title: Bacteriophytochrome controls carotenoid-independent response to photodynamic stress in a non-photosynthetic rhizobacterium, Azospirillum brasilense Sp7.
abstract: Ever since the discovery of the role of bacteriophytochrome (BphP) in inducing carotenoid synthesis in Deinococcus radiodurans in response to light the role of BphPs in other non-photosynthetic bacteria is not clear yet. Azospirillum brasilense, a non-photosynthetic rhizobacterium, harbours a pair of BphPs out of which AbBphP1 is a homolog of AtBphP1 of Agrobacterium tumefaciens. By overexpression, purification, biochemical and spectral characterization we have shown that AbBphP1 is a photochromic bacteriophytochrome. Phenotypic study of the ΔAbBphP1 mutant showed that it is required for the survival of A. brasilense on minimal medium under red light. The mutant also showed reduced chemotaxis towards dicarboxylates and increased sensitivity to the photooxidative stress. Unlike D. radiodurans, AbBphP1 was not involved in controlling carotenoid synthesis. Proteome analysis of the ΔAbBphP1 indicated that AbBphP1 is involved in inducing a cellular response that enables A. brasilense in regenerating proteins that might be damaged due to photodynamic stress.
authors.affiliation: School of Biotechnology, Faculty of Science, Banaras Hindu University , Varanasi-221005, India.
authors.forename: Santosh
authors.initials: S
authors.lastname: Kumar
authors.forename: Suneel
authors.initials: S
authors.lastname: Kateriya
authors.forename: Vijay Shankar
authors.initials: VS
authors.lastname: Singh
authors.forename: Meenakshi
authors.initials: M
authors.lastname: Tanwar
authors.forename: Shweta
authors.initials: S
authors.lastname: Agarwal
authors.forename: Hina
authors.initials: H
authors.lastname: Singh
authors.forename: Jitendra Paul
authors.initials: JP
authors.lastname: Khurana
authors.forename: Devinder Vijay
authors.initials: DV
authors.lastname: Amla
authors.forename: Anil Kumar
authors.initials: AK
authors.lastname: Tripathi
mesh_terms: D015806:Azospirillum brasilense / Q000254:growth & development / Q000378:metabolism*; D001426:Bacterial Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D002338:Carotenoids / Q000378:metabolism*; D019281:Dimerization; D008027:Light; D009154:Mutation; D010802:Phylogeny; D010834:Phytochrome / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D014048:Tolonium Chloride / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D010834:Phytochrome; D014048:Tolonium Chloride; D002338:Carotenoids