scholarly journals Mechanism of Infection Thread Elongation in Root Hairs of Medicago truncatula and Dynamic Interplay with Associated Rhizobial Colonization

2008 ◽  
Vol 148 (4) ◽  
pp. 1985-1995 ◽  
Author(s):  
Joëlle Fournier ◽  
Antonius C.J. Timmers ◽  
Björn J. Sieberer ◽  
Alain Jauneau ◽  
Mireille Chabaud ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Root Hairs ◽  
Infection Thread ◽  
Dynamic Interplay

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.

scholarly journals A repertoire of cationic and anionic conductances at the plasma membrane of Medicago truncatula root hairs

2019 ◽  
Vol 98 (3) ◽  
pp. 418-433 ◽  
Author(s):  
Limin Wang ◽  
Man‐Yuan Guo ◽  
Jean‐Baptiste Thibaud ◽  
Anne‐Aliénor Véry ◽  
Hervé Sentenac
Keyword(s):  
Plasma Membrane ◽  
Medicago Truncatula ◽  
Root Hairs

scholarly journals The Small GTPase ROP10 of Medicago truncatula Is Required for Both Tip Growth of Root Hairs and Nod Factor-Induced Root Hair Deformation

2015 ◽  
Vol 27 (3) ◽  
pp. 806-822 ◽  
Author(s):  
Ming-Juan Lei ◽  
Qi Wang ◽  
Xiaolin Li ◽  
Aimin Chen ◽  
Li Luo ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Root Hair ◽  
Tip Growth ◽  
Root Hairs ◽  
Small Gtpase ◽  
Nod Factor ◽  
Root Hair Deformation

Infection thread formation as a basis of nodulation specificity in Rhizobium – strawberry clover associations

1969 ◽  
Vol 15 (10) ◽  
pp. 1133-1136 ◽  
Author(s):  
Diana Li ◽  
D. H. Hubbell
Keyword(s):  
Characteristic Root ◽  
Root Hairs ◽  
Infection Thread ◽  
Root Hair Deformation ◽  
Infection Threads ◽  
Specific Substance ◽  
Thread Formation ◽  
Nodulation Specificity ◽  
Infection Thread Formation

The basis for determination of nodulating specificity in Rhizobium–clover associations was investigated. Thirteen strains of rhizobia from eight different cross-inoculation groups were used to inoculate aseptically grown strawberry clover seedlings in slide culture. Microscopic observation revealed that each strain produced characteristic root hair deformation but infection threads and nodules were observed only in the homologous combination. It is concluded that, in rhizobia–clover combinations which nodulate via infection threads, specificity is determined at or before infection thread initiation. Observations of other workers that rhizobia produce a strain-specific substance affecting growth and morphology of legume root hairs were confirmed by results of this study.

scholarly journals Conservation in Function of a SCAR/WAVE Component During Infection Thread and Root Hair Growth in Medicago truncatula

2010 ◽  
Vol 23 (12) ◽  
pp. 1553-1562 ◽  
Author(s):  
Akira Miyahara ◽  
Jennifer Richens ◽  
Colby Starker ◽  
Giulia Morieri ◽  
Lucinda Smith ◽  
...  
Keyword(s):  
Medicago Truncatula ◽  
Root Hair ◽  
Actin Polymerization ◽  
Infection Thread ◽  
Plant Host ◽  
Homologous Protein ◽  
Infection Threads ◽  
Cellular Junctions ◽  
Root Hair Growth ◽  
Camp Receptor

Nitrogen-fixing symbioses of plants are often associated with bacterially infected nodules where nitrogen fixation occurs. The plant host facilitates bacterial infection with the formation of infection threads, unique structures associated with these symbioses, which are invaginations of the host cell with the capability of traversing cellular junctions. Here, we show that the infection thread shares mechanistic similarities to polar-growing cells, because the required for infection thread (RIT) locus of Medicago truncatula has roles in root-hair, trichome, and infection-thread growth. We show that RIT encodes the M. truncatula ortholog of NAP1, a component of the SCAR/WAVE (suppressor of cAMP receptor/WASP-family verprolin homologous protein) complex that regulates actin polymerization, through the activation of ARP2/3. NAP1 of Arabidopsis thaliana functions equivalently to the M. truncatula gene, indicating that the mode of action of NAP1 is functionally conserved across species and that legumes have not evolved a unique functionality for NAP1 during rhizobial colonization. This work highlights the surprising commonality between polar-growing cells and a polar-growing cellular intrusion and reveals important insights into the formation and maintenance of infection-thread development.

Early events in the infection of soybean by Rhizobium japonicum. Time course and cytology of the initial infection process

1982 ◽  
Vol 60 (2) ◽  
pp. 152-161 ◽  
Author(s):  
B. Gillian Turgeon ◽  
Wolfgang D. Bauer
Keyword(s):  
Root Hair ◽  
Time Course ◽  
Cortical Cell ◽  
Root Hairs ◽  
Infection Process ◽  
Infection Thread ◽  
Rhizobium Japonicum ◽  
Outer Cortex ◽  
Light Microscope Level ◽  
Infection Threads

The time course of early infection events in Glycine max following inoculation with Rhizobium japonicum is described. Bacteria became attached to epidermal cells and root hairs within minutes of inoculation. Marked root hair curling occurred within 12 h. Infection thread formation was visible at the light microscope level of resolution about 24 h after inoculation. Infections were observed in short, tightly curled root hairs. These root hairs had not yet emerged at the time of inoculation. Infection threads appeared to originate in pockets formed by contact of the cell wall of the curled root hair with itself. Infection threads in the hairs were multiple and (or) branched. By 48 h, the infection thread(s) had progressed to the base of the root hair but had not yet penetrated into the cortex. Increases in cortical cell cytoplasm and in mitotic division occurred in advance of the penetrating infection thread. A nodule meristem developed in the outer cortex next to the infected root hair by 4 days and was accompanied by cell division across the cortex.

scholarly journals Soil protists can actively redistribute beneficial bacteria along Medicago truncatula roots

2021 ◽  
Author(s):  
Christopher J. Hawxhurst ◽  
Jamie L Micciulla ◽  
Charles M Bridges ◽  
Leslie M Shor ◽  
Daniel J. Gage
Keyword(s):  
Medicago Truncatula ◽  
Sinorhizobium Meliloti ◽  
Root Hairs ◽  
Plant Health ◽  
Nitrogen Fertilizers ◽  
Bacterial Transport ◽  
Root Tip ◽  
Soil Microcosms ◽  
Beneficial Bacterium ◽  
Soil Protists

The rhizosphere is the region of soil directly influenced by plant roots. The microbial community in the rhizosphere includes fungi, protists, and bacteria, all of which play a significant role in plant health. The beneficial bacterium Sinorhizobium meliloti infects growing root hairs on nitrogen starved leguminous plants. Infection leads to the formation of a root nodule, where S. meliloti converts atmospheric nitrogen to ammonia, the usable form of nitrogen for plants. However, S. meliloti, often found in biofilms, travels slowly; whereas infectible root hairs are found at the growing root tip, potentially causing many root hairs to remain uninfected by S. meliloti when it is delivered as a seed inoculant. Soil protists are an important component of the rhizosphere system who prey on soil bacteria and have been known to egest undigested phagosomes. We show that the soil protist, Colpoda sp., plays an important role in transporting S. meliloti down Medicago truncatula roots. By using pseudo-3D soil microcosms we directly observed the presence of fluorescently labelled S. meliloti along M. truncatula roots and track the displacement of bacteria over time. In the presence of Colpoda sp., S. meliloti was detected 44 mm, on average, farther down the roots, compared with the Bacteria Only Treatment. Facilitating bacterial transport may be an important mechanism whereby soil protists promote plant health. Protist facilitated transport as a sustainable agriculture biotechnology has the potential to boost efficacy of bacterial inoculants, avoid overuse of nitrogen fertilizers, and enhance performance of no-till farming practices.

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