Abstract
The mechanisms underpinning broad compatibility in root symbiosis are largely unexplored. The generalist root endophyte Piriformospora indica establishes long-lasting interactions with morphologically and biochemically different hosts, stimulating their growth, alleviating salt stress, and inducing local and systemic resistance to pathogens. Cytological studies and global investigations of fungal transcriptional responses to colonization of barley and Arabidopsis at different symbiotic stages identified host-dependent colonization strategies and host-specifically induced effector candidates. Here, we show that in Arabidopsis, P. indica establishes and maintains biotrophic nutrition within living epidermal cells, whereas in barley the symbiont undergoes a nutritional switch to saprotrophy that is associated with the production of secondary thinner hyphae in dead cortex cells. Consistent with a diversified trophic behavior and with the occurrence of nitrogen deficiency at the onset of saprotrophy in barley, fungal genes encoding hydrolytic enzymes and nutrient transporters were highly induced in this host but not in Arabidopsis. Silencing of the high-affinity ammonium transporter PiAMT1 gene, whose transcripts are accumulating during nitrogen starvation and in barley, resulted in enhanced colonization of this host, whereas it had no effect on the colonization of Arabidopsis. Increased levels of free amino acids and reduced enzymatic activity for the cell-death marker VPE (vacuolar-processing enzyme) in colonized barley roots coincided with an extended biotrophic lifestyle of P. indica upon silencing of PiAMT1. This suggests that PiAmt1 functions as a nitrogen sensor mediating the signal that triggers the in planta activation of the saprotrophic program. Thus, host-related metabolic cues affect the expression of P. indica's alternative lifestyles.
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Claims 8
Claim · model-written summary
P. indica maintains biotrophic nutrition in living Arabidopsis epidermal cells.
- Taxon
- Arabidopsis
Arabidopsise0 - Interactor
- P. indicaSerendipita indicae0symbiont
- Outcome
- biotrophic nutrition within living epidermal cellse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in Arabidopsis, P. indica establishes and maintains biotrophic nutrition within living epidermal cells”
Claim · model-written summary
In barley, the endophyte switches to saprotrophy with thinner hyphae in dead cortex cells.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaree0 - Interactor
- symbionte0symbiont
- Outcome
- nutritional switch to saprotrophye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“in barley the symbiont undergoes a nutritional switch to saprotrophy that is associated with the production of secondary thinner hyphae in dead cortex cells”
Claim · model-written summary
Fungal hydrolase and nutrient transporter genes were highly induced in barley but not Arabidopsis.
- Taxon
- barleyHordeum vulgaree0
- Interactor
- fungale0symbiont
- Outcome
- fungal genes encoding hydrolytic enzymes and nutrient transporterse0
- Direction
- highly inducede0
- Comparator
- Arabidopsise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Consistent with a diversified trophic behavior and with the occurrence of nitrogen deficiency at the onset of saprotrophy in barley, fungal genes encoding hydrolytic enzymes and nutrient transporters were highly induced in this host but not in Arabidopsis.”
Claim · model-written summary
PiAMT1 silencing enhanced endophyte colonization of barley.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- Silencing of the high-affinity ammonium transporter PiAMT1 genee0
- Gene
- PiAMT1e0
- Outcome
- colonization of this hoste0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Silencing of the high-affinity ammonium transporter PiAMT1 gene, whose transcripts are accumulating during nitrogen starvation and in barley, resulted in enhanced colonization of this host”
Claim · model-written summary
PiAMT1 silencing had no effect on Arabidopsis colonization.
- Taxon
- ArabidopsisArabidopsise0
- Outcome
- colonization of Arabidopsise0
- Direction
- no effecte0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it had no effect on the colonization of Arabidopsis”
Claim · model-written summary
Colonized barley roots had increased free amino acids with PiAMT1 silencing and extended biotrophy.
- Taxon
- barleyHordeum vulgaree0
- Interactor
- P. indicaSerendipita indicae0symbiont
- Gene
- PiAMT1e0
- Outcome
- levels of free amino acidse0
- Direction
- Increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased levels of free amino acids and reduced enzymatic activity for the cell-death marker VPE (vacuolar-processing enzyme) in colonized barley roots coincided with an extended biotrophic lifestyle of P. indica upon silencing of PiAMT1.”
Claim · model-written summary
Colonized barley roots had reduced VPE activity with PiAMT1 silencing and extended biotrophy.
- Taxon
- barleyHordeum vulgaree0
- Interactor
- P. indicaSerendipita indicae0symbiont
- Gene
- VPEe0
- Outcome
- enzymatic activity for the cell-death marker VPEe0
- Direction
- reducede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased levels of free amino acids and reduced enzymatic activity for the cell-death marker VPE (vacuolar-processing enzyme) in colonized barley roots coincided with an extended biotrophic lifestyle of P. indica upon silencing of PiAMT1.”
Claim · model-written summary
PiAmt1 may function as a nitrogen sensor triggering the saprotrophic program.
- Taxon
- barleyHordeum vulgaret0
- Gene
- PiAmt1e0
- Outcome
- activation of the saprotrophic programe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This suggests that PiAmt1 functions as a nitrogen sensor mediating the signal that triggers the in planta activation of the saprotrophic program.”
t0“saprotrophy in barley, fungal”
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See all 32 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.