Plant Physiology Preview
Published on April 27, 2007; 10.1104/pp.107.097691
OPEN ACCESS ARTICLE
Received February 7, 2007
Accepted April 17, 2007
The GH3 Acyl Adenylase Family Member PBS3 Regulates Salicylic Acid-Dependent Defense Responses in Arabidopsis
K. Nobuta , R. A. Okrent , M. Stoutemyer , N. Rodibaugh , L. Kempema , M.C. Wildermuth *, and R.W. Innes
Department of Biology, Indiana University, Bloomington, IN 47405-7107, USA; and Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102, USA
* Corresponding author; email: wildermuth{at}nature.berkeley.edu.
The pbs3-1 mutant, identified in a screen for Arabidopsis thaliana mutants exhibiting enhanced susceptibility to the avirulent Pseudomonas syringae pathogen DC3000(avrPphB), also exhibits enhanced susceptibility to virulent Pseudomonas syringae strains, suggesting it may impact basal disease resistance. As induced salicylic acid (SA) is a critical mediator of basal resistance responses, free and glucose-conjugated SA levels were measured and expression of the SA-dependent pathogenesis related marker PR1 was assessed. Surprisingly, while accumulation of the salicylic acid glucoside (SAG) and expression of PR1 were dramatically reduced in the pbs3-1 mutant in response to P. syringae infection, free SA was elevated. However, in response to exogenous SA, the conversion of free SA to SAG and the induced expression of PR1 were similar in pbs3-1 and wild-type plants. Through positional cloning, complementation, and sequencing, we determined that the pbs3-1 mutant contains two point mutations in the C-terminal region of the protein encoded by At5g13320, resulting in non-conserved amino acid changes in highly conserved residues. Additional analyses with T-DNA insertion (pbs3-2) and transposon insertion (pbs3-3) mutations in At5g13320 confirmed our findings with pbs3-1. PBS3 (also referred to as GH3.12) is a member of the GH3 family of acyl-adenylate/thioester-forming enzymes. Characterized GH3 family members, such as JAR1, act as phytohormone-amino acid synthetases. Thus, our results suggest that amino acid conjugation plays a critical role in SA metabolism and induced defense responses with PBS3 acting upstream of SA, directly on SA, or on a competitive inhibitor of SA.
This article has been cited by other articles:
|
|
|
|
 
R. H. Dowen, J. L. Engel, F. Shao, J. R. Ecker, and J. E. Dixon
A Family of Bacterial Cysteine Protease Type III Effectors Utilizes Acylation-dependent and -independent Strategies to Localize to Plasma Membranes
J. Biol. Chem.,
June 5, 2009;
284(23):
15867 - 15879.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. E. Parker
The Quest for Long-Distance Signals in Plant Systemic Immunity
Sci. Signal.,
May 12, 2009;
2(70):
pe31 - pe31.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. R. Grant and J. D. G. Jones
Hormone (Dis)harmony Moulds Plant Health and Disease
Science,
May 8, 2009;
324(5928):
750 - 752.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. A. Okrent, M. D. Brooks, and M. C. Wildermuth
Arabidopsis GH3.12 (PBS3) Conjugates Amino Acids to 4-Substituted Benzoates and Is Inhibited by Salicylate
J. Biol. Chem.,
April 10, 2009;
284(15):
9742 - 9754.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
Z. Zhang, Q. Li, Z. Li, P. E. Staswick, M. Wang, Y. Zhu, and Z. He
Dual Regulation Role of GH3.5 in Salicylic Acid and Auxin Signaling during Arabidopsis-Pseudomonas syringae Interaction
Plant Physiology,
October 1, 2007;
145(2):
450 - 464.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
