Abstract
BACKGROUND: Legumes form root nodules to house nitrogen fixing bacteria of the rhizobium family. The rhizobia are located intracellularly in the symbiotic nodule cells. In the legume Medicago truncatula these cells produce high amounts of Nodule-specific Cysteine-Rich (NCR) peptides which induce differentiation of the rhizobia into enlarged, polyploid and non-cultivable bacterial cells. NCRs are similar to innate immunity antimicrobial peptides. The NCR gene family is extremely large in Medicago with about 600 genes. RESULTS: Here we used the Medicago truncatula Gene Expression Atlas (MtGEA) and other published microarray data to analyze the expression of 334 NCR genes in 267 different experimental conditions. We find that all but five of these genes are expressed in nodules but in no other plant organ or in response to any other biotic interaction or abiotic stress tested. During symbiosis, none of the genes are induced by Nod factors. The NCR genes are activated in successive waves during nodule organogenesis, correlated with bacterial infection of the nodule cells and with a specific spatial localization of their transcripts from the apical to the proximal nodule zones. However, NCR expression is not associated with nodule senescence. According to their Shannon entropy, a measure expressing tissue specificity of gene expression, the NCR genes are among the most specifically expressed genes in M. truncatula. Moreover, when activated in nodules, their expression level is among the highest of all genes. CONCLUSIONS: Together, these data show that the NCR gene expression is subject to an extreme tight regulation and is only activated during nodule organogenesis in the polyploid symbiotic cells.
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Claims 8
Claim · model-written summary
All but five analyzed NCR genes were expressed in nodules only.
- Taxon
- Medicago truncatula
Medicago truncatulat0 - Organ / stage
- nodulese0
- Gene
- NCRt0
- Outcome
- expressed in nodules but in no other plant organe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“all but five of these genes are expressed in nodules but in no other plant organ or in response to any other biotic interaction or abiotic stress tested”
t0“NCR gene expression in Medicago truncatula”
Claim · model-written summary
Nod factors induced none of the NCR genes during symbiosis.
- Taxon
- Medicago truncatulaMedicago truncatulat0
- Treatment
- Nod factorse0
- Gene
- NCRt0
- Outcome
- none of the genes are inducede0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“During symbiosis, none of the genes are induced by Nod factors”
t0“NCR gene expression in Medicago truncatula”
Claim · model-written summary
NCR genes activated in successive waves during nodule organogenesis.
- Taxon
- Medicago truncatulaMedicago truncatulat0
- Organ / stage
- nodule organogenesise0
- Gene
- NCR genese0
- Outcome
- activated in successive wavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The NCR genes are activated in successive waves during nodule organogenesis”
t0“NCR gene expression in Medicago truncatula”
Claim · model-written summary
NCR activation correlated with bacterial infection of nodule cells.
- Taxon
- Medicago truncatulaMedicago truncatulat0
- Organ / stage
- nodule cellse0
- Gene
- NCRt0
- Outcome
- correlated with bacterial infectione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“correlated with bacterial infection of the nodule cells”
t0“NCR gene expression in Medicago truncatula”
Claim · model-written summary
NCR transcripts had specific localization from apical to proximal nodule zones.
- Taxon
- Medicago truncatulaMedicago truncatulat0
- Organ / stage
- apical to the proximal nodule zonese0
- Gene
- NCRt0
- Outcome
- specific spatial localization of their transcriptse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a specific spatial localization of their transcripts from the apical to the proximal nodule zones”
t0“NCR gene expression in Medicago truncatula”
Claim · model-written summary
NCR expression was not associated with nodule senescence.
- Taxon
- Medicago truncatulaMedicago truncatulat0
- Organ / stage
- nodule senescencee0
- Gene
- NCRe0
- Outcome
- NCR expressione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“NCR expression is not associated with nodule senescence”
t0“NCR gene expression in Medicago truncatula”
Claim · model-written summary
NCR genes ranked among the most tissue-specific expressed Medicago genes.
- Taxon
- M. truncatulaMedicago truncatulae0
- Gene
- NCR genese0
- Outcome
- most specifically expressed genese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the NCR genes are among the most specifically expressed genes in M. truncatula”
Claim · model-written summary
Activated NCR genes ranked among the highest expressed genes in nodules.
- Taxon
- Medicago truncatulaMedicago truncatulat0
- Organ / stage
- nodulese0
- Gene
- NCRt0
- Outcome
- expression level is among the highest of all genese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“when activated in nodules, their expression level is among the highest of all genes”
t0“NCR gene expression in Medicago truncatula”
The same questions in other papers
nodulation factor · molecular: expression · Medicago truncatula (barrel medic)Positive and negative results
4 papers in the same direction as this paper · 3 in the opposite direction
- positive
- positive
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See all 8 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.