title: Functional characterization of a sucrose:fructan 6-fructosyltransferase of the cold-resistant grass Bromus pictus by heterelogous expression in Pichia pastoris and Nicotiana tabacum and its involvement in freezing tolerance.
abstract: We have previously reported the molecular characterization of a putative sucrose:fructan 6-fructosyltransferase (6-SFT) of Bromus pictus, a graminean species from Patagonia, tolerant to cold and drought. Here, this enzyme was functionally characterized by heterologous expression in Pichia pastoris and Nicotiana tabacum. Recombinant P. pastoris Bp6-SFT showed comparable characteristics to barley 6-SFT and an evident fructosyltransferase activity synthesizing bifurcose from sucrose and 1-kestotriose. Transgenic tobacco plants expressing Bp6-SFT, showed fructosyltransferase activity and fructan accumulation in leaves. Bp6-SFT plants exposed to freezing conditions showed a significantly lower electrolyte leakage in leaves compared to control plants, indicating less membrane damage. Concomitantly these transgenic plants resumed growth more rapidly than control ones. These results indicate that Bp6-SFT transgenic tobacco plants that accumulate fructan showed enhanced freezing tolerance compared to control plants.
authors.affiliation: Instituto de Biotecnología, CICVyA, Instituto Nacional de Tecnología Agropecuaria (INTA Castelar) (1686), Hurlingham, Provincia de Buenos Aires, Argentina.
authors.forename: Florencia
authors.initials: F
authors.lastname: Del Viso
authors.forename: Adriana C
authors.initials: AC
authors.lastname: Casabuono
authors.forename: Alicia S
authors.initials: AS
authors.lastname: Couto
authors.forename: H Esteban
authors.initials: HE
authors.lastname: Hopp
authors.forename: Andrea F
authors.initials: AF
authors.lastname: Puebla
authors.forename: Ruth A
authors.initials: RA
authors.lastname: Heinz
mesh_terms: D000222:Adaptation, Physiological; D001483:Base Sequence; D031724:Bromus / Q000201:enzymology*; D002852:Chromatography, Ion Exchange; D017931:DNA Primers; D005615:Freezing; D006602:Hexosyltransferases / Q000378:metabolism*; D010843:Pichia / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014026:Nicotiana / Q000235:genetics*
chemical_list: D017931:DNA Primers; D006602:Hexosyltransferases; C097181:sucrose - fructan 6-fructosyltransferase