30092047, PLoS One. 2018 Aug 9;13(8):e0201982. doi: 10.1371/journal.pone.0201982. eCollection 2018.

Characterization method

enzyme activity assay,qRT-PCR

Genomic accession number


Nucelotide position range







Xanthomonas euvesicatoria/456327

Degradation or Biosynthesis


Gene Name

Locus Tag

Protein ID

Gene Position

GenBank Contig Range

EC Number

- XCV2724 CAJ24403.1 0 - 2376 (-) AM039952.1:3088883-3091259 -
- XCV2725 CAJ24404.1 2520 - 5415 (-) AM039952.1:3091403-3094298 -
- XCV2726 CAJ24405.1 5873 - 7694 (-) AM039952.1:3094756-3096577 -
- XCV2727 CAJ24406.1 7164 - 8253 (-) AM039952.1:3096047-3097136 -
- XCV2728 CAJ24407.1 8560 - 10147 (-) AM039952.1:3097443-3099030 -
- XCV2729 CAJ24408.1 10143 - 14502 (-) AM039952.1:3099026-3103385 -
- XCV2730 CAJ24409.1 14901 - 17718 (-) AM039952.1:3103784-3106601 -
- XCV2731 CAJ24410.1 17844 - 18096 (-) AM039952.1:3106727-3106979 -
- XCV2732 CAJ24411.1 18198 - 19952 (-) AM039952.1:3107081-3108835 -

Cluster number


Gene name

Gene position

Gene type

Found by CGCFinder?

- 1 - 2376 (-) CAZyme: GH146 Yes
- 2521 - 5415 (-) TC: gnl|TC-DB|G0LBU8|1.B.14.6.11 Yes
- 5874 - 7694 (-) other Yes
- 7165 - 8253 (-) other Yes
- 8561 - 10147 (-) CAZyme: GH43|GH43_29 Yes
- 10144 - 14502 (-) CAZyme: GH121 Yes
- 14902 - 17718 (-) TC: gnl|TC-DB|G0LBU8|1.B.14.6.11 Yes
- 17845 - 18096 (-) CDS No
- 18199 - 19952 (-) CDS No




30092047, PLoS One. 2018 Aug 9;13(8):e0201982. doi: 10.1371/journal.pone.0201982. eCollection 2018.


Functional characterization of unique enzymes in Xanthomonas euvesicatoria related to degradation of arabinofurano-oligosaccharides on hydroxyproline-rich glycoproteins.


Nakamura M, Yasukawa Y, Furusawa A, Fuchiwaki T, Honda T, Okamura Y, Fujita K, Iwai H


In this study, we clarified the functions of three uncharacterized enzymes, XCV2724, XCV2728, and XCV2729, in Xanthomonas euvesicatoria, the causal agent of bacterial spot of tomato and pepper. The genes corresponding to the three enzymes are homologs of hypBA1, hypBA2, and hypAA from Bifidobacterium longum and are unique to Xanthomonas spp. among plant pathogenic bacteria. Functional characterization of the recombinant enzymes expressed using microbial systems revealed that they degrade the arabinofurano-oligosaccharides present on hydroxyproline (Hyp)-rich glycoproteins (HRGPs) such as extensin and solanaceous lectins in plant cell walls. These enzymes work coordinately to degrade the oligosaccharides. First, XeHypAA (XCV2728), belonging to the glycoside hydrolase (GH) 43 family, releases L-arabinose from L-arabinofuranose (Araf)-alpha1,3-Araf-ss1,2-Araf-ss1,2-Araf-ss-Hyp (Ara4-Hyp), cleaving its alpha1,3 bond; second, XeHypBA2 (XCV2729), belonging to the GH121 family, releases the disaccharide Araf-ss1,2-Araf from Araf-ss1,2-Araf-ss1,2-Araf-ss-Hyp (Ara3-Hyp); finally, XeHypBA1 (XCV2724), belonging to GH family 127, releases L-arabinose from Araf-ss-Hyp (Ara-Hyp). In summary, the main oligosaccharide structure of Ara4-Hyp on the HRGPs is degraded to Ara3-Hyp, then to Ara-Hyp, and finally to Ara monosaccharides by the action of these three enzymes. HRGPs containing oligosaccharide substrates have been reported to contribute to plant defense, and interestingly, the promoter region of the operon (xehypBA2 and xehypAA) contains the plant-inducible promoter box for binding the regulator protein HrpX involved in pathogenicity. We then analyzed the expression level of the operon gene in hrp-inducing medium and in plants and constructed gene-deletion mutants. However, although the operon was evidently upregulated by HrpX, three single-gene deletion mutants (DeltaxehypBA1, DeltaxehypBA2, DeltaxehypAA) and even a triple-gene deletion mutant (DeltaxehypBA1-BA2-AA) remained pathogenic, and had no effect on nonhost resistance, either, indicating that these three enzymes are not involved in either pathogenicity or nonhost resistance reactions. This is the first report of enzymes in plant pathogenic bacteria that catalyze the degradation of Hyp-linked-L-arabinofuranosides in plant cell walls.