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

Flemetakis, Emmanouil; Efrose, Rodica; Ott, Thomas; Stedel, Catalina; Aivalakis, Georgios; Udvardi, Michael K.; Katinakis, Panagiotis

doi:10.1007/s11103-006-9003-4

Cited by 39 publications

(40 citation statements)

References 78 publications

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“…5D). High levels of transcript of this gene in nodules were also reported by Flemetakis et al (2006). LjSUS4 was found only in flowers, at very low levels, and does not contribute significantly to the overall LjSUS mRNA content.…”

Section: Discussionsupporting

confidence: 53%

“…We also examined the morphology of the wild-type and sus nodules at the peak of LjSUS3 expression (Flemetakis et al, 2006), but found no sign of early senescence at that stage (data not shown). We also counted the number of functioning and senescent nodules of wild-type and sus mutants and again found no difference between them (Table V).…”

Section: Discussionmentioning

confidence: 97%

“…A role for noduleenhanced alkaline/neutral invertase, LjINV1, in nodule function has been proposed by Flemetakis et al (2006). Their developmental study showed a slight (2-fold) increase in LjINV transcript levels in nodules up to 10 dpi and increased LjSUS3 transcript level from 14 to 21 dpi.…”

Section: Discussionmentioning

confidence: 99%

“…Supporting this, acid invertase transcripts have not been identified from nodule EST libraries of Lotus japonicus and only very low acid invertase activities have been detected in this organ (Flemetakis et al, 2006). There is no consensus, however, about the relative importance of alkaline/neutral invertase and Suc synthase in nodule metabolism.…”

mentioning

confidence: 99%

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TILLING Mutants of Lotus japonicus Reveal That Nitrogen Assimilation and Fixation Can Occur in the Absence of Nodule-Enhanced Sucrose Synthase

Horst

Welham

Kelly³

et al. 2007

Plant Physiology

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In all plant species studied to date, sucrose synthase occurs as multiple isoforms. The specific functions of the different isoforms are for the most part not clear. Six isoforms of sucrose synthase have been identified in the model legume Lotus japonicus, the same number as in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa). The genes encoding these isoforms are differentially expressed in all plant organs examined, although one, LjSUS4, is only expressed in flowers. LjSUS1 is the most highly expressed in all plant organs tested, except root nodules, where LjSUS3 accounts for more than 60% of the total SUS transcripts. One gene, LjSUS2, produces two transcripts due to alternative splicing, a feature not observed in other species to date. We have isolated plants carrying ethyl methanesulfonate-induced mutations in several SUS genes by targeting-induced local lesions in genomes reverse genetics and examined the effect of null alleles of two genes, LjSUS1 and LjSUS3, on nodule function. No differences were observed between the mutants and wild-type plants under glasshouse conditions, but there was evidence for a nitrogenstarvation phenotype in the sus3-1 mutant and severe impairment of growth in the sus1-1/sus3-1 double mutant under specific environmental conditions. Nodules of sus3-1 mutant plants retained a capacity for nitrogen fixation under all conditions. Thus, nitrogen fixation can occur in L. japonicus nodules even in the absence of LjSUS3 (the major nodule-induced isoform of SUS), so LjSUS1 must also contribute to the maintenance of nitrogen assimilation.

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Section: Discussionsupporting

confidence: 53%

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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TILLING Mutants of Lotus japonicus Reveal That Nitrogen Assimilation and Fixation Can Occur in the Absence of Nodule-Enhanced Sucrose Synthase

Horst

Welham

Kelly³

et al. 2007

Plant Physiology

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“…In nodules, Suc cleavage is catalyzed by either SucS or alkaline Inv, but presumably not by apoplastic Inv (Peiter and Schubert, 2003). In soybean (Glycine max), Lotus japonicus, and M. truncatula root nodules, an alkaline/neutral Inv gene with a nodule-enhanced transcription was described, indicating a Suc-degrading function for those Inv in developing root nodules (Flemetakis et al, 2006;Tesfaye et al, 2006). By contrast, SucS is considered to be principally responsible for Suc degradation in mature nodules (Anthon and Emmerich, 1990;Gordon et al, 1999).…”

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confidence: 99%

Antisense Repression of the Medicago truncatula Nodule-Enhanced Sucrose Synthase Leads to a Handicapped Nitrogen Fixation Mirrored by Specific Alterations in the Symbiotic Transcriptome and Metabolome

et al. 2007

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We analyzed the role of the sucrose (Suc) synthase MtSucS1 during nodulation of the model legume Medicago truncatula, integrating data for the developmental, transcriptional, and metabolic processes affected downstream of an impaired Suc cleavage in root nodules. To reduce carbohydrate supply to nodule tissues, transgenic plants expressing a p35S-driven MtSucS1-antisense fusion were constructed. These plants displayed an up to 90% reduction of MtSucS1 proteins in roots and nodules. Phenotypic studies of two independent MtSucS1-reduced lines demonstrated that only under conditions depending on nodulation, these plants appeared to be impaired in above-ground growth. Specifically plant height, shoot weight, leaf development, flowering, as well as seed maturation were reduced, and the efficiency of photosynthesis was affected. Concomitantly, a significantly enhanced root to shoot ratio with a marked increase in root tip numbers was observed. Root nodule formation was found retarded and the impaired nodulation was accompanied by a less efficient nitrogen (N) acquisition. The decreased total N content of MtSucS1-antisense lines and an enhanced carbon to N ratio in roots, nodules, and shoots correlated with the extent of MtSucS1 knockdown. On the level of transcription, effects of an MtSucS1 reduction were evident for genes representing important nodes of the nodule carbon and N metabolism, while metabolite profiling revealed significantly lower levels of amino acids and their derivatives particularly in strongly MtSucS1-reduced nodules. Our results support the model that nodule-enhanced Suc synthase 1 of the model legume M. truncatula is required for the establishment and maintenance of an efficient N-fixing symbiosis.

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Synthesis and Roles of Glutathione and Homoglutathione in the Nitrogen-Fixing Symbiosis

Boncompagni

Alloing

Mandon

et al. 2017

Glutathione in Plant Growth, Development, and Stress Tolerance

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

Cited by 39 publications

References 78 publications

TILLING Mutants of Lotus japonicus Reveal That Nitrogen Assimilation and Fixation Can Occur in the Absence of Nodule-Enhanced Sucrose Synthase

TILLING Mutants of Lotus japonicus Reveal That Nitrogen Assimilation and Fixation Can Occur in the Absence of Nodule-Enhanced Sucrose Synthase

Antisense Repression of the Medicago truncatula Nodule-Enhanced Sucrose Synthase Leads to a Handicapped Nitrogen Fixation Mirrored by Specific Alterations in the Symbiotic Transcriptome and Metabolome

Synthesis and Roles of Glutathione and Homoglutathione in the Nitrogen-Fixing Symbiosis

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