The Xanthomonas Resource

Welcome to the Xanthomonas resource!

The genus Xanthomonas in the gamma subdivision of the Proteobacteria consists of 27 plant-associated species, many of which cause important diseases of crops and ornamentals. Individual species comprise multiple pathogenic variants (pathovars, pv.). Collectively, members of the genus cause disease on at least 124 monocot species and 268 dicot species, including fruit and nut trees, solanaceous and brassicaceous plants, and cereals (Hayward, 1993). They cause a variety of symptoms including necrosis, cankers, spots, and blight, and they affect a variety of plant parts including leaves, stems, and fruits (Leyns et al., 1984).

  1. Hayward AC (1993). The host of Xanthomonas. In: Xanthomonas; pp. 51-54. J.G. Swings and E.L. Civerolo (eds.); Chapman & Hall, London, United Kingdom.
  2. Leyns F, De Cleene M, Swings J, De Ley, J (1984). Bot. Rev. 50: 308-356.

2012, August 7:
New Xanthomonas genomes have been added to the GENOMES site:
2012, July 26:
Several new bioinformatic resources (databases and prediction algorithms for type III effectors) have been added to the TOOLS site.
2012, June 22:
Several Xanthomonas genomes which have been released in 2012 have been updated or added to the GENOMES site:
2012, January 10:
Several Xanthomonas genomes which have been released in 2011 have been updated or added to the GENOMES site:
2012, January 9:
If you are interested to follow the literature about Xanthomonas you might wish to follow the following Mendeley groups: (literature about Xanthomonas since 2009) (literature about taxonomy, diversity, typing and detection of Xanthomonas)
2012, January 1:
A new prototype of the website is available at Please use this site when you are interested in type III effectors. Little by little, we will add more genomes and type III effector families.
2011, June 20:
We offer an electronic newsletter with weekly updates on literature about Xanthomonas. For registration, please send an email to
2011, June 20:
Since May 2, 2011, the prototype version of is no longer supported/updated. We hope to release a new version soon.
2010, May 10:
Listing of open positions now available at the NEWS site under JOBS.
2009, December 10:
Modifications for XopO and XopAK: new information on HopK1, the homolog from Pst DC3000.
Modifications for XopW: the N terminus is probably one codon downstream for XOO_0037 and PXO_03356. Evidence: the initially predicted GTG start codon is not conserved in Xvv NCPPB702 [TTA=Leu].
2009, September 21:
X. campestris (vasicola) pv. musacearum NCPPB4381 ("Xvm") and X. campestris (vasicola) pv. vasculorum NCPPB702 ("Xvv") added to the GENOMES site and to the type III effector table. Few minor corrections within XopJ class and the P. syringae nomenclature. Few web resources (databases, Wiki) added to the TOOLS site.
2009, September 14:
Pseudomonas syringae pv. tabaci ATCC 11528 ("Pta") added to the type III effector table. Hits to the effectors XopE3, XopAA, and XopAM.
2009, September 7:
Two new type III effector classes added: XopAL and XopAM. These effectors are homologs of Eop3 and HopR1, respectively.
2009, August 31:
Dickeya dadantii Ech703 ("Dd") added to the type III effector table. No hit to any of the effectors.
2009, August 24:
New nomenclature of type III effectors released.
2009, July 31:
The Xanthomonas resource went online.
2009, July 15:
The Xanthomonas resource was introduced for the first time at the Xanthomonas Genomics Conference 2009.

-- Ralf Koebnik - 7 August 2012 --