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Title: Arabidopsis Abscisic Acid Repressor 1 is a susceptibility hub that interacts with multiple Pseudomonas syringae effectors
Summary

Pathogens secrete effector proteins into host cells to suppress host immunity and promote pathogen virulence, although many features at the molecular interface of host–pathogen interactions remain to be characterized. In a yeast two‐hybrid assay, we found that thePseudomonas syringaeeffector HopZ1a interacts with the Arabidopsis transcriptional regulator Abscisic Acid Repressor 1 (ABR1). Further analysis revealed that ABR1 interacts with multipleP. syringaeeffectors, suggesting that it may be targeted as a susceptibility hub. Indeed, loss‐of‐functionabr1mutants exhibit reduced susceptibility to a number ofP. syringaestrains. The ABR1 protein comprises a conserved APETALA2 (AP2) domain flanked by long regions of predicted structural disorder. We verified the DNA‐binding activity of the AP2 domain and demonstrated that the disordered domains act redundantly to enhance DNA binding and to facilitate transcriptional activation by ABR1. Finally, we compared gene expression profiles from wild‐type andabr1plants following inoculation withP. syringae, which suggested that the reduced susceptibility ofabr1mutants is due to the loss of a virulence target rather than an enhanced immune response. These data highlight ABR1 as a functionally important component at the host–pathogen interface.

 
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NSF-PAR ID:
10452409
Author(s) / Creator(s):
 ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
The Plant Journal
Volume:
105
Issue:
5
ISSN:
0960-7412
Page Range / eLocation ID:
p. 1274-1292
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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