Abstract
Plants have evolved pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) to protect themselves from infection by diverse pathogens. Avirulence (Avr) effectors that trigger plant ETI as a result of recognition by plant resistance (R) gene products have been identified in many plant pathogenic oomycetes and fungi. However, the virulence functions of oomycete and fungal Avr effectors remain largely unknown. Here, we combined bioinformatics and genetics to identify Avr3b, a new Avr gene from Phytophthora sojae, an oomycete pathogen that causes soybean root rot. Avr3b encodes a secreted protein with the RXLR host-targeting motif and C-terminal W and Nudix hydrolase motifs. Some isolates of P. sojae evade perception by the soybean R gene Rps3b through sequence mutation in Avr3b and lowered transcript accumulation. Transient expression of Avr3b in Nicotiana benthamiana increased susceptibility to P. capsici and P. parasitica, with significantly reduced accumulation of reactive oxygen species (ROS) around invasion sites. Biochemical assays confirmed that Avr3b is an ADP-ribose/NADH pyrophosphorylase, as predicted from the Nudix motif. Deletion of the Nudix motif of Avr3b abolished enzyme activity. Mutation of key residues in Nudix motif significantly impaired Avr3b virulence function but not the avirulence activity. Some Nudix hydrolases act as negative regulators of plant immunity, and thus Avr3b might be delivered into host cells as a Nudix hydrolase to impair host immunity. Avr3b homologues are present in several sequenced Phytophthora genomes, suggesting that Phytophthora pathogens might share similar strategies to suppress plant immunity.
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Claims 11
Claim · model-written summary
Avr3b was identified as a new gene from the soybean root rot pathogen.
- Taxon
- soybean
Glycine maxe0 - Interactor
- Phytophthora sojaePhytophthora sojaee0pathogen
- Gene
- Avr3be0
- Outcome
- a new Avr genee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“identify Avr3b, a new Avr gene from Phytophthora sojae, an oomycete pathogen that causes soybean root rot”
Claim · model-written summary
Avr3b encodes a secreted protein with RXLR, W and Nudix motifs.
- Taxon
- soybeanGlycine maxe1
- Gene
- Avr3be0
- Outcome
- secreted protein with the RXLR host-targeting motif and C-terminal W and Nudix hydrolase motifse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Avr3b encodes a secreted protein with the RXLR host-targeting motif and C-terminal W and Nudix hydrolase motifs”
e1“soybean root rot”
Claim · model-written summary
Some P. sojae isolates evade soybean Rps3b recognition through Avr3b mutation and lower transcripts.
- Taxon
- soybeanGlycine maxe0
- Interactor
- P. sojaePhytophthora sojaee0pathogen
- Gene
- Rps3be0
- Outcome
- evade perceptione0
- Qualifier
- sequence mutation in Avr3b and lowered transcript accumulatione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Some isolates of P. sojae evade perception by the soybean R gene Rps3b through sequence mutation in Avr3b and lowered transcript accumulation”
Claim · model-written summary
Transient Avr3b expression increased Nicotiana benthamiana susceptibility to P. capsici.
- Taxon
- Nicotiana benthamiana
Nicotiana benthamianae0 - Treatment
- Transient expression of Avr3be0
- Interactor
- P. capsici
.jpg?width=60)
Phytophthora capsicie0pathogen - Gene
- Avr3be0
- Outcome
- susceptibility to P. capsicie0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Transient expression of Avr3b in Nicotiana benthamiana increased susceptibility to P. capsici and P. parasitica”
Claim · model-written summary
Transient Avr3b expression increased Nicotiana benthamiana susceptibility to P. parasitica.
- Taxon
- Nicotiana benthamianaNicotiana benthamianae0
- Treatment
- Transient expression of Avr3be0
- Interactor
- P. parasitica
Phytophthora nicotianaee0pathogen - Gene
- Avr3be0
- Outcome
- susceptibilitye0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transient expression of Avr3b in Nicotiana benthamiana increased susceptibility to P. capsici and P. parasitica”
Claim · model-written summary
Avr3b expression reduced ROS accumulation around invasion sites.
- Taxon
- Nicotiana benthamianaNicotiana benthamianae0
- Treatment
- Transient expression of Avr3be0
- Interactor
- P. capsiciPhytophthora capsicie0pathogen
- Gene
- Avr3be0
- Outcome
- accumulation of reactive oxygen species (ROS)e0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transient expression of Avr3b in Nicotiana benthamiana increased susceptibility to P. capsici and P. parasitica, with significantly reduced accumulation of reactive oxygen species (ROS) around invasion sites”
Claim · model-written summary
Biochemical assays identified Avr3b as an ADP-ribose/NADH pyrophosphorylase.
- Taxon
- soybeanGlycine maxe1
- Gene
- Avr3be0
- Outcome
- ADP-ribose/NADH pyrophosphorylasee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biochemical assays confirmed that Avr3b is an ADP-ribose/NADH pyrophosphorylase”
e1“soybean root rot”
Claim · model-written summary
Deleting the Avr3b Nudix motif abolished enzyme activity.
- Taxon
- soybeanGlycine maxe1
- Treatment
- Deletion of the Nudix motif of Avr3be0
- Gene
- Avr3be0
- Outcome
- enzyme activitye0
- Direction
- abolishede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Deletion of the Nudix motif of Avr3b abolished enzyme activity”
e1“soybean root rot”
Claim · model-written summary
Mutating key Nudix residues significantly impaired Avr3b virulence function.
- Taxon
- soybeanGlycine maxe1
- Treatment
- Mutation of key residues in Nudix motife0
- Gene
- Avr3be0
- Outcome
- Avr3b virulence functione0
- Direction
- impairede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Mutation of key residues in Nudix motif significantly impaired Avr3b virulence function but not the avirulence activity”
e1“soybean root rot”
Claim · model-written summary
Mutating key Nudix residues did not impair Avr3b avirulence activity.
- Taxon
- soybeanGlycine maxe1
- Treatment
- Mutation of key residues in Nudix motife0
- Gene
- Avr3be0
- Outcome
- avirulence activitye0
- Direction
- note0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Mutation of key residues in Nudix motif significantly impaired Avr3b virulence function but not the avirulence activity”
e1“soybean root rot”
Claim · model-written summary
Avr3b homologues occur in several sequenced Phytophthora genomes.
- Taxon
- soybeanGlycine maxe1
- Gene
- Avr3b homologuese0
- Outcome
- present in several sequenced Phytophthora genomese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Avr3b homologues are present in several sequenced Phytophthora genomes”
e1“soybean root rot”
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See all 37 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.