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Updated: May 30, 2026
10:07
Identification of Post-translational Modifications of Plant Protein Complexes
Published on: February 22, 2014
Hyaloperonospora arabidopsidis ATR1 effector is a repeat protein with distributed recognition surfaces
Seemay Chou1, Ksenia V Krasileva, James M Holton
1Department of Cell and Molecular Biology, University of California, Berkeley, CA 94720, USA.
Summary
The oomycete effector ATR1 from Hyaloperonospora arabidopsidis has a unique structure that helps it evade plant immunity. Its evolution allows it to escape host detection and gain new virulence functions.
Area of Science:
- Plant-pathogen interactions
- Molecular plant pathology
- Structural biology
Background:
- Hyaloperonospora arabidopsidis (Hpa) is an oomycete pathogen that infects Arabidopsis thaliana.
- The Hpa effector ATR1 is recognized by the Arabidopsis RPP1 immune receptor, triggering a defense response.
- Understanding effector-receptor interactions is crucial for developing disease-resistant crops.
Purpose of the Study:
- To determine the crystal structure of the Hpa effector ATR1.
- To investigate the molecular basis of ATR1 recognition by the Arabidopsis RPP1 immune receptor.
- To understand the evolutionary mechanisms of effector diversification and host immune evasion.
Main Methods:
- X-ray crystallography to determine the 3D structure of ATR1.
- In planta assays to evaluate the function of ATR1 surface polymorphisms.
- Structural comparisons with known protein folds.
Main Results:
- ATR1 exhibits a novel, elongated, all-helical, two-domain structure, distinct from previously characterized folds.
- A tandemly duplicated, five-helix motif in the C-terminal domain facilitates rapid structural diversification.
- Multiple distinct protein surfaces of ATR1 are involved in RPP1 recognition, allowing for immune evasion through polymorphisms.
- Gain-of-recognition mutants revealed that multiple amino acid substitutions and additive effects of polymorphisms are required for recognition.
Conclusions:
- ATR1 is a modular repeat protein from an ancient oomycete effector family.
- The unique structure and modularity of ATR1 contribute to its rapid evolution and ability to escape host immune detection.
- ATR1's adaptability allows it to acquire diverse virulence functions, posing a significant challenge to plant immunity.
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