Symplastic transport in soybean root nodules

Brown, Sharon; Oparka, Karl J.; Sprent, Janet I.; Walsh, Kerry B.

doi:10.1016/0038-0717(95)98609-r

Cited by 42 publications

(34 citation statements)

References 26 publications

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“…The presence of both enzymes in all cell types of the central tissue argues for Suc breakdown taking place in the cytosol of both uninfected and symbiosome-containing cells, where the products of Suc catabolism could provide the energy and carbon skeletons for atmospheric nitrogen reduction and assimilation. Cytosolic Suc breakdown in the central tissue of Lotus nodules would be further supported by symplastic distribution of Suc through the plasmodesmatal network that connects adjacent uninfected and uninfected-infected cells (Brown et al 1995;Abd-Alla et al 2000;Peiter and Schubert 2003) and up-regulation of the LjSUT4 gene, which codes for a nodule-enhanced member of the Suc transporter family (Flemetakis et al 2003b). Enhanced Suc catabolism in the cells of the central tissue could also account for starch biosynthesis and accumulation in the uninfected cells and other biosynthetic processes including cellulose and lipid biosynthesis.…”

Section: Discussionmentioning

confidence: 98%

Spatial and Temporal Organization of Sucrose Metabolism in Lotus japonicus Nitrogen-Fixing Nodules Suggests a Role for the Elusive Alkaline/Neutral Invertase

et al. 2006

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Symbiotic nitrogen fixation (SNF) in legume nodules is a highly energy demanding process, fuelled by plant-supplied carbohydrates mainly in the form of sucrose. In this study, we have combined molecular and biochemical approaches in order to study the spatial and temporal organisation of sucrose metabolism in nitrogen-fixing nodules of the model legume Lotus japonicus, with an emphasis on the neglected role of alkaline/neutral invertase. For this purpose, a full-length cDNA clone coding for an alkaline/neutral invertase isoform, termed LjInv1, was identified in a L. japonicus mature nodule cDNA libraries. Alkaline/neutral invertase activity was also found to be the predominant invertase activity in mature nodules. Real-time reverse-transcription polymerase chain reaction analysis was used in order to study the temporal expression patterns of LjInv1 in parallel with genes encoding acid invertase and sucrose synthase (SuSy) isoforms, and enzymes involved in the subsequent hexose partitioning including hexokinase, phosphoglucomutase (PGM) and phosphoglucose isomerase (PGI). The spatial organisation of sucrose metabolism was studied by in situ localisation of LjInv1 transcripts and alkaline/neutral invertase activity, and SuSy protein during nodule development. Furthermore, the spatial organisation of hexose metabolism was investigated by histochemical localisation of hexokinase, PGM and PGI activities in mature nodules. The results considered together indicate that alkaline/neutral invertase could contribute to both the Glc-1-P and Glc-6-P pools in nodules, fuelling both biosynthetic processes and SNF. Furthermore, transcript profiling analysis revealed that genes coding for hexokinase and putative plastidic PGM and PGI isoforms are upregulated during the early stages of nodule development, while the levels of transcripts corresponding to cytosolic PGM and PGI isoforms remained similar to uninfected roots, indicating a possible role of LjInv1 in producing hexoses for starch production and other biosynthetic processes in developing nodules.

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Section: Discussionmentioning

confidence: 98%

Spatial and Temporal Organization of Sucrose Metabolism in Lotus japonicus Nitrogen-Fixing Nodules Suggests a Role for the Elusive Alkaline/Neutral Invertase

et al. 2006

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“…Similarly, in a study by Streeter (1992), vacuum-infiltrated azure blue, fast green, and safranin did not penetrate beyond ''the single cell layer lacking intercellular spaces'' of G. max nodules. When the tracer lucifer yellow CH was injected into the central tissue of G. max nodules, its apoplastic spread was also stopped by the scleroid layer (Brown et al 1995). Infiltration studies thus indicate that the nodule endodermis and analogous structures appear to be major barriers for solutes.…”

Section: Development and Ultrastructure Of The Nodule Vascular Endodementioning

confidence: 97%

“…K Section approx. (Brown et al 1995;Abd-Alla et al 2000). The nodule vascular endodermis thus represents the interface between compartments for metabolism and long-distance transport, and may control solute exchange.…”

Section: Development and Ultrastructure Of The Nodule Vascular Endodementioning

confidence: 99%

Chemical composition and ultrastructure of broad bean ( Vicia faba L.) nodule endodermis in comparison to the root endodermis

Hartmann

Peiter

Koch³

et al. 2002

Planta

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Ultrastructure and development of apoplastic barriers within indeterminate root nodules formed by Vicia faba L. were examined by light and electron microscopy. The nodule outer cortex is separated from the inner cortex by a heavily suberized nodule endodermis, which matures in submeristematic regions and possesses suberin lamellae. Unsuberized passage cells are present near vascular strands, which are surrounded by a vascular endodermis attached on the inner side of the nodule endodermal cell walls. The vascular endodermis appears immediately below the meristematic apex in developmental state I (Casparian bands), gradually develops suberin lamellae, and attains developmental state II at the base of the nodule. For chemical analysis apoplastic barrier tissues were dissected after enzymatic digestion of non-impregnated tissues. Root epidermal and endodermal cell walls as well as nodule outer cortex could be isolated as pure fractions; nodule endodermal cell walls could not be separated from vascular endodermal cell walls and enclosed xylem vessels. Gas chromatography-flame ionization detection and gas chromatography-mass spectrometry were applied for quantitative and qualitative analysis of suberin and lignin in isolated cell walls of these tissues. The suberin content of isolated endodermal cell walls of nodules was approximately twice that of the root endodermal cell walls. The suberin content of the nodule outer cortex and root epidermal cell walls was less than one-tenth of that of the nodule endodermal cell wall. Substantial amounts of lignin could only be found in the nodule endodermal cell wall fraction. Organic solvent extracts of the isolated tissues revealed long-chain aliphatic acids, steroids, and triterpenoid structures of the lupeol type. Surprisingly, extract from the outer cortex consisted of 89% triterpenoids whereas extracts from all other cell wall isolates contained not more than 16% total triterpenoids. The results of ultrastructural and chemical composition are in good correspondence and underline the important role of the examined tissues as apoplastic barriers.

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“…Transporters are probably required for carrying the metabolites required for some of the steps involved in ureide synthesis (Zrenner et al, 2006) but none has been characterized in nodules so far. Ureides (allantoin and allantoic acid) are likely to move through the central infected zone of the nodule symplastically to the nodule cortex (Brown et al, 1995;Collier and Tegeder, 2012) but there is an apoplastic step in the cortex (Streeter 1992), possibly to pass the cortical endodermis. Ureide transporters on the plasma membrane of nodule cortex and vascular endodermal cells mediate the transport of ureides to the xylem for export from the nodules (Pélissier et al, 2004;Collier and Tegeder, 2012).…”

Section: Transporters Required For Assimilation Of Fixed Nitrogenmentioning

confidence: 99%

Inorganic Nitrogen Uptake and Transport in Beneficial Plant Root-Microbe Interactions

Courty

Smith

Koegel

et al. 2014

Critical Reviews in Plant Sciences

127

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Symplastic transport in soybean root nodules

Cited by 42 publications

References 26 publications

Spatial and Temporal Organization of Sucrose Metabolism in Lotus japonicus Nitrogen-Fixing Nodules Suggests a Role for the Elusive Alkaline/Neutral Invertase

Spatial and Temporal Organization of Sucrose Metabolism in Lotus japonicus Nitrogen-Fixing Nodules Suggests a Role for the Elusive Alkaline/Neutral Invertase

Chemical composition and ultrastructure of broad bean ( Vicia faba L.) nodule endodermis in comparison to the root endodermis

Inorganic Nitrogen Uptake and Transport in Beneficial Plant Root-Microbe Interactions

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