title: Identification of a Halotolerant Mutant via In Vitro Mutagenesis in the Cyanobacterium Fremyella diplosiphon.
abstract: Energy metabolism and photosynthetic pigment accumulation are affected by salt stress in cyanobacteria leading to cessation of growth. In this study, the effect of salinity on the freshwater cyanobacterium, Fremyella diplosiphon, was investigated and mutagenesis-based efforts were undertaken to enhance salt tolerance. Salinity at a concentration of 10 g/L sodium chloride (NaCl) inhibited growth of wild type F. diplosiphon under white, red, and green light. Efforts to enhance halotolerance resulted in a mutant that could survive in 20 g/L NaCl for 15 generations with no significant reduction in phycobiliproteins (phycocyanin, phycoerythrin, and allophycocyanin) or chlorophyll a. Gene expression measured by quantitative reverse transcription-polymerase chain reaction revealed a three-fold increase in tripartite ATP-independent periplasmic transporters (TRAP) solute receptor transcript in the mutant compared to wild type. Our discovery of a TRAP transporter system in F. diplosiphon and its possible role in salinity response enables growth in brackish waters, which enhances its potential for biotechnological applications.
authors.affiliation: Department of Biology, Morgan State University, Baltimore, MD, 21251, USA.
authors.forename: Behnam
authors.initials: B
authors.lastname: Tabatabai
authors.affiliation: Department of Pathology, Methodist Hospital Research Institute, Houston, TX, 77010, USA.
authors.forename: AnithaChristy S
authors.initials: AS
authors.lastname: Arumanayagam
authors.affiliation: Department of Biology, Morgan State University, Baltimore, MD, 21251, USA.
authors.forename: Oluwatomisin
authors.initials: O
authors.lastname: Enitan
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Sciences, University of Texas Health Science Centre, Houston, TX, 77030, USA.
authors.forename: Arunmani
authors.initials: A
authors.lastname: Mani
authors.affiliation: USDA-ARS, Soybean Genomics and Improvement Laboratory, Beltsville, MD, 20705, USA.
authors.forename: Savithiry S
authors.initials: SS
authors.lastname: Natarajan
authors.affiliation: Department of Biology, Morgan State University, Baltimore, MD, 21251, USA. viji.sitther@morgan.edu.
authors.forename: Viji
authors.initials: V
authors.lastname: Sitther
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D000458:Cyanobacteria / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism* / Q000528:radiation effects; D008027:Light; D016296:Mutagenesis; D009154:Mutation; D010788:Photosynthesis / Q000528:radiation effects; D012965:Sodium Chloride / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D002734:Chlorophyll; D012965:Sodium Chloride; D000077194:Chlorophyll A