title: Optimization of TaDREB3 gene expression in transgenic barley using cold-inducible promoters.
abstract: Constitutive over-expression of the TaDREB3 gene in barley improved frost tolerance of transgenic plants at the vegetative stage of plant development, but leads to stunted phenotypes and 3- to 6-week delays in flowering compared to control plants. In this work, two cold-inducible promoters with contrasting properties, the WRKY71 gene promoter from rice and the Cor39 gene promoter from durum wheat, were applied to optimize expression of TaDREB3. The aim of the work was to increase plant frost tolerance and to decrease or prevent negative developmental phenotypes observed during constitutive expression of TaDREB3. The OsWRKY71 and TdCor39 promoters had low-to-moderate basal activity and were activated by cold treatment in leaves, stems and developing spikes of transgenic barley and rice. Expression of the TaDREB3 gene, driven by either of the tested promoters, led to a significant improvement in frost tolerance. The presence of the functional TaDREB3 protein in transgenic plants was confirmed by the detection of strong up-regulation of cold-responsive target genes. The OsWRKY71 promoter-driven TaDREB3 provides stronger activation of the same target genes than the TdCor39 promoter. Analysis of the development of transgenic plants in the absence of stress revealed small or no differences in plant characteristics and grain yield compared with wild-type plants. The WRKY71-TaDREB3 promoter-transgene combination appears to be a promising tool for the enhancement of cold and frost tolerance in crop plants but field evaluation will be needed to confirm that negative development phenotypes have been controlled.
authors.affiliation: Australian Centre for Plant Functional Genomics, University of Adelaide, Adelaide, SA, Australia.
authors.forename: Nataliya
authors.initials: N
authors.lastname: Kovalchuk
authors.forename: Wei
authors.initials: W
authors.lastname: Jia
authors.forename: Omid
authors.initials: O
authors.lastname: Eini
authors.forename: Sarah
authors.initials: S
authors.lastname: Morran
authors.forename: Tatiana
authors.initials: T
authors.lastname: Pyvovarenko
authors.forename: Stephen
authors.initials: S
authors.lastname: Fletcher
authors.forename: Natalia
authors.initials: N
authors.lastname: Bazanova
authors.forename: John
authors.initials: J
authors.lastname: Harris
authors.forename: Kontanze
authors.initials: K
authors.lastname: Beck-Oldach
authors.forename: Yuri
authors.initials: Y
authors.lastname: Shavrukov
authors.forename: Peter
authors.initials: P
authors.lastname: Langridge
authors.forename: Sergiy
authors.initials: S
authors.lastname: Lopato
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D003001:Cloning, Molecular; D003080:Cold Temperature; D003433:Crosses, Genetic; D035264:Flowers / Q000502:physiology; D018628:Gene Dosage; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D006720:Homozygote; D001467:Hordeum / Q000235:genetics* / Q000254:growth & development; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D019076:Transgenes / Q000235:genetics; D014908:Triticum / Q000235:genetics*
chemical_list: D010940:Plant Proteins
keywords: DREB/CBF transcription factor; barley; cold/frost tolerance; plant development; rice; stress-inducible promoters