scholarly journals Morphogenesis of root nodules in white clover. III. The effect of mutation in nod IJ genes of the microsymbiont upon the DNA level in the host tissue

2014 ◽  
Vol 67 (1) ◽  
pp. 23-29
Author(s):  
Barbara Łotocka ◽  
Władysław Golinowski
Keyword(s):  
White Clover ◽  
Rhizobium Leguminosarum ◽  
Root Nodule ◽  
Nuclear Dna ◽  
Root Nodules ◽  
Root Hairs ◽  
Infection Threads ◽  
Dna Contents ◽  
Mutant Strains ◽  
Nuclear Dna Contents

On the basis of cytophotometric measurements a slightly increased DNA level in the nuclei of curled root hairs containing infection threads was observed in white clover inoculated with wild and mutant strains of <em>Rhizobium leguminosarum</em> biovar. <em>trifolii</em>, as compared to normal root hairs of te same plants. Cells of the root nodule primordia in 72 h after the inoculation, as compared to the root primary cortex, demonstrated an increased level of the nuclear DNA. No differences were observed in the nuclear DNA contents in individual layers of the cortex of the 28 day-old nodules. Generally it was low, varying from 2c to 4c. The meristematic and bacteroidal tissues in the effective nodules were characterized by a higher DNA level, as compared to the respective zones in ineffective nodules induced with the strains ANU261 (<em>nod I<sup>*</sup></em>) and ANU262 (<em>nod J<sup>*</sup></em>). The DNA level in the effective bacteroidal tissue varied from 4c to 32c, while in the tissue containing the strain ANU26l only the 2c-8c nuclei could be found and in the tissue with the strain ANU262 - the 4c-16c nuclei.

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.

scholarly journals Development of Functional Symbiotic White Clover Root Hairs and Nodules Requires Tightly Regulated Production of Rhizobial Cellulase CelC2

2011 ◽  
Vol 24 (7) ◽  
pp. 798-807 ◽  
Author(s):  
Marta Robledo ◽  
José I. Jiménez-Zurdo ◽  
M. José Soto ◽  
Encarnación Velázquez ◽  
Frank Dazzo ◽  
...  
Keyword(s):  
Cell Wall ◽  
White Clover ◽  
Rhizobium Leguminosarum ◽  
Plant Cell Wall ◽  
Root Nodules ◽  
Root Hairs ◽  
Nitrogen Fixing ◽  
Plant Host ◽  
Root Cortex ◽  
Infection Threads

The establishment of rhizobia as nitrogen-fixing endosymbionts within legume root nodules requires the disruption of the plant cell wall to breach the host barrier at strategic infection sites in the root hair tip and at points of bacterial release from infection threads (IT) within the root cortex. We previously found that Rhizobium leguminosarum bv. trifolii uses its chromosomally encoded CelC2 cellulase to erode the noncrystalline wall at the apex of root hairs, thereby creating the primary portal of its entry into white clover roots. Here, we show that a recombinant derivative of R. leguminosarum bv. trifolii ANU843 that constitutively overproduces the CelC2 enzyme has increased competitiveness in occupying aberrant nodule-like root structures on clover that are inefficient in nitrogen fixation. This aberrant symbiotic phenotype involves an extensive uncontrolled degradation of the host cell walls restricted to the expected infection sites at tips of deformed root hairs and significantly enlarged infection droplets at termini of wider IT within the nodule infection zone. Furthermore, signs of elevated plant host defense as indicated by reactive oxygen species production in root tissues were more evident during infection by the recombinant strain than its wild-type parent. Our data further support the role of the rhizobial CelC2 cell wall–degrading enzyme in primary infection, and show evidence of its importance in secondary symbiotic infection and tight regulation of its production to establish an effective nitrogen-fixing root nodule symbiosis.

scholarly journals Nuclear DNA contents, rDNAs, and karyotype evolution in subgenus Vicia: III. The heterogeneous section Hypechusa

PROTOPLASMA ◽  
2006 ◽  
Vol 228 (4) ◽  
pp. 167-177 ◽  
Author(s):  
P. Caputo ◽  
M. Frediani ◽  
G. Venora ◽  
C. Ravalli ◽  
M. Ambrosio ◽  
...  
Keyword(s):  
Nuclear Dna ◽  
Karyotype Evolution ◽  
Dna Contents ◽  
Nuclear Dna Contents

scholarly journals Heterologous Expression of Rhizobial CelC2 Cellulase Impairs Symbiotic Signaling and Nodulation in Medicago truncatula

2018 ◽  
Vol 31 (5) ◽  
pp. 568-575 ◽  
Author(s):  
Marta Robledo ◽  
Esther Menéndez ◽  
Jose Ignacio Jiménez-Zurdo ◽  
Raúl Rivas ◽  
Encarna Velázquez ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Cell Walls ◽  
Rhizobium Leguminosarum ◽  
Root Nodules ◽  
Root Hairs ◽  
Nod Factors ◽  
Model Legume ◽  
Ensifer Meliloti ◽  
Early Nodulin ◽  
The Impact

The infection of legume plants by rhizobia is tightly regulated to ensure accurate bacterial penetration, infection, and development of functionally efficient nitrogen-fixing root nodules. Rhizobial Nod factors (NF) have key roles in the elicitation of nodulation signaling. Infection of white clover roots also involves the tightly regulated specific breakdown of the noncrystalline apex of cell walls in growing root hairs, which is mediated by Rhizobium leguminosarum bv. trifolii cellulase CelC2. Here, we have analyzed the impact of this endoglucanase on symbiotic signaling in the model legume Medicago truncatula. Ensifer meliloti constitutively expressing celC gene exhibited delayed nodulation and elicited aberrant ineffective nodules, hampering plant growth in the absence of nitrogen. Cotreatment of roots with NF and CelC2 altered Ca2+ spiking in root hairs and induction of the early nodulin gene ENOD11. Our data suggest that CelC2 alters early signaling between partners in the rhizobia-legume interaction.

Nuclear DNA Contents of Coreopsis nuecensoides and C. nuecensis (Asteraceae), a Progenitor-Derivative Species Pair

1984 ◽  
Vol 145 (2) ◽  
pp. 240-245 ◽  
Author(s):  
H. James Price ◽  
Daniel J. Crawford ◽  
Randall J. Bayer
Keyword(s):  
Nuclear Dna ◽  
Species Pair ◽  
Dna Contents ◽  
Nuclear Dna Contents

Flow cytometric analysis reveals different nuclear DNA contents in cultivated Fonio (Digitaria spp.) and some wild relatives from West-Africa

2007 ◽  
Vol 267 (1-4) ◽  
pp. 163-176 ◽  
Author(s):  
H. Adoukonou-Sagbadja ◽  
V. Schubert ◽  
A. Dansi ◽  
G. Jovtchev ◽  
A. Meister ◽  
...  
Keyword(s):  
West Africa ◽  
Nuclear Dna ◽  
Flow Cytometric Analysis ◽  
Wild Relatives ◽  
Flow Cytometric ◽  
Dna Contents ◽  
Nuclear Dna Contents

Nuclear DNA content of three Eucalyptus species estimated by flow and image cytometry

2009 ◽  
Vol 57 (6) ◽  
pp. 524 ◽  
Author(s):  
Milene Miranda Praça ◽  
Carlos Roberto Carvalho ◽  
Carolina Ribeiro Diniz Boaventura Novaes
Keyword(s):  
Dna Content ◽  
Nuclear Dna ◽  
Methodological Approach ◽  
Nuclear Dna Content ◽  
Image Cytometry ◽  
Eucalyptus Species ◽  
International Consensus ◽  
Mean Values ◽  
Dna Contents ◽  
Nuclear Dna Contents

Previous flow cytometry (FCM) analyses delivered nearly equal mean values of nuclear 2C DNA content for Eucalyptus grandis Hill ex Maiden and E. urophylla S. T. Blake (1.33 pg and 1.34 pg, respectively), whereas E. globulus Labill. presented distinct mean values (1.09, 1.13 and 1.40). These differences have been attributed to the different methodological approach, utilised plant cultivar and presence of intrinsic metabolic compounds that affect fluorochrome fluorescence. In the present study, a FCM and image cytometry (ICM) design, following international consensus criteria, were adopted to reassess the nuclear DNA contents of the above-mentioned Eucalyptus species. Statistical analyses revealed either similar or discrepant nuclear DNA contents, depending on the standard species used and whether FCM or ICM was employed. Our results demonstrated that 2C DNA values obtained by FCM and ICM were most uniform when Solanum lycopersicum was used as a standard. Moreover, the values obtained for E. grandis and E. urophylla were close, but differed as much as 24.63% in relation to previous data, and E. globulus proportionally varied up to 25%. New DNA content values are suggested for these eucalypt species.

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