IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Role of a LOV protein in the virulence of Xanthomonas axonopodis pv. citri
Autor/es:
KRAISELBURD I, ; DAURELIO LD.; TALÓN M.; TADEO F. ; ORELLANO EG.
Lugar:
Mar del Plata
Reunión:
Congreso; VIII Congreso Argentino de Microbiologia General –SAMIGE; 2012
Institución organizadora:
SAMIGE Sociedad Argentina de Microbiología General
Resumen:
Light is a major environmental stimulus. In living organisms light perception is carried out through photosensory proteins that belong to different families based on the structure of their light-absorbing molecules. LOV (Light, Oxygen and Voltage) domains are blue-light sensory modules that were originally described in plant phototropins. Data obtained from bacterial genome sequences revealed the presence of multiple photosensory proteins, whose physiological role are a subject of interest worldwide. Xanthomonas axonopodis pv. citri (Xac) is a gram negative bacterium responsible for citrus canker, a severe disease that affects the Citrus genus. The Xac genome sequence includes a gene encoding a LOV protein that contains a N-terminal LOV domain associated to a C-terminal histidine kinase and a response regulator domain (hybrid HK-RR). In a previous work we demonstrated that Xac-LOV protein is a legitimate blue light photoreceptor, carrying the conserved photochemical properties of the LOV proteins described to date. Moreover we found that Xac-LOV protein is involved in the regulation of several physiological processes directly involved in the bacterial ability to colonize host plants. In this work, we evaluated the interaction between Xac and orange (Citrus sinensis) plants, both biochemically and by a transcriptomic analysis of host plants inoculated with Xac wild type and a mutant strain which lacks the Xac-LOV protein. First, we could observe that the in planta bacterial growth was similar for both strains until two weeks after inoculation. However, we observed important differences in the symptoms exhibit by the leaves inoculated with the different Xac strains, mainly regarding the development of necrotic zones in the infected tissues. This effect was also very dependent on the illuminating conditions of the treated plants. These results demonstrate that blue light and the Xac-LOV protein have an essential role in the virulence process, being involved in the control of the host tissue damage caused by the phytopathogen. Moreover, preliminary data obtained from the transcriptomic analysis of orange leaves inoculated with the different Xac strains, showed a differential expresion for several plant genes associated with important metabolic pathways. These results indicate that Xac-LOV protein could have a role in the modulation of the metabolism of the host plant upon bacterial infection.