title: A novel gene SbSI-2 encoding nuclear protein from a halophyte confers abiotic stress tolerance in E. coli and tobacco.
abstract: Salicornia brachiata is an extreme halophyte that grows luxuriantly in coastal marshes. Previously, we have reported isolation and characterization of ESTs from Salicornia with large number of novel/unknown salt-responsive gene sequences. In this study, we have selected a novel salt-inducible gene SbSI-2 (Salicornia brachiata salt-inducible-2) for functional characterization. Bioinformatics analysis revealed that SbSI-2 protein has predicted nuclear localization signals and a strong protein-protein interaction domain. Transient expression of the RFP:SbSI2 fusion protein confirmed that SbSI-2 is a nuclear-localized protein. Genomic organization study showed that SbSI-2 is intronless and has a single copy in Salicornia genome. Quantitative RT-PCR analysis revealed higher SbSI-2 expression under salt stress and desiccation conditions. The SbSI-2 gene was transformed in E. coli and tobacco for functional characterization. pET28a-SbSI-2 recombinant E. coli cells showed higher tolerance to desiccation and salinity compared to vector alone. Transgenic tobacco plants overexpressing SbSI-2 have improved salt- and osmotic tolerance, accompanied by better growth parameters, higher relative water content, elevated accumulation of compatible osmolytes, lower Na+ and ROS accumulation and lesser electrolyte leakage than the wild-type. Overexpression of the SbSI-2 also enhanced transcript levels of ROS-scavenging genes and some stress-related transcription factors under salt and osmotic stresses. Taken together, these results demonstrate that SbSI-2 might play an important positive modulation role in abiotic stress tolerance. This identifies SbSI-2 as a novel determinant of salt/osmotic tolerance and suggests that it could be a potential bioresource for engineering abiotic stress tolerance in crop plants.
authors.affiliation: Discipline of Marine Biotechnology and Ecology, CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat, India.
authors.forename: Narendra Singh
authors.initials: NS
authors.lastname: Yadav
authors.affiliation: Discipline of Marine Biotechnology and Ecology, CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat, India.
authors.forename: Vijay Kumar
authors.initials: VK
authors.lastname: Singh
authors.affiliation: Discipline of Marine Biotechnology and Ecology, CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat, India.
authors.forename: Dinkar
authors.initials: D
authors.lastname: Singh
authors.affiliation: Discipline of Marine Biotechnology and Ecology, CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat, India; Academy of Scientific and Innovative Research, CSIR, New Delhi, India.
authors.forename: Bhavanath
authors.initials: B
authors.lastname: Jha
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D019663:Chenopodiaceae / Q000235:genetics; D002734:Chlorophyll / Q000378:metabolism; D004926:Escherichia coli / Q000166:cytology / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D018628:Gene Dosage; D023281:Genomics; D009687:Nuclear Proteins / Q000235:genetics; D009997:Osmotic Pressure / Q000187:drug effects; D010940:Plant Proteins / Q000235:genetics*; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D054712:Salinity; D055051:Salt-Tolerant Plants / Q000235:genetics*; D012492:Salts / Q000494:pharmacology; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics*; D014026:Nicotiana / Q000166:cytology / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D009687:Nuclear Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D012492:Salts; D014157:Transcription Factors; D002734:Chlorophyll