Format

Send to

Choose Destination
See comment in PubMed Commons below
PLoS One. 2010 Dec 22;5(12):e15773. doi: 10.1371/journal.pone.0015773.

Detection and functional characterization of a 215 amino acid N-terminal extension in the Xanthomonas type III effector XopD.

Author information

1
Laboratoire des Interactions Plantes Micro-organismes, UMR CNRS-INRA 2594/441, Castanet Tolosan, France.

Abstract

During evolution, pathogens have developed a variety of strategies to suppress plant-triggered immunity and promote successful infection. In Gram-negative phytopathogenic bacteria, the so-called type III protein secretion system works as a molecular syringe to inject type III effectors (T3Es) into plant cells. The XopD T3E from the strain 85-10 of Xanthomonas campestris pathovar vesicatoria (Xcv) delays the onset of symptom development and alters basal defence responses to promote pathogen growth in infected tomato leaves. XopD was previously described as a modular protein that contains (i) an N-terminal DNA-binding domain (DBD), (ii) two tandemly repeated EAR (ERF-associated amphiphillic repression) motifs involved in transcriptional repression, and (iii) a C-terminal cysteine protease domain, involved in release of SUMO (small ubiquitin-like modifier) from SUMO-modified proteins. Here, we show that the XopD protein that is produced and secreted by Xcv presents an additional N-terminal extension of 215 amino acids. Closer analysis of this newly identified N-terminal domain shows a low complexity region rich in lysine, alanine and glutamic acid residues (KAE-rich) with high propensity to form coiled-coil structures that confers to XopD the ability to form dimers when expressed in E. coli. The full length XopD protein identified in this study (XopD(1-760)) displays stronger repression of the XopD plant target promoter PR1, as compared to the XopD version annotated in the public databases (XopD(216-760)). Furthermore, the N-terminal extension of XopD, which is absent in XopD(216-760), is essential for XopD type III-dependent secretion and, therefore, for complementation of an Xcv mutant strain deleted from XopD in its ability to delay symptom development in tomato susceptible cultivars. The identification of the complete sequence of XopD opens new perspectives for future studies on the XopD protein and its virulence-associated functions in planta.

PMID:
21203472
PMCID:
PMC3008746
DOI:
10.1371/journal.pone.0015773
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Public Library of Science Icon for PubMed Central
    Loading ...
    Support Center