Abstract
Extracellular lipo-oligosaccharides of Rhizobium, known as Nod factors, play a key role in the molecular signal exchange which leads to the specific nitrogen-fixing symbiotic association between the soil microbe and its host legume. The biological activity of Nod factors and their perception by the host plant during the earliest stages of the Rhizobium/legume interaction have been studied using transgenic alfalfa carrying a fusion between the promoter of the early nodulin gene MtENOD12 and the beta-glucuronidase (GUS) reporter gene. Histochemical staining has shown that GUS accumulates specifically in the differentiating root epidermis, prior to and during root hair emergence, within 2-3 h following the addition of purified Rhizobium meliloti Nod factors. This precocious transcriptional activation of the MtENOD12 gene, reminiscent of that observed after inoculation with intact Rhizobium, implies that the Nod factor signal can be perceived at a developmental stage preceding root hair formation. GUS activity can be detected following treatment with a wide range of R. meliloti Nod factor concentrations down to 10(-13) M, and furthermore, this rapid response to the bacterial elicitor appears to be non-systemic. Significantly, MtENOD12-GUS expression is not observed after inoculation with a R. meliloti nodH mutant which synthesizes exclusively non-sulphated Nod factors. Indeed purified Nod factors which lack the sulphate substituent are approximately 1000-fold less active than their sulphated counterparts. Thus, the triggering of ENOD12 transcription in the alfalfa root epidermis is a rapid molecular response which is subject to the same host-specificity determinant (Nod factor sulphation) that governs the interaction between alfalfa and its bacterial symbiont.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 5
Claim · model-written summary
Purified Rhizobium meliloti Nod factors triggered GUS accumulation specifically in differentiating root epidermis within 2-3 h.
- Taxon
- alfalfa
Medicago sativae0 - Material
- transgenic alfalfae0
- Organ / stage
- differentiating root epidermise1
- Treatment
- purified Rhizobium meliloti Nod factorse1
- Interactor
- Rhizobium meliloti
Sinorhizobium melilotie1symbiont - Gene
- MtENOD12e0
- Outcome
- GUSe1
- Direction
- accumulatese1
- Qualifier
- within 2-3 he1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic alfalfa carrying a fusion between the promoter of the early nodulin gene MtENOD12 and the beta-glucuronidase (GUS) reporter gene”
e1“Histochemical staining has shown that GUS accumulates specifically in the differentiating root epidermis, prior to and during root hair emergence, within 2-3 h following the addition of purified Rhizobium meliloti Nod factors”
Claim · model-written summary
GUS activity was detectable after treatment with R. meliloti Nod factor concentrations down to 10(-13) M.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- R. meliloti Nod factor concentrationse1
- Interactor
- R. melilotiSinorhizobium melilotie1symbiont
- Outcome
- GUS activitye1
- Value
- 10(-13) Me1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic alfalfa carrying a fusion between the promoter of the early nodulin gene MtENOD12 and the beta-glucuronidase (GUS) reporter gene”
e1“GUS activity can be detected following treatment with a wide range of R. meliloti Nod factor concentrations down to 10(-13) M”
Claim · model-written summary
The rapid response to the bacterial elicitor appears to be non-systemic.
- Taxon
- alfalfaMedicago sativae0
- Outcome
- rapid response to the bacterial elicitore1
- Qualifier
- non-systemice1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic alfalfa carrying a fusion between the promoter of the early nodulin gene MtENOD12 and the beta-glucuronidase (GUS) reporter gene”
e1“this rapid response to the bacterial elicitor appears to be non-systemic”
Claim · model-written summary
MtENOD12-GUS expression is not observed after inoculation with a R. meliloti nodH mutant that makes only non-sulphated Nod factors.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- inoculation with a R. meliloti nodH mutante1
- Interactor
- R. melilotiSinorhizobium melilotie1symbiont
- Gene
- MtENOD12e1
- Outcome
- MtENOD12-GUS expressione1
- Direction
- not observede1
- Qualifier
- synthesizes exclusively non-sulphated Nod factorse1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic alfalfa carrying a fusion between the promoter of the early nodulin gene MtENOD12 and the beta-glucuronidase (GUS) reporter gene”
e1“Significantly, MtENOD12-GUS expression is not observed after inoculation with a R. meliloti nodH mutant which synthesizes exclusively non-sulphated Nod factors”
Claim · model-written summary
Nod factors lacking the sulphate substituent are approximately 1000-fold less active than sulphated Nod factors.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- purified Nod factors which lack the sulphate substituente1
- Outcome
- activee1
- Direction
- lesse1
- Value
- approximately 1000-folde1
- Comparator
- sulphated counterpartse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transgenic alfalfa carrying a fusion between the promoter of the early nodulin gene MtENOD12 and the beta-glucuronidase (GUS) reporter gene”
e1“purified Nod factors which lack the sulphate substituent are approximately 1000-fold less active than their sulphated counterparts”
The same questions in other papers
Sinorhizobium meliloti · molecular: expression · Medicago sativa (alfalfa)Positive and negative results
3 papers in the same direction as this paper · 1 in the opposite direction
- negative
- positive
- positive
1 paper more in this group
See all 5 papers →nodulation factor · molecular: expression · Medicago sativa (alfalfa)Results agree
2 papers in the same direction as this paper
- positive
- positive
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.