INVESTIGADORES
VOJNOV Adrian Alberto
artículos
Título:
Xanthomonas campestris attenuates virulence by sensing light through a bacteriophytochrome photoreceptor
Autor/es:
BONOMI HR; TOUM L; SYCZ G; SIEIRA R; TOSCANI A; GUDESBLAT GE; LESKOW F; GOLDBAUM FA; VOJNOV, ADRIAN ALBERTO; MALAMUD FLORENCIA
Revista:
EMBO REPORTS
Editorial:
NATURE PUBLISHING GROUP
Referencias:
Lugar: Londres; Año: 2016
ISSN:
1469-221X
Resumen:
Phytochromes constitute a major photoreceptor family found in plants, algae, fungi, and30 prokaryotes, including pathogens. Here we report that Xanthomonas campestris pv. campestris31 (Xcc), the causal agent of black rot disease which affects cruciferous crops worldwide, codes for a32 functional bacteriophytochrome (XccBphP). XccBphP possesses an N-terminal PAS2-GAF-PHY33 photosensory domain triad and a C-terminal PAS9 domain as its output module. Our findings show34 that illumination of Xcc, prior to plant infection, attenuates its virulence in an XccBphP-dependent35 manner. Moreover, in response to light, XccBphP down-regulates xanthan exopolysaccharide36 production and biofilm formation, two known Xcc virulence factors. Furthermore, the XccbphP37 null-mutant shows enhanced virulence, similar to that of dark-adapted Xcc cultures. Stomatal38 aperture regulation and callose deposition, both well-established plant defense mechanisms against39 bacterial pathogens, are overridden by the XccbphP strain. Additionally, an RNA-Seq analysis40 reveals that far-red light or XccBphP overexpression produce genome-wide transcriptional changes,41 including the inhibition of several Xcc virulence systems. Our findings show that Xcc senses light42 through XccBphP, eliciting bacterial virulence attenuation via down-regulation of bacterial43 virulence factors. The capacity of XccBphP to respond to light both in vitro and in vivo was44 abolished by a mutation on the conserved Cys13 residue. These results provide evidence for a novel45 bacteriophytochrome function affecting an infectious process.