Abstract
Magnaporthe oryzae is the causal agent of rice blast disease, a major threat to global food security. Although M. oryzae infects a broad range of monocotyledonous plants, it fails to colonize dicot species such as Nicotiana benthamiana, offering a useful system to investigate nonhost resistance (NHR). In this study, we characterized the immune responses of N. benthamiana to M. oryzae by profiling defense-related gene expression, analyzing fungal invasion, and functionally dissecting key immune components. Time-course expression analyses revealed sustained upregulation of NbBAK1, NbEAS, NbWRKY22, and NbPR1, alongside dynamic regulation of NbCYP71D20 and NbSGT1. Virus-induced gene silencing demonstrated that silencing of NbSGT1, but not NbEAS or NbBAK1, significantly enhanced fungal colonization. Furthermore, salicylic acid (SA)-deficient NahG plants exhibited increased susceptibility, suggesting that SA and SGT1-dependent immunity synergistically contribute to NHR. Visualization of infection using a GFP-expressing fungal strain confirmed that suppression of SGT1 and SA signaling facilitated hyphal expansion into adjacent host cells. High-throughput screening of 179 M. oryzae candidate effectors revealed that 70 induced hypersensitive response-like cell death in N. benthamiana, a response that was abrogated by NbSGT1 silencing. These findings collectively demonstrate that SA signaling and SGT1-dependent effector-triggered immunity are critical barriers against M. oryzae invasion and highlight the potential of nonhost immune components as resources for engineering durable resistance in crops.
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Claims 8
Claim · model-written summary
Defense genes showed sustained upregulation after M. oryzae challenge.
- Taxon
- Nicotiana benthamiana
Nicotiana benthamianat0 - Gene
- NbBAK1, NbEAS, NbWRKY22, and NbPR1e0
- Outcome
- sustained upregulatione0
- Direction
- upregulatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Time-course expression analyses revealed sustained upregulation of NbBAK1, NbEAS, NbWRKY22, and NbPR1”
t0“Nicotiana benthamiana”
Claim · model-written summary
NbCYP71D20 and NbSGT1 showed dynamic regulation.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Gene
- NbCYP71D20 and NbSGT1e0
- Outcome
- dynamic regulatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“alongside dynamic regulation of NbCYP71D20 and NbSGT1”
t0“Nicotiana benthamiana”
Claim · model-written summary
Silencing NbSGT1 significantly enhanced fungal colonization.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Treatment
- silencing of NbSGT1e0
- Interactor
- Magnaporthe oryzae
Pyricularia oryzaet1pathogen - Gene
- NbSGT1e0
- Outcome
- fungal colonizatione0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“silencing of NbSGT1, but not NbEAS or NbBAK1, significantly enhanced fungal colonization”
t0“Nicotiana benthamiana”
t1“Magnaporthe oryzae”
Claim · model-written summary
Silencing NbEAS or NbBAK1 did not significantly enhance fungal colonization.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Treatment
- NbEAS or NbBAK1e0
- Outcome
- fungal colonizatione0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“silencing of NbSGT1, but not NbEAS or NbBAK1, significantly enhanced fungal colonization”
t0“Nicotiana benthamiana”
Claim · model-written summary
SA-deficient NahG plants showed increased susceptibility.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Material
- NahG plantse0
- Compound
- salicylic acid (SA)e0
- Outcome
- susceptibilitye0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“salicylic acid (SA)-deficient NahG plants exhibited increased susceptibility”
t0“Nicotiana benthamiana”
Claim · model-written summary
Suppression of SGT1 and SA signaling facilitated hyphal expansion into adjacent host cells.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Treatment
- suppression of SGT1 and SA signalinge0
- Interactor
- Magnaporthe oryzaePyricularia oryzaet1pathogen
- Outcome
- hyphal expansion into adjacent host cellse0
- Direction
- facilitatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“suppression of SGT1 and SA signaling facilitated hyphal expansion into adjacent host cells”
t0“Nicotiana benthamiana”
t1“Magnaporthe oryzae”
Claim · model-written summary
Seventy of 179 candidate M. oryzae effectors induced hypersensitive response-like cell death.
- Taxon
- N. benthamianaNicotiana benthamianae0
- Interactor
- M. oryzaePyricularia oryzaee0pathogent1
- Outcome
- hypersensitive response-like cell deathe0
- Value
- 70e0
- Qualifier
- 179 M. oryzae candidate effectorse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“screening of 179 M. oryzae candidate effectors revealed that 70 induced hypersensitive response-like cell death in N. benthamiana”
t1“Pathogen”
Claim · model-written summary
NbSGT1 silencing abrogated effector-induced cell death.
- Taxon
- Nicotiana benthamianaNicotiana benthamianat0
- Treatment
- NbSGT1 silencinge0
- Outcome
- responsee0
- Direction
- abrogatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a response that was abrogated by NbSGT1 silencing”
t0“Nicotiana benthamiana”
The same questions in other papers
loss of function · Pyricularia oryzae · Nicotiana benthamianaResults agree
1 paper in the same direction as this paper
- negative
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.