Early events of vesicular–arbuscular mycorrhiza formation on Ri T‐DNA transformed roots

Bécard, Guillaume; Fortin, J. A.

doi:10.1111/j.1469-8137.1988.tb03698.x

Cited by 735 publications

(496 citation statements)

References 20 publications

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“…After 35±45 days, fresh roots were harvested for immunolocalisation studies and the remaining tissue was frozen in liquid N 2 and stored at ±80°C for RNA and protein isolation. Glomus intraradices was cultured with carrot hairy roots in two-compartment Petri-plates (St-Arnaud et al, 1996) and spores were prepared from these plates according to Be Â card and Fortin (1988). Inoculation of plants with Glomus intraradices spores was carried out according to Harrison and Dixon (1993).…”

Section: Methodsmentioning

confidence: 99%

The spatial expression patterns of a phosphate transporter (MtPT1) from Medicago truncatula indicate a role in phosphate transport at the root/soil interface

Chiou¹,

Liu²,

Harrison³

2001

The Plant Journal

182

145

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SummaryThe movement of phosphate from the soil into plant root cells is the ®rst of many crucial transport events required to supply phosphorous (P) to cells throughout the plant. In addition to the ability to acquire phosphate from the soil, the majority of the vascular plants are able to form arbuscular mycorrhizal associations in which phosphate may be delivered to the cortex via a fungus. Previously, we cloned two phosphate transporter genes, MtPT1 and MtPT2 from Medicago truncatula roots. Complementation of a yeast phosphate transport mutant revealed that MtPT1 is a functional phosphate transporter and Northern analyses revealed that MtPT1 is expressed exclusively in roots (Liu et al., 1998, Mol. Plant-Microbe Interact. 11, 14±22). Utilising an antibody speci®c for MtPT1, we have analysed the accumulation and spatial expression patterns of the MtPT1 transporter. MtPT1 transcript and protein levels show close correlation and increase dramatically in the roots in response to phosphate starvation. MtPT1 protein levels decrease in roots during development of a symbiosis with arbuscular mycorrhizal (AM) fungi, indicating that this transporter is not involved in symbiotic phosphate transport. Membrane fractionation and analysis of a MtPT1/GFP fusion protein revealed that MtPT1 is located in the plasma membrane, while in situ hybridisation and immunolocalisation demonstrate the presence of MtPT1 transcripts and protein in the epidermal cells and root hairs of M. truncatula roots. MtPT1 shows expression patterns consistent with a role speci®cally in the acquisition of phosphate from the soil and is distinct from the other phosphate transporter of this class described to date.

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Section: Methodsmentioning

confidence: 99%

The spatial expression patterns of a phosphate transporter (MtPT1) from Medicago truncatula indicate a role in phosphate transport at the root/soil interface

Chiou¹,

Liu²,

Harrison³

2001

The Plant Journal

182

145

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“…Rhizophagus irregularis (DAOM 197198), recently reassigned from Glomus intraradices Schenck and Smith (Krüger et al 2012), was produced in monoaxenic cultures maintained on Agrobacterium rhizogenes-transformed chicory roots (Bécard and Fortin 1988) in twocompartment Petri plates, as described in Pérez-Tienda et al (2011). Plates were incubated in the dark at 24 °C until the fungal compartment, which contained a solid M medium without sucrose (M-C medium), was profusely colonized by the fungus (approximately 6 weeks).…”

Section: Biological Materialsmentioning

confidence: 99%

The expression of GintPT, the phosphate transporter of Rhizophagus irregularis, depends on the symbiotic status and phosphate availability

Fiorilli

Lanfranco

Bonfante

2013

Planta

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The development of mutualistic interactions with arbuscular mycorrhizal (AM) fungi is one of the most important adaptation of terrestrial plants to face mineral nutrition requirements. As an essential plant nutrient, phosphorus uptake is acknowledged as a major benefit of the AM symbiosis, but the molecular mechanisms of its transport as inorganic phosphate (Pi) from the soil to root cells via AM fungi remain poorly known. Here we monitored the expression profile of the high-affinity phosphate transporter (PT) gene (GintPT) of Rhizophagus irregularis (DAOM 197198) in fungal structures (spores, extraradical mycelium and arbuscules), under different Pi availability, and in respect to plant connection. GintPT resulted constitutively expressed along the major steps of the fungal life cycle and the connection with the host plant was crucial to warrant GintPT high expression levels in the extraradical mycelium. The influence of Pi availability on gene expression of the fungal GintPT and the Medicago truncatula symbiosis-specific Pi transporter (MtPT4) was examined by qRT-PCR assay on microdissected arbusculated cells. The expression profiles of both genes revealed that these transporters are sensitive to changing Pi conditions: we observed that MtPT4 mRNA abundance is higher at 320 than at 32 μM suggesting that the flow towards the plant requires high concentrations. Taken on the whole, the findings highlight novel traits for the functioning of the GintPT gene and offer a molecular scenario to the models describing nutrient transfers as a cooperation between the mycorrhizal partners.

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“…Germination was induced under sterile conditions in 0.6% agar/water. Seedlings were transferred to minimal medium (Bécard and Fortin 1988) without sucrose and grown for 10 days in a growth chamber (16 h daylight at 21°C/8 h night at 18°C). Agrobacterium rhizogenes transformed roots from M. truncatula wild-type and the three mutants, dmi1-1 ), dmi2-2 (Endre et al 2002), dmi3-1 Mitra et al 2004) of M. truncatula Gaertn.…”

Section: Plant Materialsmentioning

confidence: 99%

“…cv. Jemalong (kindly provided by M. Chabaud and D. Barker, LIPM, Toulouse, France) were grown in sterile conditions in minimal medium at 25°C in the dark (Bécard and Fortin 1988). Arabidopsis thaliana seeds were sterilized with 1 min wash in 70% ethanol followed by 20 min wash in 10% commercial bleach and rinsed three times for 10 min with sterile distilled water.…”

Section: Plant Materialsmentioning

confidence: 99%

The exudate from an arbuscular mycorrhizal fungus induces nitric oxide accumulation in Medicago truncatula roots

et al. 2011

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Nitric oxide (NO) is a signaling molecule involved in plant responses to abiotic and biotic stresses. While there is evidence for NO accumulation during legume nodulation, almost no information exists for arbuscular mycorrhizas (AM). Here, we investigated the occurrence of NO in the early stages of Medicago truncatulaGigaspora margarita interaction, focusing on the plant response to fungal diffusible molecules. NO was visualized in root organ cultures and seedlings by confocal microscopy using the specific probe 4,5-diaminofluorescein diacetate. Five-minute treatment with the fungal exudate was sufficient to induce significant NO accumulation. The specificity of this response to AM fungi was confirmed by the lack of response in the AM nonhost Arabidopsis thaliana and by analyzing mutants impaired in mycorrhizal capacities. NO buildup resulted to be partially dependent on DMI1, DMI2, and DMI3 functions within the so-called common symbiotic signaling pathway which is shared between AM and nodulation. Significantly, NO accumulation was not induced by the application of purified Nod factor, while lipopolysaccharides from Escherichia coli, known to elicit defense-related NO production in plants, induced a significantly different response pattern. A slight upregulation of a nitrate reductase (NR) gene and the reduction of NO accumulation when the enzyme is inhibited by tungstate suggest NR as a possible source of NO. Genetic and cellular evidence, therefore, suggests that NO accumulation is a novel component in the signaling pathway that leads to AM symbiosis.

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Early events of vesicular–arbuscular mycorrhiza formation on Ri T‐DNA transformed roots

Cited by 735 publications

References 20 publications

The spatial expression patterns of a phosphate transporter (MtPT1) from Medicago truncatula indicate a role in phosphate transport at the root/soil interface

The spatial expression patterns of a phosphate transporter (MtPT1) from Medicago truncatula indicate a role in phosphate transport at the root/soil interface

The expression of GintPT, the phosphate transporter of Rhizophagus irregularis, depends on the symbiotic status and phosphate availability

The exudate from an arbuscular mycorrhizal fungus induces nitric oxide accumulation in Medicago truncatula roots

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