title: Far-red light photoacclimation (FaRLiP) in Synechococcus sp. PCC 7335: I. Regulation of FaRLiP gene expression.
abstract: Far-red light photoacclimation (FaRLiP) is a mechanism that allows some cyanobacteria to utilize far-red light (FRL) for oxygenic photosynthesis. During FaRLiP, cyanobacteria remodel photosystem (PS) I, PS II, and phycobilisomes while synthesizing Chl d, Chl f, and far-red-absorbing phycobiliproteins, and these changes enable these organisms to use FRL for growth. In this study, a conjugation-based genetic system was developed for Synechococcus sp. PCC 7335. Three antibiotic cassettes were successfully used to generate knockout mutations in genes in Synechococcus sp. PCC 7335, which should allow up to three gene loci to be modified in one strain. This system was used to delete the rfpA, rfpB, and rfpC genes individually, and characterization of the mutants demonstrated that these genes control the expression of the FaRLiP gene cluster in Synechococcus sp. PCC 7335. The mutant strains exhibited some surprising differences from similar mutants in other FaRLiP strains. Notably, mutations in any of the three master transcription regulatory genes led to enhanced synthesis of phycocyanin and PS II. A time-course study showed that acclimation of the photosynthetic apparatus from that produced in white light to that produced in FRL occurs very slowly over a period 12-14 days in this strain and that it is associated with a substantial reduction (~34 %) in the chlorophyll a content of the cells. This study shows that there are differences in the detailed responses of cyanobacteria to growth in FRL in spite of the obvious similarities in the organization and regulation of the FaRLiP gene cluster.
authors.affiliation: 403C Althouse Laboratory, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA.|Intercollege Graduate Degree Program in Plant Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
authors.forename: Ming-Yang
authors.initials: MY
authors.lastname: Ho
authors.affiliation: 403C Althouse Laboratory, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
authors.forename: Fei
authors.initials: F
authors.lastname: Gan
authors.affiliation: 403C Althouse Laboratory, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
authors.forename: Gaozhong
authors.initials: G
authors.lastname: Shen
authors.affiliation: 403C Althouse Laboratory, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
authors.forename: Chi
authors.initials: C
authors.lastname: Zhao
authors.affiliation: 403C Althouse Laboratory, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA. dab14@psu.edu.|Intercollege Graduate Degree Program in Plant Biology, The Pennsylvania State University, University Park, PA, 16802, USA. dab14@psu.edu.|Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA. dab14@psu.edu.
authors.forename: Donald A
authors.identifier: http://orcid.org/0000-0003-2782-5988
authors.initials: DA
authors.lastname: Bryant
mesh_terms: D000222:Adaptation, Physiological; D001426:Bacterial Proteins / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008027:Light; D009154:Mutation; D013050:Spectrometry, Fluorescence; D046940:Synechococcus / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins
keywords: Chlorophyll f; Cyanobacteria; Far-red light; Photoacclimation; Photosynthesis