Visualization of novel virulence activities of the Xanthomonas type effectros AvrBs1, AvrBs3 and AvrBs4

Article

Visualization of novel virulence activities of the Xanthomonas type effectros AvrBs1, AvrBs3 and AvrBs4

Gurlebeck D.; Jahn S.; Gurlebeck N.; Szczesny R.; Szurek B.; Hahn S.; Hause G. and Bonas L.

Mol. Plant Pathol. 10(2), 175-188 (2009)

Abstract

Xanthomonas campestris
pv.
vesicatoria
secretes at least 20
effector proteins through the type III secretion system directly
into plant cells. In this study, we uncovered virulence activities
of the effector proteins AvrBs1, AvrBs3 and AvrBs4 using
Agrobacterium
-mediated transient expression of the corresponding
genes in
Nicotiana benthamiana
, followed by microscopic
analyses. We showed that, in addition to the nuclear-localized
AvrBs3, the effector AvrBs1, which localizes to the plant cell
cytoplasm, also induces a morphological change in mesophyll cells.
Comparative analyses revealed that
avrBs3
-expressing plant cells
contain highly active nuclei. Furthermore, plant cells expressing
avrBs3
or
avrBs1
show a decrease in the starch content in
chloroplasts and an increased number of vesicles, indicating an
enlargement of the central vacuole and the cell wall. Both AvrBs1
and AvrBs3 cause an increased ion efflux when expressed in
N. benthamiana
. By contrast, expression of the
avrBs3
homologue
avrBs4
leads to large catalase crystals in peroxisomes, suggesting
a possible virulence function of AvrBs4 in the suppression
of the plant defence responses. Taken together, our data show
that microscopic inspection can uncover subtle and novel virulence
activities of type III effector proteins.

BibTeX

@article{UTF415,
  author        = {Gurlebeck D. and Jahn S. and Gurlebeck N. and Szczesny R. and Szurek B. and Hahn S. and Hause G. and Bonas L.},
  title         = {{Visualization of novel virulence activities of the Xanthomonas type effectros AvrBs1, AvrBs3 and AvrBs4}},
  journal       = {Mol. Plant Pathol.},
  volume        = {10},
  number        = {2},
  pages         = {175-188},
  year          = {2009},
  doi           = {10.1111/J.1364-3703.2008.00519.X},
}