Evidence countering the role of polygalacturonase in invasion of root hairs of leguminous plants by Rhizobium spp.

1968 ◽  
Vol 14 (6) ◽  
pp. 617-625 ◽  
Author(s):  
Thomas T. Lillich ◽  
Gerald H. Elkan
Keyword(s):  
Enzyme Activity ◽  
Glycine Max ◽  
Sole Carbon Source ◽  
Root Hairs ◽  
Rhizobium Japonicum ◽  
Leguminous Plants ◽  
Uninoculated Control ◽  
Rhizobium Spp ◽  
Polygalacturonase Activity

Polygalacturonase has been postulated as being involved in the invasion of the host legume by Rhizobium spp. The role of this enzyme in the invasion of Glycine max by Rhizobium japonicum was investigated. Enzyme activity of several Rhizobium spp. was assayed viscometrically and no constitutive polygalacturonase was found. The enzyme could not be induced by growth with either pectin or galactose as the sole carbon source. Extract and exudate from the roots of nodulating and nonnodulating strains of Glycine max that had been incubated with effective strains of R. japonicum failed to show any higher levels of polygalacturonase activity than did uninoculated control plants. Previously reported experiments were duplicated. Levels of polygalacturonase activity from the extract and exudate of white clover inoculated with R. trifolii Cl 226 were as reported in the literature. Contrary to published reports, however, no greater levels of enzyme activity were found from effective plant–bacteria associations than from either ineffective associations or uninoculated control plants. It was concluded from these experiments that polygalacturonase does not play a major role in the invasion of Glycine max by Rhizobium japonicum.

Plasmid replicons of Rhizobium

2005 ◽  
Vol 33 (1) ◽  
pp. 157-158 ◽  
Author(s):  
L.C. Crossman
Keyword(s):  
Short Review ◽  
Nitrogen Fixing ◽  
Rhizobium Etli ◽  
Free Living ◽  
Leguminous Plants ◽  
Symbiotic Plasmid ◽  
Rhizobium Spp ◽  
Plasmid Replicons ◽  
Rhizobium Sp

Rhizobium spp. are found in soil. They are both free-living and found symbiotically associated with the nodules of leguminous plants. Traditionally, studies have focused on the association of these organisms with plants in nitrogen-fixing nodules, since this is regarded as the most important role of these bacteria in the environment. Rhizobium sp. are known to possess several replicons. Some, like the Rhizobium etli symbiotic plasmid p42d and the plasmid pNGR234b of Rhizobium NGR234, have been sequenced and characterized. The plasmids from these organisms are the focus of this short review.

Calcium, Iron and Cobalt Accumulation in Root Hairs of Soybean (Glycine max)

1985 ◽  
Vol 40 (11-12) ◽  
pp. 912-913 ◽  
Author(s):  
Dietrich Werner ◽  
Klaus-Peter Kuhlmann ◽  
Frank Gloystein ◽  
Friedrich-W. Richter
Keyword(s):  
Triticum Aestivum ◽  
Glycine Max ◽  
Root System ◽  
Root Hairs ◽  
The Other ◽  
Rhizobium Japonicum ◽  
Target Cells ◽  
Iron Cobalt ◽  
Calcium Iron

Abstract Root hairs of soybeans (Glycine max), target cells for infection by Rhizobium japonicum accumulate iron more than 10-fold, cobalt more than 8-fold and calcium more than 7-fold compared to the other parts of the root system. In root hairs of wheat (Triticum aestivum) a much smaller accumulation of these elements was found. The symbiont of Glycine max, Rhizobium japonicum, is known to have a high requirement for iron, cobalt and calcium.

Evidence against involvement of pectic enzymes in the invasion of root hairs by Rhizobium trifolii

1969 ◽  
Vol 15 (6) ◽  
pp. 643-645 ◽  
Author(s):  
James D. Macmillan ◽  
Roderic C. Cooke
Keyword(s):  
Root Hairs ◽  
Red Clover ◽  
Infection Process ◽  
Pectin Lyase ◽  
Rhizobium Trifolii ◽  
Leguminous Plants ◽  
Pectic Enzymes ◽  
Lyase Activity ◽  
Rhizobium Spp ◽  
Polygalacturonate Lyase

It has been postulated that polygalacturonase is significant in the infection of root hairs of leguminous plants by Rhizobium spp. Recently this theory has been strongly questioned. Evidence for polygalacturonase was based on methods which would not distinguish between this enzyme and other pectic glycosidases. The possibility that pectin lyase or polygalacturonate lyase is involved in the invasion of red clover by Rhizobium trifolii was investigated. Weak pectin lyase activity was detected in uninoculated seedlings, but no increase in the activity was produced in inoculated seedlings. It was concluded that neither of the lyases has significance in the infection process.

Role of pectic and cellulolytic enzymes in the invasion of the soybean by Rhizobium japonicum

1975 ◽  
Vol 21 (8) ◽  
pp. 1254-1258 ◽  
Author(s):  
William J. Hunter ◽  
Gerald H. Elkan
Keyword(s):  
Enzyme Activity ◽  
Indoleacetic Acid ◽  
Methyl Cellulose ◽  
Rhizobium Japonicum ◽  
Cellulolytic Enzymes ◽  
Pectic Acid ◽  
Pectic Enzyme ◽  
Seedling Inoculation

Past workers have suggested pectic enzyme involvement in the invasion of legumes by Rhizobium. However, no role for pectic acid, pectin, or methyl cellulose depolymerase enzymes in the invasion of R. japonicum was suggested by the current study. Seedling inoculation with infective bacteria did not result in increased enzyme activity. Rhizobium japonicum cell-free culture extracts and 3-indoleacetic acid did not affect the activation, induction, or binding of these enzymes.

Ecological studies of root-nodule bacteria introduced into field environments. 4. Symbiotic properties of Rhizobium japonicum and competitive success in nodulation of two Glycine max cultivars by effective and ineffective strains

1976 ◽  
Vol 16 (81) ◽  
pp. 514 ◽  
Author(s):  
A Diatloff ◽  
J Brockwell
Keyword(s):  
Glycine Max ◽  
Root Nodule ◽  
Rhizobium Japonicum ◽  
Nodule Formation ◽  
Nodule Bacteria ◽  
Naturally Occurring ◽  
Competitive Success ◽  
Uninoculated Control ◽  
Strain Interaction ◽  
Symbiotic Properties

Rhizobium japonicum strain evaluation experiments with soybean (Glycine max) confirmed that strain CB1809 was ineffective in nitrogen fixation with the related cultivars Hardee and Geduld but was highly effective with cv. Hampton. There were no major symbiotic differences between the cultivars with other strains. Three strains including CB1809 were used, singly, in pairs, or all together, as inocula for Hardee and Hampton in competition studies in the field. The ratio of strains recovered from nodules was used as an index of competitive success. A few nodules contained more than one strain. There was a marked host x strain interaction in nodulating competitiveness related to symbiotic effectiveness, the order of competitive success being CB1809 > CC709 > CB1795 for Hampton and CC709 > CB1795 > CB1809 for Hardee. With Hardee, strain CB1809, although unsuccessful itself in forming nodules in the presence of the other inocula, appeared to suppress nodule formation by those strains. Nodulation by CB1795 in the presence of CB1809 was suppressed to such an extent that plant growth was retarded and not different from that of uninoculated control plants, although CB1795 alone nodulated Hardee abundantly and effectively. There was no evidence that naturally-occurring ineffective R. japonicum posed any competitive threat to the nodulating ability of effective inoculant strains.

scholarly journals 3,4-dehydro-L-proline Induces Programmed Cell Death in the Roots of Brachypodium distachyon

2021 ◽  
Vol 22 (14) ◽  
pp. 7548
Author(s):  
Artur Pinski ◽  
Alexander Betekhtin ◽  
Jolanta Kwasniewska ◽  
Lukasz Chajec ◽  
Elzbieta Wolny ◽  
...  
Keyword(s):  
Cell Death ◽  
Brachypodium Distachyon ◽  
Root Hairs ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Cell Wall Proteins ◽  
Root Epidermis ◽  
Root Hair Development ◽  
Transmission Electron ◽  
Hair Development

As cell wall proteins, the hydroxyproline-rich glycoproteins (HRGPs) take part in plant growth and various developmental processes. To fulfil their functions, HRGPs, extensins (EXTs) in particular, undergo the hydroxylation of proline by the prolyl-4-hydroxylases. The activity of these enzymes can be inhibited with 3,4-dehydro-L-proline (3,4-DHP), which enables its application to reveal the functions of the HRGPs. Thus, to study the involvement of HRGPs in the development of root hairs and roots, we treated seedlings of Brachypodium distachyon with 250 µM, 500 µM, and 750 µM of 3,4-DHP. The histological observations showed that the root epidermis cells and the cortex cells beneath them ruptured. The immunostaining experiments using the JIM20 antibody, which recognizes the EXT epitopes, demonstrated the higher abundance of this epitope in the control compared to the treated samples. The transmission electron microscopy analyses revealed morphological and ultrastructural features that are typical for the vacuolar-type of cell death. Using the TUNEL test (terminal deoxynucleotidyl transferase dUTP nick end labelling), we showed an increase in the number of nuclei with damaged DNA in the roots that had been treated with 3,4-DHP compared to the control. Finally, an analysis of two metacaspases’ gene activity revealed an increase in their expression in the treated roots. Altogether, our results show that inhibiting the prolyl-4-hydroxylases with 3,4-DHP results in a vacuolar-type of cell death in roots, thereby highlighting the important role of HRGPs in root hair development and root growth.

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