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.

Overexpression of the StP5CS gene promotes nodulation and nitrogen fixation in vegetable soybean under drought stress

2019 ◽  
Author(s):  
X. X. Wang ◽  
F. . Gao ◽  
S. P. Yang ◽  
J. Y. Gai ◽  
Y. L. Zhu
Keyword(s):  
Nitrogen Fixation ◽  
Drought Stress ◽  
Symbiotic Nitrogen Fixation ◽  
Nodule Development ◽  
Vegetable Soybean ◽  
Wild Type ◽  
Total N ◽  
Transgenic Lines ◽  
Glycine Max L ◽  
Better Than

The StP5CS (GenBank accession number: JN606861) T6 homozygous transgenic lines (HTLs) of vegetable soybean [Glycine max (L.) Merrill] were grown using vermiculite pot culture to determine whether StP5CS overexpression would enhance nodulation and symbiotic nitrogen fixation (SNF) in two T6 HTLs (17W-1, 17W-2) under drought conditions. The growth performance, nodule development and seed weight of T6 HTLs were significantly better than those of wild type (WT) plants. The proline levels in various tissues of T6 HTLs were higher than WT plants. The concentrations of total ureide, total N, leghemoglobin (Lb) and the activity of glutamine synthetase (GS, EC 6.3.1.2) in the T6 HTLs were significantly increased. Moreover, the relative expression levels of five key nodulation- and SNF-associated genes (i.e., GmENOD40-1, GmENOD40-2, GmLba, GmGS1â1 and GmGS1â2) were significantly higher in T6 HTLs. In conclusion, overexpression of StP5CS enhances nodulation and SNF in transgenic vegetable soybean under drought stress conditions

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 Morphogenesis of root nodules in white clover. II. The effect of mutation in genes nod IJ of the microsymbiont upon the nodule structure

2014 ◽  
Vol 67 (1) ◽  
pp. 5-22
Author(s):  
Barbara Łotocka ◽  
Joanna Kopcińska ◽  
Władysław Golinowski
Keyword(s):  
White Clover ◽  
Rhizobium Leguminosarum ◽  
Root Nodules ◽  
Single Cells ◽  
Wild Strain ◽  
Root Hairs ◽  
Nodule Development ◽  
Wild Type ◽  
Delayed Reaction ◽  
Infection Threads

Morphogenesis of ineffective root nodules initiated on the roots of white clover 'Astra' by the <em>Rhizobium leguminosarum</em> biovar. <em>trifolii</em> strains ANU261 (Tn5 insertion in nod 1 gene) and ANU262 (Tn5 insertion in nod J gene) was investigated. Following changes were observed, as compared to the wild-type nodulation: the exaggerated, not delayed reaction of root hairs; the delay in nodulation with the number of nodules the same as in plants inoculated with a wild strain; the formation and organization of the nodule primordium not changed in comparison with the wild-type nodules; infection threads abnormally branched and diffusing with bacteria deprived of light zone and enriched with storage material; infected cells of bacteroidal tissue abnormally strongly osmiophilic and only slightly vacuolated; symbiosomes with very narrowed peribacteroidal space, subject to premature degradation; abnormal accumulation of starch in the nodule tissues; nodule development blocked at the stage of laterally situated meristem and single nodule bundle; inhibition of divisions in the meristem and vacuolation of its cells; the appearance of single cells with colonies of saprophytic rhizobia embedded in the fibrillar matrix in the old, degraded regions of the bacteroidal tissue.

Metabolite Regulation of Phosphenolpyruvate Carboxylase in Legume Root Nodules

1996 ◽  
Vol 23 (4) ◽  
pp. 413 ◽  
Author(s):  
KC Woo ◽  
S Xu
Keyword(s):  
Nitrogen Fixation ◽  
Glycine Max ◽  
Vigna Unguiculata ◽  
Symbiotic Nitrogen Fixation ◽  
Feedback Inhibition ◽  
Root Nodules ◽  
Psophocarpus Tetragonolobus ◽  
Glycine Max L ◽  
Fructose 1,6 Bisphosphate ◽  
Metabolite Regulation

The effects of metabolic activators and inhibitors on phosphoenolpyruvate carboxylase (PEPC) activity were examined at pH 7 in partially purified enzyme from nodules of soybean (Glycine max (L.) Merr.), Psophocarpus tetragonolobus DC. and Vigna unguiculata ssp. sesquipedalis (L.) Verdc. Glucose 6-phosphate, fructose 6-phosphate, glucose 1-phosphate, fructose 1-phosphate, fructose 1,6- bisphosphate and phosphoglycerate stimulated the activity about 2-fold at low (0.5 mM) but not saturating (2.5 mM) PEP concentration. Glc 6-P and fru 6-P were the most effective activators and they increased the affinity of the enzyme for PEP by 2-4-fold. The dicarboxylates, malate, succinate, malonate, 2-oxoglutarate and aspartate inhibited PEPC activity. Malate was the most inhibitory, and strongly inhibited PEPC activity even at saturating PEP concentration. The Ki values for malate were 0.3-0.4 mM for soybean and P. tetragonolobus. However, glc 6-P and fru 6-P alleviated maiate inhibition and increased the Ki values by 11- to 28-fold in these two species. We propose that glc 6-P (fru 6-P) activates PEPC in a feedforward regulation and protects it against feedback inhibition by malate and thus coordinates the supply of photosynthate availability with malate synthesis required by the bacteroids to support symbiotic nitrogen fixation in nodules.

scholarly journals Transcription Profiling of Soybean Nodulation by Bradyrhizobium japonicum

2008 ◽  
Vol 21 (5) ◽  
pp. 631-645 ◽  
Author(s):  
Laurent Brechenmacher ◽  
Moon-Young Kim ◽  
Marisol Benitez ◽  
Min Li ◽  
Trupti Joshi ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Bradyrhizobium Japonicum ◽  
Root Nodules ◽  
Expression Patterns ◽  
Root Hairs ◽  
Defense Responses ◽  
Nodule Development ◽  
Plant Defense Responses ◽  
Polymerase Chain ◽  
High Level

Legumes interact with nodulating bacteria that convert atmospheric nitrogen into ammonia for plant use. This nitrogen fixation takes place within root nodules that form after infection of root hairs by compatible rhizobia. Using cDNA microarrays, we monitored gene expression in soybean (Glycine max) inoculated with the nodulating bacterium Bradyrhizobium japonicum 4, 8, and 16 days after inoculation, timepoints that coincide with nodule development and the onset of nitrogen fixation. This experiment identified several thousand genes that were differentially expressed in response to B. japonicum inoculation. Expression of 27 genes was analyzed by quantitative reverse transcriptase-polymerase chain reaction, and their expression patterns mimicked the microarray results, confirming integrity of analyses. The microarray results suggest that B. japonicum reduces plant defense responses during nodule development. In addition, the data revealed a high level of regulatory complexity (transcriptional, post-transcriptional, translational, post-translational) that is likely essential for development of the symbiosis and adjustment to an altered nutritional status.

scholarly journals Genome-Wide Transcript Analysis of Bradyrhizobium japonicum Bacteroids in Soybean Root Nodules

2007 ◽  
Vol 20 (11) ◽  
pp. 1353-1363 ◽  
Author(s):  
Gabriella Pessi ◽  
Christian H. Ahrens ◽  
Hubert Rehrauer ◽  
Andrea Lindemann ◽  
Felix Hauser ◽  
...  
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Experimental Approach ◽  
Root Nodules ◽  
Nodule Development ◽  
Dependent Manner ◽  
Wild Type ◽  
In Planta ◽  
Soybean Root ◽  
Genome Wide ◽  
Transcript Profiles

The transcriptome of endosymbiotic Bradyrhizobium japonicum bacteroids was assessed, using RNA extracted from determinate soybean root nodules. Results were compared with the transcript profiles of B. japonicum cells grown in either aerobic or microaerobic culture. Microoxia is a known trigger for the induction of symbiotically relevant genes. In fact, one third of the genes induced in bacteroids at day 21 after inoculation are congruent with those up-regulated in culture by a decreased oxygen concentration. The other induced genes, however, may be regulated by cues other than oxygen limitation. Both groups of genes provide a rich source for the possible discovery of novel functions related to symbiosis. Samples taken at different timepoints in nodule development have led to the distinction of genes expressed early and late in bacteroids. The experimental approach applied here is also useful for B. japonicum mutant analyses. As an example, we compared the transcriptome of wild-type bacteroids with that of bacteroids formed by a mutant defective in the RNA polymerase transcription factor σ54. This led to a collection of hitherto unrecognized B. japonicum genes potentially transcribed in planta in a σ54-dependent manner.

scholarly journals A Convenient, Soil-Free Method for the Production of Root Nodules in Soybean to Study the Effects of Exogenous Additives

2018 ◽  
Author(s):  
Swarup Roy Choudhury ◽  
Sarah M. Johns ◽  
Sona Pandey
Keyword(s):  
Nitrogen Fixation ◽  
Biological Nitrogen Fixation ◽  
Root Nodules ◽  
Growth Conditions ◽  
Nodule Development ◽  
Nodule Formation ◽  
Legume Crop ◽  
Simple Protocol ◽  
Biological Nitrogen

Legumes develop root nodules that harbour&nbsp;endosymbiotic bacteria, rhizobia. These rhizobia convert nitrogen to ammonia by biological nitrogen fixation. A thorough understanding of the biological nitrogen fixation in legumes and its regulation is key to develop sustainable agriculture. It is well known that plant hormones affect nodule formation; however, most studies are limited to model legumes due to their suitability for in vitro, plate-based assays. Specifically, it is almost impossible to measure the effects of exogenous hormones or other additives during nodule development in crop legumes such as soybean as they have huge root system in soil. To circumvent this issue, the present research develops suitable media and growth conditions for efficient nodule development under in vitro, soil free conditions in an important legume crop, soybean. Moreover, we also evaluate the effects of all major phytohormones during soybean nodulation under identical conditions. This versatile, inexpensive, scalable and simple protocol provides several advantages over previously established methods. It is extremely time-and resource-efficient, does not require special training or equipment, and produces highly reproducible results. The approach is expandable to other large legumes as well as for other exogenous additives.

scholarly journals MtMOT1.2 is responsible for molybdate supply toMedicago truncatulanodules

2018 ◽  
Author(s):  
Patricia Gil-Díez ◽  
Manuel Tejada-Jiménez ◽  
Javier León-Mediavilla ◽  
Jiangqi Wen ◽  
Kirankumar S. Mysore ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Symbiotic Nitrogen Fixation ◽  
Nitrogenase Activity ◽  
Reductase Activity ◽  
Root Nodules ◽  
Loss Of Function ◽  
Intracellular Membrane ◽  
Wild Type ◽  
Endodermal Cells ◽  
Iron Molybdenum Cofactor

ABSTRACTSymbiotic nitrogen fixation in legume root nodules requires a steady supply of molybdenum for synthesis of the iron-molybdenum cofactor of nitrogenase. This nutrient has to be provided by the host plant from the soil, crossing several symplastically disconnected compartments through molybdate transporters, including members of the MOT1 family. MtMOT1.2 is aMedicago truncatulaMOT1 family member located in the endodermal cells in roots and nodules. Immunolocalization of a tagged MtMOT1.2 indicates that it is associated to the plasma membrane and to intracellular membrane systems, where it would be transporting molybdate towards the cytosol, as indicated in yeast transport assays. A loss-of-functionmot1.2-1mutant showed reduced growth compared to wild-type plants when nitrogen fixation was required, but not when nitrogen was provided as nitrate. While no effect on molybdenum-dependent nitrate reductase activity was observed, nitrogenase activity was severely affected, explaining the observed difference of growth depending on nitrogen source. This phenotype was the result of molybdate not reaching the nitrogen-fixing nodules, since genetic complementation with a wild-typeMtMOT1.2gene or molybdate-fortification of the nutrient solution, both restored wild-type levels of growth and nitrogenase activity. These results support a model in which MtMOT1.2 would mediate molybdate delivery by the vasculature into the nodules.

scholarly journals Expression Map for Genes Involved in Nitrogen and Carbon Metabolism in Alfalfa Root Nodules

1999 ◽  
Vol 12 (6) ◽  
pp. 526-535 ◽  
Author(s):  
Gian B. Trepp ◽  
Stephen J. Temple ◽  
Bruna Bucciarelli ◽  
Li Fang Shi ◽  
Carroll P. Vance
Keyword(s):  
Nitrogen Fixation ◽  
Glutamine Synthetase ◽  
Carbon Metabolism ◽  
Root Nodule ◽  
Root Nodules ◽  
Constitutive Expression ◽  
Nodule Development ◽  
Relative Distribution ◽  
Nitrogen Fixing ◽  
Alfalfa Root

During root nodule development several key genes involved in nitrogen fixation and assimilation exhibit enhanced levels of expression. However, little is known about the temporal and spatial distribution patterns of these transcripts. In a systematic study the transcripts for 13 of the essential enzymes involved in alfalfa (Medicago sativa) root nodule nitrogen and carbon metabolism were localized by in situ hybridization. A serial section approach allowed the construction of a map that reflects the relative distribution of these transcripts. In 33-day-old root nodules, the expression of nifH, NADH-dependent glutamate synthase (NADH-GOGAT; EC 1.4.1.14) and a cytosolic isoform of glutamine synthetase (GS13; GS; EC 6.3.1.2) were localized predominantly in a 5- to 15-cell-wide region in the distal part of the nitrogen-fixing zone. This zone was also the region of high expression for leghemoglobin, a second cytosolic glutamine synthetase isoform (GS100), aspartate aminotransferase-2 (AAT-2; EC 2.6.1.1), asparagine synthetase (AS; 6.3.5.4), phosphoenolpyruvate carboxylase (PEPC; EC 4.1.1.31), and sucrose synthase (SuSy; EC 2.4.1.13). This suggests that, in 33-day-old alfalfa root nodules, nitrogen fixation is restricted to this 5- to 15-cell-wide area. The continued significant expression of the GS100 subclass of GS and AS in the proximal part of the nitrogen-fixing zone implicates these gene products in nitrogen remobilization. A low constitutive expression of NADH-dependent glutamate dehydrogenase (NADH-GDH; EC 1.4.1.2) was observed throughout the nodule. The transcript distribution map will be used as a navigational tool to assist in developing strategies for the genetic engineering of alfalfa root nodules for enhanced nitrogen assimilation.

scholarly journals A toolbox for nodule development studies in chickpea: a hairy-root transformation protocol and an efficient laboratory strain of Mesorhizobium sp

2018 ◽  
Author(s):  
Drishti Mandal ◽  
Senjuti Sinharoy
Keyword(s):  
Nitrogen Fixation ◽  
Hairy Root ◽  
Root Nodules ◽  
Laboratory Strain ◽  
Nodule Development ◽  
Model Legume ◽  
Transformation Protocol ◽  
Evolutionary Diversification ◽  
Fluorescent Markers ◽  
Root Transformation

AbstractMesorhizobium sp. produces root nodules in chickpea. Chickpea and model legume Medicago truncatula are members of inverted repeat lacking clade (IRLC). The rhizobia after internalization inside plant cell called ‘bacteroid’. Nodule Specific Cysteine-rich (NCR) peptides in IRLC legumes guide bacteroids to a ‘terminally differentiated swollen (TDS)’ form. Bacteroids in chickpea are less TDS than those in Medicago. Nodule development in chickpea indicates recent evolutionary diversification and merits further study. A hairy root transformation protocol and an efficient laboratory strain are prerequisites for performing any genetic study on nodulation. We have standardized a protocol for composite plant generation in chickpea with a transformation frequency above 50%, as shown by fluorescent markers. This protocol also works well in different ecotypes of chickpea. Localization of subcellular markers in these transformed roots is similar to Medicago. When checked inside transformed nodules, peroxisomes were concentrated along the periphery of the nodules, while ER and golgi bodies surrounded the symbiosomes. Different Mesorhizobium strains were evaluated for their ability to initiate nodule development, and efficiency of nitrogen fixation. Inoculation with different strains resulted in different shapes of TDS bacteroids with variable nitrogen fixation. Our study provides a toolbox to study nodule development in the crop legume chickpea.

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