scholarly journals Specific Flavonoids Promote Intercellular Root Colonization of Arabidopsis thaliana by Azorhizobium caulinodans ORS571

1997 ◽  
Vol 10 (5) ◽  
pp. 560-570 ◽  
Author(s):  
Clare Gough ◽  
Christine Galera ◽  
Jacques Vasse ◽  
Gordon Webster ◽  
Edward C. Cocking ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Colonization ◽  
Lateral Roots ◽  
Nod Factors ◽  
Azorhizobium Caulinodans ◽  
Nutritional Factors ◽  
High Frequencies ◽  
Cell Layers ◽  
Azorhizobium Caulinodans Ors571 ◽  
Stimulation Of

The ability of Azorhizobium caulinodans ORS571 and other diazotrophic bacteria to internally colonize roots of Arabidopsis thaliana has been studied. Strains tagged with lacZ or gusA reporter genes were used, and the principal colonization sites were found to be the points of emergence of lateral roots, lateral root cracks (LRCs). High frequencies of colonization were found; 63 to 100% of plants were colonized by ORS571, and 100% of plants were colonized by Herbaspirillum seropedicae. After LRCs were colonized, bacteria moved into intercellular spaces between the cortical and endodermal cell layers. Specific flavonoids, naringenin and daidzein, at 5 × 10-5 M, significantly promoted colonization by ORS571. By using a nodC and a nodD mutant of ORS571, it was shown that neither Nod factors nor NodD are involved in colonization or flavonoid stimulation of colonization. Flavonoids did not appear to be stimulating LRC colonization by their activity as nutritional factors. LRC and intercellular colonization by H. seropedicae was stimulated by naringenin and daidzein at the same concentration that stimulated colonization by ORS571.

scholarly journals Azorhizobium caulinodans ORS571 Colonizes the Xylem of Arabidopsis thaliana

2001 ◽  
Vol 14 (1) ◽  
pp. 93-97 ◽  
Author(s):  
Philip J. Stone ◽  
Kenneth J. O'Callaghan ◽  
Michael R. Davey ◽  
Edward C. Cocking
Keyword(s):  
Arabidopsis Thaliana ◽  
Lateral Roots ◽  
Microscopic Analysis ◽  
Azorhizobium Caulinodans ◽  
Nodulation Factors ◽  
Significant Difference ◽  
The Mean ◽  
Primary And Lateral Roots ◽  
Azorhizobium Caulinodans Ors571 ◽  
Intact Roots

Improved conditions were used for the aseptic growth of Arabidopsis thaliana to investigate whether xylem colonization of A. thaliana by Azorhizobium caulinodans ORS571 might occur. When seedlings were inoculated with ORS571 (pXLGD4) tagged with the lacZ reporter gene, nearly all of the plants showed blue regions of ORS571 colonization at lateral root cracks (LRC). The flavonoids naringenin and liquiritigenin significantly stimulated colonization of LRC by ORS571. Blue bands of ORS571 (pXLGD4) bacteria were observed histochemically in the xylem of intact roots of inoculated plants. Detailed microscopic analysis of sections of primary and lateral roots from inoculated A. thaliana confirmed xylem colonization. Xylem colonization also occurred with an ORS571 nodC mutant deficient in nodulation factors. There was no significant difference in the percentage of plants with xylem colonization or in the mean length of xylem colonized per plant between plants inoculated with either ORS571 (pXLGD4) or ORS571::nodC (pXLGD4), with or without naringenin.

scholarly journals COLONIZATION of Rubus glaucus BENTH BY AZORHIZOBIUM CAULINODANS ORS571 USIG A FLAVONOIDE NARINGENINA

2016 ◽  
Vol 14 (2) ◽  
pp. 15
Author(s):  
Giovani Orlando Cancino Escalante ◽  
S E Cancino ◽  
Enrique Quevedo Garcia
Keyword(s):  
Bacterial Colonization ◽  
Lateral Roots ◽  
Plant Growth Promoting Bacteria ◽  
Azorhizobium Caulinodans ◽  
Intensity Parameters ◽  
Plant Growth Promoting ◽  
Measuring Frequency ◽  
Northwest Region ◽  
Azorhizobium Caulinodans Ors571

Root systems of two Andean blackberry materials (thorn and thornless) of Rubus glaucus Benth cultured in vitro in the presence of five treatments (four flavonoids and one control) were inoculated with Azorhizobium caulinodans ORS571 (pXLGD4)  (a strain carrying the lacZ reporter gene which facilitated the detection of bacterial colonization). Evaluation of colonization effectiveness for each treatment was done by means of application of experimental design measuring frequency and intensity parameters. Statistical analysis showed differences at comparing flavonoids vs. control and the overall higher effectiveness of the flavonoid naringenin. Observation of colonization was made by light and electron microscope confirming internal colonization of Andean blackberry roots by A. caulinodans. This is the first work demonstrating root colonization of R.glaucus by azorhizobia and therefore settling the basis for future investigations and scientific applications related to interaction with plant growth-promoting bacteria under the effect of flavonoids, along with possible implications of common benefit for non-legume crops in the northwest region of Colombia.  Key Words: Azorhizobium caulinodans ORS571, Andean blackberry, flavonoids, LacZ, lateral roots, naringenin. 

Root nodulation of Sesbania rostrata suppresses stem nodulation by Sinorhizobium teranga but not Azorhizobium caulinodans

1996 ◽  
Vol 42 (2) ◽  
pp. 187-190 ◽  
Author(s):  
Kodjo Tomekpe ◽  
Marcelle Holsters ◽  
Bernard Dreyfus
Keyword(s):  
Host Plant ◽  
Root Nodules ◽  
Sesbania Rostrata ◽  
Efficient Production ◽  
Nod Factors ◽  
Azorhizobium Caulinodans ◽  
Experimental Conditions ◽  
Nod Factor ◽  
Stem Nodulation ◽  
Azorhizobium Caulinodans Ors571

Azorhizobium caulinodans ORS571 and Sinorhizobium teranga ORS51 and ORS52 are symbionts of the same host plant Sesbania rostrata. In nature, A. caulinodans nodulates more competitively the stem-located infection sites of Sesbania rostrata. Sinorhizobium strains, although frequently present in root nodules, are seldom found in stem nodules. One probable explanation for this phenomenon is the more abundant presence of Azorhizobium on the leaf and stem surfaces of the host plant. Work presented here hints at other plausible factors that determine the greater "stem specificity" of Azorhizobium. We found that under experimental conditions in which roots are not inoculated, all strains nodulated stems very well. However, ORS51 and ORS52 were much more sensitive than ORS571 to suppression of stem nodulation by previous root inoculation. The introduction of the regulatory nodD gene from A. caulinodans diminished the sensitivity to this suppression, probably by enhanced nod gene expression and subsequent Nod factor production. Our hypothesis is that the greater infectivity of ORS571 is due to a more efficient production of mitogenic Nod factors at stem-located infection sites, thereby more readily overcoming systemic suppression caused by previous root inoculations.Key words: autoregulation, nitrogen fixation, rhizobial ecology, systemic suppression of nodulation.

scholarly journals Carbamoylation of Azorhizobial Nod Factors Is Mediated by NodU

1999 ◽  
Vol 12 (1) ◽  
pp. 68-73 ◽  
Author(s):  
Wim D'Haeze ◽  
Marc Van Montagu ◽  
Jean-Claude Promé ◽  
Marcelle Holsters
Keyword(s):  
Escherichia Coli ◽  
Structural Analysis ◽  
Nod Factors ◽  
Azorhizobium Caulinodans ◽  
Terminal Residue ◽  
Azorhizobium Caulinodans Ors571 ◽  
Sequence Similarities ◽  
Carbamoyl Group

Lipochitooligosaccharides (LCOs) synthesized by Azorhizobium caulinodans ORS571 are substituted at the nonreducing-terminal residue with a 6-O-carbamoyl group. LCO biosynthesis in A. caulinodans is dependent on the nodABCSUIJZnoeC operon. Until now, the role of the nodulation protein NodU in the synthesis of azorhizobial LCOs remained unclear. Based on sequence similarities and structural analysis of LCOs produced by a nodU mutant, a complemented nodU mutant, and Escherichia coli DH5α expressing the nodABCSU genes, NodU was shown to be involved in the carbamoylation step.

Utilization of a hydrate cellulose film for investigation of Arabidopsis thaliana L. root system growth and development

2020 ◽  
Vol 36 (1) ◽  
pp. 36-43
Author(s):  
I.O. Konovalova ◽  
T.N. Kudelina ◽  
S.O. Smolyanina ◽  
A.I. Lilienberg ◽  
T.N. Bibikova
Keyword(s):  
Arabidopsis Thaliana ◽  
Root System ◽  
Life Support ◽  
Higher Plants ◽  
Plant Root ◽  
Lateral Roots ◽  
Basic Research ◽  
Cellulose Film ◽  
A New Technique ◽  
Basic Research Project

A new technique for Arabidopsis thaliana cultivation has been proposed that combines the use of a phytogel-based nutrient medium and a hydrophilic membrane of hydrate cellulose film, separating the root system of the plant from the medium thickness. Growth rates of both main and lateral roots were faster in the plants cultivated on the surface of hydrate cellulose film than in the plants grown in the phytogel volume. The location of the root system on the surface of the transparent hydrate film simplifies its observation and analysis and facilitates plant transplantation with preservation of the root system configuration. The proposed technique allowed us to first assess the effect of exogenous auxin on the growth of lateral roots at the 5-6 developmental stage. methods to study plant root systems, hydrate cellulose film, A. thaliana, lateral roots, differential root growth rate, auxin The work was financially supported by the Russian Foundation for Basic Research (Project Bel_mol_a 19-54-04015) and the basic topic of the Russian Academy of Sciences - IBMP RAS «Regularities of the Influence of Extreme Environmental Factors on the Processes of Cultivation of Higher Plants and the Development of Japanese Quail Tissues at Different Stages of its Ontogenesis under the Conditions of Regenerative Life Support Systems».

Formation of lateral root meristems is a two-stage process

Development ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3303-3310 ◽  
Author(s):  
M.J. Laskowski ◽  
M.E. Williams ◽  
H.C. Nusbaum ◽  
I.M. Sussex
Keyword(s):  
Lateral Root ◽  
Lateral Roots ◽  
Initial Period ◽  
Subsequent Stage ◽  
Root Initiation ◽  
Root Meristems ◽  
Lateral Root Initiation ◽  
Cell Layers ◽  
Stage Process ◽  
Pericycle Cells

In both radish and Arabidopsis, lateral root initiation involves a series of rapid divisions in pericycle cells located on the xylem radius of the root. In Arabidopsis, the number of pericycle cells that divide to form a primordium was estimated to be about 11. To determine the stage at which primordia are able to function as root meristems, primordia of different stages were excised and cultured without added hormones. Under these conditions, primordia that consist of 2 cell layers fail to develop while primordia that consist of at least 3–5 cell layers develop as lateral roots. We hypothesize that meristem formation is a two-step process involving an initial period during which a population of rapidly dividing, approximately isodiametric cells that constitutes the primordium is formed, and a subsequent stage during which meristem organization takes place within the primordium.

Sign in / Sign up

Export Citation Format

Share Document