Light regulates attachment, exopolysaccharide production, and nodulation in Rhizobium leguminosarum through a LOV-histidine kinase photoreceptor

• Autores: Bonomi, H.R.; Posadas, D.M.; Paris, G.; Del Carmen Carrica, M.; Frederickson, M.; Pietrasanta, L.I.; Bogomolni, R.A.; Zorreguieta, A.; Goldbaum, F.A.
• Año de publicación: 2012
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Proc. Natl. Acad. Sci. U. S. A. 2012;109(30):12135-12140
• Materia: bacterial polysaccharide; bacterial protein; exopolysaccharide; light oxygen and voltage histidine kinase; unclassified drug; adaptation; amino terminal sequence; article; bacterial gene; bacterium culture; biofilm; blue light; environmental factor; illumination; light; lov gene; nodulation; nonhuman; pea; plant root; priority journal; protein synthesis; real time polymerase chain reaction; reverse transcription polymerase chain reaction; Rhizobium leguminosarum; symbiosis; Amino Acid Sequence; Bacterial Adhesion; Base Sequence; Biofilms; Blotting, Western; Flagella; Gentian Violet; Light; Microscopy, Electron, Scanning; Molecular Sequence Data; Peas; Photoreceptors, Microbial; Plant Root Nodulation; Polysaccharides, Bacterial; Protein Kinases; Protein Structure, Tertiary; Real-Time Polymerase Chain Reaction; Rhizobium leguminosarum; Sequence Alignment; Sequence Analysis, DNA; Statistics, Nonparametric; Symbiosis; algae; Bacteria (microorganisms); Embryophyta; Fabaceae; Fungi; Pisum sativum; Rhizobium leguminosarum
• Institución: Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales

Rhizobium leguminosarum is a soil bacterium that infects root hairs and induces the formation of nitrogen-fixing nodules on leguminous plants. Light, oxygen, and voltage (LOV)-domain proteins are bluelight receptors found in higher plants and many algae, fungi, and bacteria. The genome of R. leguminosarum bv. viciae 3841, a peanodulating endosymbiont, encodes a sensor histidine kinase containing a LOV domain at the N-terminal end (R-LOV-HK). R-LOV-HK has a typical LOV domain absorption spectrum with broad bands in the blue and UV-A regions and shows a truncated photocycle. Here we show that the R-LOV-HK protein regulates attachment to an abiotic surface and production of flagellar proteins and exopolysaccharide in response to light. Also, illumination of bacterial cultures before inoculation of pea roots increases the number of nodules per plant and the number of intranodular bacteroids. The effects of light on nodulation are dependent on a functional lov gene. The results presented in this work suggest that light, sensed by R-LOV-HK, is an important environmental factor that controls adaptive responses and the symbiotic efficiency of R. leguminosarum.
Fil:Posadas, D.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Fil:Zorreguieta, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.