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Published on: March 17, 2014
Secretion, modification, and regulation of Ax21
Sang-Wook Han1, Sang-Won Lee, Pamela C Ronald
1Department of Plant Pathology, University of California, One Shields Ave., Davis, CA 95616, USA.
Current Opinion in Microbiology
|January 18, 2011
Summary
Researchers found that a conserved microbial protein, Ax21, binds to the rice XA21 receptor. This interaction is crucial for innate immunity and may involve bacterial communication through quorum sensing (QS).
Area of Science:
- Plant-microbe interactions
- Innate immunity
- Microbial signaling
Background:
- Innate immunity relies on host receptors recognizing conserved microbial signatures.
- The function of microbe-derived molecules recognized by these receptors is largely unknown.
- The rice XA21 receptor recognizes a peptide from the bacterial protein Ax21.
Purpose of the Study:
- To investigate the biological function of Ax21, a conserved microbial protein.
- To explore the role of post-translational modification and regulatory systems in Ax21 perception.
- To determine if Ax21 acts as an inducer of bacterial quorum sensing (QS).
Main Methods:
- Demonstrated binding of the rice XA21 receptor to the AxY(S)22 peptide from Ax21.
- Hypothesized roles for RaxP, RaxQ, RaxST proteins in Ax21 modification.
- Hypothesized roles for RaxR/H and PhoP/Q two-component systems in Ax21 regulation.
Main Results:
- The rice XA21 receptor binds the AxY(S)22 peptide, derived from the conserved Ax21 protein.
- Ax21 is conserved across Xanthomonas species, Xylella fastidiosa, and Stenotrophomonas maltophilia.
- Ax21 is predicted to function as an inducer of quorum sensing (QS).
Conclusions:
- This study identifies a conserved microbial signature (Ax21) that binds a host receptor (XA21).
- This represents the first example of a microbial molecule binding a host receptor and inducing QS.
- Findings provide new insights into host-microbe interactions and microbial community signaling dynamics.
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