title: Water soluble exo-polysaccharide from Syncephalastrum racemosum, a strong inducer of plant defence reactions.
abstract: This study examines the production, characterization and bioactivity on plant cell cultured in vitro of exopolysaccharides (EPS) from Syncephalastrum racemosum CBS 443.59. Firstly, the influence of the fungus culture condition in shake flasks (pH, temperature and different carbon and nitrogen sources) on EPS and biomass production was evaluated. In order to enhance EPS production, a new protocol based on two-stage pH fermentation in a 3 L stirred fermentor was developed. Under this condition, EPS production increased by 3.55 times, compared to a constant pH process, reaching a maximal EPS concentration of 2.62 g/L. Structurally, the EPS contains a polyglucuronic acid backbone, linked essentially with mannose and fucose units and some galactose and glucose units. The bioactivity of EPS as inducer of defence reactions in plant suspension-cultured cells was also studied. Our results show, for first time, that EPS from S. racemosum CBS 443.59 induces, depending on the concentration, PAL activation and H2O2 synthesis in Arabidopsis thaliana cell suspensions.
authors.affiliation: University of Liège, Gembloux Agro-Bio Tech, Chimie Biologique Industrielle, 2 Passage des Déportés, 5030 Gembloux, Belgium. Electronic address: manu.valepyn@hotmail.com.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Valepyn
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Cabrera
authors.forename: Aurore
authors.initials: A
authors.lastname: Richel
authors.forename: Michel
authors.initials: M
authors.lastname: Paquot
mesh_terms: D002478:Cells, Cultured; D005285:Fermentation; D062610:Fungal Polysaccharides / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D009005:Monosaccharides / Q000032:analysis; D009090:Mucorales / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D062610:Fungal Polysaccharides; D009005:Monosaccharides; D014867:Water
keywords: Bioactivity; Culture conditions; Exopolysaccharide; Syncephalastrum racemosum