are involved in microaerobic respiration and nitrogen fixation, respectively, and plant genes involved in primary and secondary metabolism. Metabolite analysis revealed decreased levels of many amino acids in nodules of LbRNAi plants, consistent with the defect in symbiotic nitrogen fixation of this line.

scholarly journals Induction and Spatial Organization of Polyamine Biosynthesis During Nodule Development in Lotus japonicus

2004 ◽  
Vol 17 (12) ◽  
pp. 1283-1293 ◽  
Author(s):  
Emmanouil Flemetakis ◽  
Rodica C. Efrose ◽  
Guilhem Desbrosses ◽  
Maria Dimou ◽  
Costas Delis ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Symbiotic Nitrogen Fixation ◽  
Expression Patterns ◽  
Lotus Japonicus ◽  
Cyclin D3 ◽  
Nodule Development ◽  
Cdna Clones ◽  
Long Distance ◽  
Polyamine Biosynthesis ◽  
Transcript Levels

Putrescine and other polyamines are produced by two alternative pathways in plants. One pathway starts with the enzyme arginine decarboxylase (ADC; EC 4.1.1.19), the other with ornithine decarboxylase (ODC; EC 4.1.1.17). Metabolite profiling of nitrogen-fixing Lotus japonicus nodules, using gas chromatography coupled to mass spectrometry, revealed a two- to sixfold increase in putrescine levels in mature nodules compared with other organs. Genes involved in polyamine biosynthesis in L. japonicus nodules were identified by isolating cDNA clones encoding ADC (LjADC1) and ODC (LjODC) from a nodule library. Searches of the public expressed sequence tag databases revealed the presence of a second gene encoding ADC (LjADC2). Real-time reverse-transcription-polymerase chain reaction analysis showed that LjADC1 and LjADC2 were expressed throughout the plant, while LjODC transcripts were detected only in nodules and roots. Induction of LjODC and LjADC gene expression during nodule development preceded symbiotic nitrogen fixation. Transcripts accumulation was maximal at 10 days postinfection, when a 6.5-fold increase in the transcript levels of LjODC was observed in comparison with the uninfected roots, while a twofold increase in the transcript levels of LjADC1 and LjADC2 was detected. At later stages of nodule development, transcripts for ADC drastically declined, while in the case of ODC, transcript accumulation was higher than that in roots until after 21 days postinfection. The expression profile of genes involved in putrescine biosynthesis correlated well with the expression patterns of genes involved in cell division and expansion, including a L. japonicus Cyclin D3 and an α-expansin gene. Spatial localization of LjODC and LjADC1 gene transcripts in developing nodules revealed that both transcripts were expressed in nodule inner cortical cells and in the central tissue. High levels of LjADC1 transcripts were also observed in both nodule and connecting root vascular tissue, suggesting that putrescine and other polyamines may be subject to long-distance transport. Our results indicate that polyamines are primarily involved in physiological and cellular processes involved in nodule development, rather than in processes that support directly symbiotic nitrogen fixation and assimilation.

scholarly journals EVALUATION OF SEVERAL GROWING MEDIA FOR USE IN NITROGEN FIXATION RESEARCH

HortScience ◽  
1992 ◽  
Vol 27 (11) ◽  
pp. 1166b-1166
Author(s):  
Stephanie Rademan ◽  
Dyremple Marsh
Keyword(s):  
Nitrogen Fixation ◽  
Seed Coat ◽  
Germination Rate ◽  
Dry Weight ◽  
Kidney Bean ◽  
Nodule Development ◽  
Growing Media ◽  
Shoot Dry Weight ◽  
Gm Plants ◽  
Wide Range

A wide range of methodologies, ranging from Leonard jar to growth pouch have been used to investigate the nitrogen fixation process in leguminous crops. The effectiveness of most of these research methods have been questioned. Problems encountered vary from difficulty in root separation to water log conditions. This study was undertaken to determine the effect of different growing media on nodule development and harvestability. Black and Red seed coat kidney bean were surface sterilized and inoculated with the Rhizobium phaseoli strain UMR 1899. Seeds were planted in 8.5 cm diameter sterile clay pots containing the respective growing medium. These growing media were sand, Promix GM, Promix BX, and fritted clay. The black seed coat kidney bean had higher germination rate under all media for all dates recorded. Black kidney bean grown in sand and fritted clay had plant heights significantly greater than ones grown in the other media on the third harvest date. Nodule activities as measured by shoot dry weight and nodule number were significantly higher in both beans grown in fritted clay than in other media. Promix GM plants with dry weight of .45g for the black bean and .32g for the red beans were the lowest. Nodule separation from the growing media was easiest when plants were grown in sand, however, this was not significantly different from that of plants grown in fritted clay.

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