Histological and ultrastructural observations of Medicago sativa root nodule senescence after foliage removal

1980 ◽  
Vol 58 (3) ◽  
pp. 295-309 ◽  
Author(s):  
C. P. Vance ◽  
L. E. B. Johnson ◽  
A. M. Halvorsen ◽  
G. H. Heichel ◽  
D. K. Barnes
Keyword(s):  
Medicago Sativa ◽  
Root Nodule ◽  
Root Nodules ◽  
Degenerative Changes ◽  
Vascular Bundles ◽  
Nodule Senescence ◽  
Infection Threads ◽  
Medicago Sativa L ◽  
Cellular Integrity ◽  
And Control

Root nodules from control and defoliated alfalfa (Medicago sativa L.) were compared for a period of 18 days following defoliation. Bacteroid containing cells of the nodules decreased markedly for the first 10 days following defoliation, but then increased during the next 8 days. Nodule length increased continuously during the 18 days in both control and defoliated plants. Cellular integrity of vascular bundles, meristems, and infection threads was retained in nodules from treated and control plants throughout the experiment. The sequence of senescence in bacteroid containing cells was similar in nodules from both treatments. Senescence was initially observed in the cytoplasm of bacteroid containing cells. Membranes surrounding bacteroids showed degenerative changes as bacteroids senesced. Bacteroids aggregated within nodule cells. Infection threads and bacteria inside infection threads did not disintegrate. Bacteroids ultimately disappeared in senescent cells.Nodules of alfalfa appear to respond to foliar harvesting by a partial but temporary senescence from which they recover by regeneration of bacteroid containing cells.

scholarly journals Expression Analysis of PIN Genes in Root Tips and Nodules of Lotus japonicus

2019 ◽  
Vol 20 (2) ◽  
pp. 235 ◽  
Author(s):  
Izabela Sańko-Sawczenko ◽  
Dominika Dmitruk ◽  
Barbara Łotocka ◽  
Elżbieta Różańska ◽  
Weronika Czarnocka
Keyword(s):  
Root Nodule ◽  
Root Nodules ◽  
Quantitative Polymerase Chain Reaction ◽  
Lotus Japonicus ◽  
Nodule Development ◽  
Vascular Bundles ◽  
Root Tips ◽  
Gus Reporter ◽  
Gene Assay ◽  
Development And Differentiation

Auxins are postulated to be one of the pivotal factors in nodulation. However, their transporters in Lotus japonicus, the model species for the study of the development of determinate-type root nodules, have been scarcely described so far, and thus their role in nodulation has remained unknown. Our research is the first focusing on polar auxin transporters in L. japonicus. We analyzed and compared expression of PINs in 20 days post rhizobial inoculation (dpi) and 54 dpi root nodules of L. japonicus by real-time quantitative polymerase chain reaction (qPCR) along with the histochemical β-glucuronidase (GUS) reporter gene assay in transgenic hairy roots. The results indicate that LjPINs are essential during root nodule development since they are predominantly expressed in the primordia and young, developing nodules. However, along with differentiation, expression levels of several PINs decreased and occurred particularly in the nodule vascular bundles, especially in connection with the root’s stele. Moreover, our study demonstrated the importance of both polar auxin transport and auxin intracellular homeostasis during L. japonicus root nodule development and differentiation.

Electron microscopic observations of infection threads in driselase treated nodules of Astragalus sinicus

1986 ◽  
Vol 32 (12) ◽  
pp. 947-952 ◽  
Author(s):  
Shiro Higashi ◽  
Kazuya Kushiyama ◽  
Mikiko Abe
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Root Nodules ◽  
Morphological Characteristics ◽  
Enzyme Treatment ◽  
Vascular Bundles ◽  
Electron Microscopic ◽  
Astragalus Sinicus ◽  
Infection Threads

The morphological characteristics of infection threads in the root nodules of Astragalus sinicus were examined by scanning and transmission electron microscopy. The infection threads, epidermal cell walls, and vascular bundles of the nodule were not altered when a nodule was treated with driselase (a plant cell wall degrading enzyme), although the cell walls of meristematic and bacteroid-including zones were completely decomposed by the enzyme treatment. Some infection threads were funnel shaped at the site of attachment of the infection thread to the host cell wall.

scholarly journals Localization of acid phosphatase activity in the apoplast of root nodules of pea (Pisum sativum)

2011 ◽  
Vol 75 (1) ◽  
pp. 33-38 ◽  
Author(s):  
Marzena Sujkowska ◽  
Wojciech Borucki ◽  
Władysław Golinowski
Keyword(s):  
Enzyme Activity ◽  
Acid Phosphatase ◽  
Pisum Sativum ◽  
Root Nodule ◽  
Root Nodules ◽  
Outer Part ◽  
Inorganic Phosphorus ◽  
Infection Thread ◽  
Symbiotic Bacteria ◽  
Infection Threads

Changes in the activity of acid phosphatase (AcPase) in the apoplast of pea root nodule were investigated. The activity was determined using lead and cerium methods. The results indicated a following sequence of AcPase activity appearance during the development of the infection thread: 1) low AcPase activity appears in the outer part of cells of symbiotic bacteria; 2) bacteria show increased AcPase activity, and the enzyme activity appears in the thread walls; 3) activity exhibits also matrix of the infection thread; 4) bacteria just before their release from the infection threads show high AcPase activity; 5) AcPase activity ceases after bacteria transformation into bacteroids. The increase in bacterial AcPase activity may reflect a higher demand for inorganic phosphorus necessary for propagation of the bacteria within the infection threads and/or involved in bacteria release from the infection threads.

scholarly journals The Alfalfa (Medicago sativa) TDY1 Gene Encodes a Mitogen-Activated Protein Kinase Homolog

1999 ◽  
Vol 12 (10) ◽  
pp. 882-893 ◽  
Author(s):  
Mark A. Schoenbeck ◽  
Deborah A. Samac ◽  
Maria Fedorova ◽  
Robert G. Gregerson ◽  
J. Stephen Gantt ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Medicago Sativa ◽  
Map Kinases ◽  
Root Nodules ◽  
Genomic Clone ◽  
Mitogen Activated Protein Kinase ◽  
Vascular Bundles ◽  
Root Tips ◽  
Pathogen Invasion ◽  
Mitogen Activated Protein

Development of root nodules, specifically induction of cortical cell division for nodule initiation, requires expression of specific genes in the host and microsymbiont. A full-length cDNA clone and the corresponding genomic clone encoding a MAP (mitogen-activated protein) kinase homolog were isolated from alfalfa (Medicago sativa). The genomic clone, TDY1, encodes a 68.9-kDa protein with 47.7% identity to MMK4, a previously characterized MAP kinase homolog from alfalfa. TDY1 is unique among the known plant MAP kinases, primarily due to a 230 amino acid C-terminal domain. The putative activation motif, Thr-Asp-Tyr (TDY), also differs from the previously reported Thr-Glu-Tyr (TEY) motif in plant MAP kinases. TDY1 messages were found predominantly in root nodules, roots, and root tips. Transgenic alfalfa and Medicago truncatula containing a chimeric gene consisting of 1.8 kbp of 5′ flanking sequence of the TDY1 gene fused to the β-glucuronidase (GUS) coding sequence exhibited GUS expression primarily in the nodule parenchyma, meristem, and vascular bundles, root tips, and root vascular bundles. Stem internodes stained intensely in cortical parenchyma, cambial cells, and primary xylem. GUS activity was observed in leaf mesophyll surrounding areas of mechanical wounding and pathogen invasion. The promoter was also active in root tips and apical meristems of transgenic tobacco. Expression patterns suggest a possible role for TDY1 in initiation and development of nodules and roots, and in localized responses to wounding.

Plant determined ineffective nodules in alfalfa (Medicago sativa): structural and biochemical comparisons

1983 ◽  
Vol 61 (1) ◽  
pp. 93-106 ◽  
Author(s):  
C. P. Vance ◽  
L. E. B. Johnson
Keyword(s):  
Medicago Sativa ◽  
Phosphoenolpyruvate Carboxylase ◽  
Soluble Protein ◽  
Biochemical Parameters ◽  
Glutamate Synthase ◽  
Host Cells ◽  
Ammonia Assimilation ◽  
Infection Threads ◽  
Medicago Sativa L ◽  
Enzymes Of Ammonia Assimilation

Nodule structure, nodule enzymes of ammonia assimilation, nodule phosphoenolpyruvate carboxylase, nitrogenase-dependent acetylene reduction, and soluble protein were studied in four plant-determined ineffective genotypes and in one effective genotype of alfalfa (Medicago sativa L.) grown in a glasshouse. Ineffective nodules that formed on genotypes MnAg(In) and MnSa(In) were similar to effective nodules in early development. However, these nodules had smaller bacteroids and senesced much more rapidly than effective nodules. In contrast, nodules that formed on ineffective genotypes MnNC-3226(In) and MnNC-3811(In) were tumorlike and had few infection threads and bacteroids, and host cells were filled with starch. Nodules from plant-determined ineffective genotypes had reduced glutamine synthetase, glutamate synthase, phosphoenolpyruvate carboxylase, and nodule soluble protein when compared with effective nodules. There were differences between genotypes for all biochemical parameters assayed.

Diverse bacterial taxa inhabit root nodules of lucerne (Medicago sativa L.) in New Zealand pastoral soils

2017 ◽  
Vol 420 (1-2) ◽  
pp. 253-262 ◽  
Author(s):  
Kathryn Wigley ◽  
Derrick Moot ◽  
Steve A Wakelin ◽  
Aurelie Laugraud ◽  
Celine Blond ◽  
...  
Keyword(s):  
New Zealand ◽  
Medicago Sativa ◽  
Root Nodules ◽  
Medicago Sativa L

scholarly journals Asparagine Biosynthesis in Alfalfa (Medicago sativa L.) Root Nodules

1986 ◽  
Vol 82 (2) ◽  
pp. 390-395 ◽  
Author(s):  
Sieglinde S. Snapp ◽  
Carroll P. Vance
Keyword(s):  
Medicago Sativa ◽  
Root Nodules ◽  
Medicago Sativa L
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