Abstract
Protoplasts derived from cell suspensions of alfalfa (Medicago sativa L.) responded to treatment with fungal elicitor (FE) by an increase in endogenous chalcone synthase (CHS) activity but were unresponsive to reduced glutathione (GSH). Preexposure of protoplasts to polyethylene glycol and electroporation resulted in strong responsiveness to GSH but little change in responsiveness to FE. Protoplasts from suspension cultures which had been subcultured more than 12 times lost responsiveness to GSH, but not FE, as assessed by measuring expression of a chimeric gene containing a bean CHS promoter linked to a bacterial chloramphenicol acetyltransferase (CAT) reporter gene. In protoplasts in which putative cis-acting CHS promoter sequences had been coelectroporated in trans with the intact CHS promoter-CAT construct, the extent of CAT expression depended upon the elicitor used (FE or GSH), the age (number of times subcultured) of the cells from which the protoplasts were isolated, and the nature of the coelectroporated CHS promoter sequence. For example, a region of the CHS promoter from -326 to -141 behaved as a trans-activator when coelectroporated with the CAT construct into unelicited protoplasts isolated from newly initiated cell suspensions, but the same region acted as a trans-silencer in the same protoplasts in the presence of FE. This silencer activity was much reduced in GSH-treated protoplasts. The results suggest that there are differences in the signal transduction pathways for elicitation of CHS transcription by FE and GSH, which involve previously identified cis-elements in the CHS promoter. A wide range of structurally diverse biotic and abiotic agents (elicitors) have been shown to induce the expression of defense metabolism in plants (3, 4). This raises the obvious question of whether they act by a common mechanism. Of particular interest is the observation that reduced GSH acts as a strong elicitor of defense gene activation in intact suspension cells and protoplasts of bean and soybean (7, 13), selectively inducing gene expression in a manner similar to that observed in response to fungal elicitor preparations from the cell walls of the bean pathogen Colletotrichum lindemuthianum. A quantitatively major set of transcripts induced by GSH in cultured bean cells (13) and pea epicotyl tissue (14) encodes CHS2, a key regulatory enzyme in the biosynthesis of isoflavonoid phytoalexins in legume cells. CHS enzyme activity is also strongly induced by GSH in suspension cultured cells of the cactus Cephalocereus senilis (P. Paray, personal communication). CHS is encoded by a family of at least six genes in
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 9
Claim · model-written summary
Fungal elicitor increased chalcone synthase activity in alfalfa protoplasts.
- Taxon
- alfalfa
Medicago sativae0 - Organ / stage
- protoplastse0
- Treatment
- fungal elicitor (FE)e0
- Outcome
- chalcone synthase (CHS) activitye0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Protoplasts derived from cell suspensions of alfalfa (Medicago sativa L.) responded to treatment with fungal elicitor (FE) by an increase in endogenous chalcone synthase (CHS) activity but were unresponsive to reduced glutathione (GSH)”
Claim · model-written summary
Alfalfa protoplasts were unresponsive to reduced glutathione in chalcone synthase activity.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- reduced glutathione (GSH)e0
- Outcome
- chalcone synthase (CHS) activitye0
- Direction
- no_changeinferrede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Protoplasts derived from cell suspensions of alfalfa (Medicago sativa L.) responded to treatment with fungal elicitor (FE) by an increase in endogenous chalcone synthase (CHS) activity but were unresponsive to reduced glutathione (GSH)”
Claim · model-written summary
Protoplasts from suspension cultures subcultured more than 12 times lost responsiveness to glutathione but not to fungal elicitor.
- Taxon
- alfalfaMedicago sativae0
- Organ / stage
- suspension culturese1
- Treatment
- subcultured more than 12 timese1
- Outcome
- responsiveness to GSHe1
- Direction
- loste1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Protoplasts derived from cell suspensions of alfalfa (Medicago sativa L.) responded to treatment with fungal elicitor (FE) by an increase in endogenous chalcone synthase (CHS) activity but were unresponsive to reduced glutathione (GSH)”
e1“Protoplasts from suspension cultures which had been subcultured more than 12 times lost responsiveness to GSH, but not FE”
Claim · model-written summary
Preexposure to polyethylene glycol and electroporation increased responsiveness of alfalfa protoplasts to glutathione.
- Taxon
- alfalfaMedicago sativae0
- Organ / stage
- protoplastse1
- Treatment
- polyethylene glycol and electroporatione1
- Outcome
- responsiveness to GSHe1
- Direction
- increaseinferrede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Protoplasts derived from cell suspensions of alfalfa (Medicago sativa L.) responded to treatment with fungal elicitor (FE) by an increase in endogenous chalcone synthase (CHS) activity but were unresponsive to reduced glutathione (GSH)”
e1“Preexposure of protoplasts to polyethylene glycol and electroporation resulted in strong responsiveness to GSH but little change in responsiveness to FE”
Claim · model-written summary
Preexposure to polyethylene glycol and electroporation caused little change in responsiveness of alfalfa protoplasts to fungal elicitor.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- polyethylene glycol and electroporatione1
- Outcome
- responsiveness to FEe1
- Direction
- little changee1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Protoplasts derived from cell suspensions of alfalfa (Medicago sativa L.) responded to treatment with fungal elicitor (FE) by an increase in endogenous chalcone synthase (CHS) activity but were unresponsive to reduced glutathione (GSH)”
e1“Preexposure of protoplasts to polyethylene glycol and electroporation resulted in strong responsiveness to GSH but little change in responsiveness to FE”
Claim · model-written summary
A chimeric CHS promoter region from -326 to -141 trans-activated CAT expression in unelicited protoplasts from newly initiated suspensions.
- Taxon
- alfalfaMedicago sativae0
- Organ / stage
- unelicited protoplastse1
- Treatment
- a region of the CHS promoter from -326 to -141e1
- Outcome
- CAT expressione2
- Direction
- increaseinferrede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Protoplasts derived from cell suspensions of alfalfa (Medicago sativa L.) responded to treatment with fungal elicitor (FE) by an increase in endogenous chalcone synthase (CHS) activity but were unresponsive to reduced glutathione (GSH)”
e1“a region of the CHS promoter from -326 to -141 behaved as a trans-activator when coelectroporated with the CAT construct into unelicited protoplasts isolated from newly initiated cell suspensions, but the same region acted as a trans-silencer in the same protoplasts in the presence of FE”
e2“the extent of CAT expression depended upon the elicitor used”
Claim · model-written summary
The same CHS promoter region acted as a trans-silencer of CAT expression in the presence of fungal elicitor.
- Taxon
- alfalfaMedicago sativae0
- Treatment
- a region of the CHS promoter from -326 to -141e1
- Outcome
- CAT expressione2
- Direction
- decreaseinferrede1
- Qualifier
- in the presence of FEe1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Protoplasts derived from cell suspensions of alfalfa (Medicago sativa L.) responded to treatment with fungal elicitor (FE) by an increase in endogenous chalcone synthase (CHS) activity but were unresponsive to reduced glutathione (GSH)”
e1“a region of the CHS promoter from -326 to -141 behaved as a trans-activator when coelectroporated with the CAT construct into unelicited protoplasts isolated from newly initiated cell suspensions, but the same region acted as a trans-silencer in the same protoplasts in the presence of FE”
e2“the extent of CAT expression depended upon the elicitor used”
Claim · model-written summary
Silencer activity of the CHS promoter region was much reduced in glutathione-treated protoplasts.
- Taxon
- alfalfaMedicago sativae0
- Organ / stage
- protoplastse1
- Treatment
- GSH-treatede1
- Outcome
- silencer activitye1
- Direction
- much reducede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Protoplasts derived from cell suspensions of alfalfa (Medicago sativa L.) responded to treatment with fungal elicitor (FE) by an increase in endogenous chalcone synthase (CHS) activity but were unresponsive to reduced glutathione (GSH)”
e1“This silencer activity was much reduced in GSH-treated protoplasts”
Claim · model-written summary
Differences in signal transduction pathways are suggested to explain elicitation of CHS transcription by fungal elicitor versus glutathione.
- Taxon
- alfalfaMedicago sativae0
- Gene
- CHSe1
- Outcome
- elicitation of CHS transcriptione1
- Qualifier
- differences in the signal transduction pathwayse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Protoplasts derived from cell suspensions of alfalfa (Medicago sativa L.) responded to treatment with fungal elicitor (FE) by an increase in endogenous chalcone synthase (CHS) activity but were unresponsive to reduced glutathione (GSH)”
e1“The results suggest that there are differences in the signal transduction pathways for elicitation of CHS transcription by FE and GSH”
The same questions in other papers
glutathione · molecular: metabolites · Medicago sativa (alfalfa)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- positive
- no effect
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.