The Legume Root Nodule: From Symbiotic Nitrogen Fixation to Senescence

Dupont, Laurence; Alloing, Geneviève; Pierre, Olivier; Msehli, Sarra El; Hopkins, Julie; Hérouart, Didier; Frendo, Pierre

doi:10.5772/34438

Cited by 52 publications

(48 citation statements)

References 157 publications

(180 reference statements)

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“…However, during the termination of symbiosis and the senescence of infected cells, VPS proteins accumulate. In these cells, symbiosomes lose the ability to fix nitrogen and are transformed into lytic compartments that fuse and form vacuole-like units (Van de Velde et al, 2006;Dupont et al, 2012). These results show that the vacuolar fusion machinery controls symbiosome lysis.…”

Section: Discussionmentioning

confidence: 93%

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Adjustment of Host Cells for Accommodation of Symbiotic Bacteria: Vacuole Defunctionalization, HOPS Suppression, and TIP1g Retargeting in Medicago

et al. 2014

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In legume-rhizobia symbioses, the bacteria in infected cells are enclosed in a plant membrane, forming organelle-like compartments called symbiosomes. Symbiosomes remain as individual units and avoid fusion with lytic vacuoles of host cells. We observed changes in the vacuole volume of infected cells and thus hypothesized that microsymbionts may cause modifications in vacuole formation or function. To examine this, we quantified the volumes and surface areas of plant cells, vacuoles, and symbiosomes in root nodules of Medicago truncatula and analyzed the expression and localization of VPS11 and VPS39, members of the HOPS vacuole-tethering complex. During the maturation of symbiosomes to become N 2 -fixing organelles, a developmental switch occurs and changes in vacuole features are induced. For example, we found that expression of VPS11 and VPS39 in infected cells is suppressed and host cell vacuoles contract, permitting the expansion of symbiosomes. Trafficking of tonoplast-targeted proteins in infected symbiotic cells is also altered, as shown by retargeting of the aquaporin TIP1g from the tonoplast membrane to the symbiosome membrane. This retargeting appears to be essential for the maturation of symbiosomes. We propose that these alterations in the function of the vacuole are key events in the adaptation of the plant cell to host intracellular symbiotic bacteria.

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Section: Discussionmentioning

confidence: 93%

“…In senescing nodule cells, lytic compartments form de novo (Dupont et al, 2012). This likely requires a HOPS complex.…”

Section: The Hops Complex Is Temporarily Repressed In Young Nodule Inmentioning

confidence: 99%

Adjustment of Host Cells for Accommodation of Symbiotic Bacteria: Vacuole Defunctionalization, HOPS Suppression, and TIP1g Retargeting in Medicago

et al. 2014

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“…Alternatively, legumes such as pea (Pisum sativum L.) or clover (Trifolium spp.) form indeterminate nodules that have a permanent meristem and take on a more cylindrical shape (Dupont et al, 2012). The two primary bacterial genera that commonly colonize peanut nodules are Bradyrhizobium as well as Rhizobium (Nievas et al, 2012;Angelini et al, 2011).…”

mentioning

confidence: 99%

“…Peanut generally lacks root hairs on the taproot because the surface cell layers are shed, so nodules form at the base of lateral roots where rosette-type root hairs up to 4 mm in length are located (Akasaka et al, 1998). Peanut typically forms determinate type nodules (Akasaka et al, 1998) that are characterized by having no permanent meristem, a regular spherical shape, and a homogeneous central tissue within the nodule that is composed of tightly packed bacteroids responsible for the actual N fixation process (Desbrosses and Stougaard, 2011;Dupont et al, 2012). Alternatively, legumes such as pea (Pisum sativum L.) or clover (Trifolium spp.)…”

mentioning

confidence: 99%

“…The process of biological N fixation (BNF) involves symbiotic bacteria that reduce atmospheric N 2 to ammonia, a form of N that is available for plant nutrition (Nievas et al, 2012). The BNF process can account for as much as 65% of the N that is used in agriculture worldwide, with the largest quantity of fixed N originating from the symbiotic association between rhizobia and legumes (Dupont et al, 2012). For example, intercropped peanut has the capacity to provide over 10% of the total N that is accumulated in the accompanying crop during a growing season (Chu et al, 2004).…”

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confidence: 99%

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Visualization of Peanut Nodules and Seasonal Nodulation Pattern in Different Tillage Systems Using a Minirhizotron System

et al. 2015

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Nodulation is essential for providing the nitrogen (N) needs of peanut, but little is known about the time course of nodule development with soil depth in a field production system. A minirhizotron system allows for non-destructive, periodic digital imaging of identical locations in the crop root system in situ, including the associated nodules. Because the system allows imaging at the same location over time, individual nodule development and subsequent senescence can be followed throughout the growing season. To test the proof of concept for the use of a minirhizotron system to observe peanut nodule development, a case study was conducted in 2012 in Citra, FL in a sod-based production system managed with both conservation and conventional tillage at two different timings. Images were taken to a soil depth of 90 cm on four dates during the growing season, and nodule number, surface area, and senescence were determined. Most nodules occurred at depths spanning 5-30 cm with very few outside of this range; however, individual nodules were noted as deep as 90 cm. In this case study, tillage operation and timing had no impact on the total number of nodules produced, and the peak seasonal nodule number was formed relatively early in the season (9 July -61 days after planting) and stayed constant until harvest. Nodule number varied by soil depth with the majority of nodules formed in the 0-20 cm depth. Nodule surface area was impacted by tillage type with conservation tillage treatments having larger nodule size (average 2.6 mm 2 ) than nodules in conventional tillage (1.9 mm 2 ). Maximum nodule surface area was achieved by midseason on 1 August. This study gave a unique visual assessment of nodule development for field grown peanut over time and provided data that has rarely been reported. In addition, this study also illustrated that the minirhizotron technique could be successfully utilized in studies examining the development of nodules in peanut and would likely be applicable for similar studies in other legume crops.The nitrogen fixation process in peanut (Arachis hypogaea L.) is essential for providing nitrogen (N) for the crop throughout the season, as it delivers from 50-80% of the total N required by the plant (Boddey et al., 1990)

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Biotechnology approaches to overcome biotic and abiotic stress constraints in legumes

Babar

Zaidi

Azooz

et al. 2015

Legumes Under Environmental Stress

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The Legume Root Nodule: From Symbiotic Nitrogen Fixation to Senescence

Cited by 52 publications

References 157 publications

Adjustment of Host Cells for Accommodation of Symbiotic Bacteria: Vacuole Defunctionalization, HOPS Suppression, and TIP1g Retargeting in Medicago

Adjustment of Host Cells for Accommodation of Symbiotic Bacteria: Vacuole Defunctionalization, HOPS Suppression, and TIP1g Retargeting in Medicago

Visualization of Peanut Nodules and Seasonal Nodulation Pattern in Different Tillage Systems Using a Minirhizotron System

Biotechnology approaches to overcome biotic and abiotic stress constraints in legumes

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