Cytokinin production in relation to the development of pea root nodules

1976 ◽  
Vol 54 (18) ◽  
pp. 2155-2162 ◽  
Author(s):  
Kunihiko Syōno ◽  
William Newcomb ◽  
John G. Torrey
Keyword(s):  
Growth Rate ◽  
Pisum Sativum ◽  
Mitotic Activity ◽  
Rhizobium Leguminosarum ◽  
Root Nodules ◽  
Lateral Roots ◽  
Cytokinin Activity ◽  
Garden Pea ◽  
Meristematic Cells ◽  
Quantitative Changes

Quantitative changes in cytokinins were examined in developing root nodules on the lateral roots of seedlings of the garden pea Pisum sativum cv. Little Marvel infected with Rhizobium leguminosarum strain 128 C53.Cytokinin activity was highest in 2- and 3-week-old nodules, when the growth rate was high, and decreased in older nodules. The cytokinin activities of 3-week-old nodules of various sizes were positively correlated with mitotic indices. In 3- and 4-week-old nodules most of the cytokinins were present in the white meristematic tip and not in the infected nitrogen-fixing or senescent cells. Since high cytokinin levels were associated with nodules having high mitotic rates or with the meristematic cells, it is proposed that cytokinins influence nodule morphogenesis by regulating the mitotic activity of the nodule meristem.

A correlated light and electron microscopic study of symbiotic growth and differentiation in Pisum sativum root nodules

1976 ◽  
Vol 54 (18) ◽  
pp. 2163-2186 ◽  
Author(s):  
William Newcomb
Keyword(s):  
Electron Microscopy ◽  
Pisum Sativum ◽  
Rhizobium Leguminosarum ◽  
Root Nodules ◽  
Light And Electron Microscopy ◽  
Infection Thread ◽  
Electron Microscopic ◽  
Cortical Cells ◽  
Garden Pea ◽  
Host Cytoplasm

Plants of the garden pea Pisum sativum cv. Little Marvel were grown in aeroponic culture to facilitate observations and microscopy and were inoculated with Rhizobium leguminosarum, and nodules were sampled at five weekly intervals for light and electron microscopy. The invasion of the cortical cells by the infection thread, the structure of the infection thread, and the release of bacteria from it into the host cytoplasm and the subsequent symbiotic growth and differentiation of the two organisms are described in detail. The fine structure of the nodule is correlated with light microscopic observations and morphogenesis. A restriction in the use of the term 'vesicle' is proposed because of the current multiple and confusing usage of the term. The loss of the nodule meristem and its morphogenetic significance are discussed.

scholarly journals NodC-based evaluation of the occurrence of bacteria in nodules of Pisum sativum isolated on YEM agar

2019 ◽  
Vol 70 (1) ◽  
pp. 59-67
Author(s):  
Anna Lenart-Boroń ◽  
Tadeusz Zając ◽  
Piotr Mateusz Boroń ◽  
Agnieszka Klimek-Kopyra
Keyword(s):  
Pisum Sativum ◽  
Rhizobium Leguminosarum ◽  
Reference Strain ◽  
Root Nodules ◽  
Bacterial Species ◽  
Soil Science ◽  
Associated Bacteria ◽  
Plant Cultivation ◽  
Yeast Extract Mannitol ◽  
Diverse Community

SummaryThe bacterial nodulation (nod) genes are essential in the formation process of root nodules. This study was aimed to verify the occurrence of nodule-associated bacteria in two pea varieties (“Tarchalska” and “Klif ”) inoculated withRhizobiuminoculants – Nitragine™ and a noncommercial one produced by the Polish Institute of Soil Science and Plant Cultivation (IUNG). The number of colonies isolated on yeast extract mannitol (YEM) agar from the nodules of “Klif ” inoculated with IUNG inoculants was significantly higher than the number of colonies isolated from other variants. Species identification was based on sequencing of 16S rDNA, which revealed that despite careful sterilization of nodules, sequences of other bacterial species were detected. Among them, one sequence belonged toRhizobium leguminosarum(isolated from IUNG inoculant). To assess the presence of nodulation-capableRhizobium, amplification of thenodCgene was performed, which revealed that of 29 samples, 19 were positive. The remaining isolates, including reference strain and bacteria isolated from Nitragine™, lacked this gene. The results show that pea nodules harbor a very diverse community of bacteria. The lack ofnodCgene in some strains isolated from plants inoculated with Nitragine™ and with IUNG inoculant proves that even ifR. leguminosarumare abundant, they may not be efficient in nodulation.

scholarly journals Heterologous Complementation Reveals a Specialized Activity for BacA in the Medicago–Sinorhizobium meliloti Symbiosis

2017 ◽  
Vol 30 (4) ◽  
pp. 312-324 ◽  
Author(s):  
George C. diCenzo ◽  
Maryam Zamani ◽  
Hannah N. Ludwig ◽  
Turlough M. Finan
Keyword(s):  
Pisum Sativum ◽  
Sinorhizobium Meliloti ◽  
Rhizobium Leguminosarum ◽  
Root Nodules ◽  
Specific Interaction ◽  
Model System ◽  
Single Model ◽  
Leguminous Plants ◽  
Melilotus Alba ◽  
Developmental Progression

The bacterium Sinorhizobium meliloti Rm2011 forms N2-fixing root nodules on alfalfa and other leguminous plants. The pSymB chromid contains a 110-kb region (the ETR region) showing high synteny to a chromosomally located region in Sinorhizobium fredii NGR234 and related rhizobia. We recently introduced the ETR region from S. fredii NGR234 into the S. meliloti chromosome. Here, we report that, unexpectedly, the S. fredii NGR234 ETR region did not complement deletion of the S. meliloti ETR region in symbiosis with Medicago sativa. This phenotype was due to the bacA gene of NGR234 not being functionally interchangeable with the S. meliloti bacA gene during M. sativa symbiosis. Further analysis revealed that, whereas bacA genes from S. fredii or Rhizobium leguminosarum bv. viciae 3841 failed to complement the Fix− phenotype of a S. meliloti bacA mutant with M. sativa, they allowed for further developmental progression prior to a loss of viability. In contrast, with Melilotus alba, bacA from S. fredii and R. leguminosarum supported N2 fixation by a S. meliloti bacA mutant. Additionally, the S. meliloti bacA gene can support N2 fixation of a R. leguminosarum bacA mutant during symbiosis with Pisum sativum. A phylogeny of BacA proteins illustrated that S. meliloti BacA has rapidly diverged from most rhizobia and has converged toward the sequence of pathogenic genera Brucella and Escherichia. These data suggest that the S. meliloti BacA has evolved toward a specific interaction with Medicago and highlights the limitations of using a single model system for the study of complex biological topics.

The occurrence and ontogeny of transfer cells associated with lateral roots and root nodules in Leguminosae

1979 ◽  
Vol 57 (23) ◽  
pp. 2583-2602 ◽  
Author(s):  
William Newcomb ◽  
R. L. Peterson
Keyword(s):  
Nitrogen Fixation ◽  
Rhizobium Leguminosarum ◽  
Root Nodules ◽  
Lateral Roots ◽  
Transfer Cells ◽  
Xylem Parenchyma ◽  
Cortical Cells ◽  
Nitrogenous Compounds ◽  
Wall Ingrowths ◽  
Xylem Elements

Xylem parenchyma transfer cells are present in the stele of the root tissue adjacent to emergent effective root nodules of garden pea (Pisum sativum), red kidney bean (Phaseolus vulgaris), broad bean (Vicia faba), soybean (Glycine max), and mung bean (Vigna radiata), two types of ineffective pea nodules, and emergent lateral roots of pea. The xylem parenchyma transfer cells contain many polyribosomes and mitochondria near the wall ingrowths which are located adjacent to pits in the xylem elements. Pericycle transfer cells also occur in the three types of pea nodules. In effective pea nodules wall ingrowths begin to form in the pericycle cells 5 days after inoculation with Rhizobium leguminosarum; at this stage rhizobia are only present in the root hair but the cortical cells have enlarged and some have undergone mitosis. The wall ingrowths begin to form in the xylem parenchyma cells 7–8 days after inoculation or the approximate time that rhizobia begin to be released from the infection thread. In both instances the wall ingrowths begin to form before the onset of dinitrogen reduction although previous workers have suggested that a flux of nitrogenous compounds (containing fixed N) induces their formation. The development of wall ingrowths in ineffective pea nodules also occurs independently of nitrogen fixation. Similarly, the wall ingrowths located near soybean nodules also begin to develop before the onset of nitrogen fixation.

scholarly journals Identification of Cytokinins of Root Nodules of the Garden Pea, Pisum sativum L.

1976 ◽  
Vol 57 (4) ◽  
pp. 602-606 ◽  
Author(s):  
Kunihiko Syõno ◽  
John G. Torrey
Keyword(s):  
Pisum Sativum ◽  
Root Nodules ◽  
Garden Pea ◽  
Pisum Sativum L

Pisum sativum cultivar effects on hydrogen metabolism in Rhizobium

1984 ◽  
Vol 62 (8) ◽  
pp. 1682-1686 ◽  
Author(s):  
Eulogio J. Bedmar ◽  
Donald A. Phillips
Keyword(s):  
Pisum Sativum ◽  
Relative Efficiency ◽  
Rhizobium Leguminosarum ◽  
Root Nodules ◽  
Developmental Differences ◽  
The Other ◽  
Hydrogenase Activity ◽  
Uptake Hydrogenase ◽  
Hydrogen Metabolism ◽  
Pisum Sativum L

Data from 14 Pisum sativum L. cultivars establish that three pea genotypes, which were previously reported to affect net H2 evolution from root nodules in air and uptake hydrogenase activity of Rhizobium leguminosarum 128C53, are not unique. Two pea lines, 'JI1205' and 'Green Arrow,' produced very active uptake hydrogenase activity in strain 128C53, and essentially no H2 was evolved in air from root nodules capable of reducing 20 μmol C2H2 ∙ plan−1 ∙ h−1. Five other cultivars produced significantly lower uptake hydrogenase activities in the same bacterial strain and had much higher rates of net H2 evolution with similar C2H2-reduction capabilities. Parallel experiments with the same cultivars nodulated by R. leguminosarum 300, an organism with no convincing uptake hydrogenase activity in any pea line, showed that 'JI1205' and 'Green Arrow' had a significantly lower relative efficiency (RE) of N2 fixation (1 − (H2 evolved in air/C2H2 reduced)) than the other five cultivars. Developmental differences among the pea lines prevented any conclusion about the advantages or disadvantages of uptake hydrogenase activity for plant growth, but in general, cultivars with high uptake hydrogenase activity and low net H2 evolution grew more slowly than those evolving large amounts of H2.

scholarly journals Proliferation of peroxisomes in pea root nodules - an influence of NaCI- or Hg2+- stress conditions

2011 ◽  
Vol 76 (4) ◽  
pp. 287-298 ◽  
Author(s):  
Wojciech Borucki
Keyword(s):  
Oxidative Stress ◽  
Electron Microscopy ◽  
Nitrogen Fixation ◽  
Pisum Sativum ◽  
Root Nodules ◽  
Light And Electron Microscopy ◽  
Nitrogen Fixing ◽  
Morphometric Measurements ◽  
Meristematic Cells ◽  
Pea Root

Morphometric procedures were used to examine peroxisome number and di-stribution in pea (<em>Pisum sativum</em> L.) root nodules under NaCl (50 mM) or HgCl<sub>2</sub> (7.3 µM) treatment. Peroxisomes were visualized cytochemically in meristem, invasion zone and prefixing zone of pea root nodules by catalase (EC 1.11.1.6) activity. The observations using light and electron microscopy revealed that the peroxisomes were predominantly spherical in shape and showed catalase activity. In nitrogen fixation zone, catalase active peroxisomes were observed occasionally. Bacteroids of nitrogen fixing zone showed enhanced cata-lase activity probably as a response to higher level of oxidative stress. Fluorescence microscopy investigations revealed enhanced level of (homo)glutathione in prefixing and nitrogen-fixing zone of NaCl- and Hg<sup>2+</sup>treated nodules, which served as an indicator of antioxidative response. Morphometric measurements revealed that during differentiation of meristematic cells into central tissue (bacteroidal tissue) cells an increase in peroxisome number was observed in unstressed nodules. Peroxisomes located in meristem, invasion zone and prefixing zone of NaCl- and Hg<sup>2+</sup>-treated nodules outnumbered that in control nodules. A substantial enlargement of peroxisome profiles was detected in NaCl- and Hg<sup>2+</sup>treated nodules. Peroxisome divisions observed in meristematic and infection thread penetration zone were responsible for an increase in peroxisome number.

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