title: Change of function of the wheat stress-responsive transcriptional repressor TaRAP2.1L by repressor motif modification.
abstract: Plants respond to abiotic stresses by changes in gene regulation, including stress-inducible expression of transcriptional activators and repressors. One of the best characterized families of drought-related transcription factors are dehydration-responsive element binding (DREB) proteins, known as C-repeat binding factors (CBF). The wheat DREB/CBF gene TaRAP2.1L was isolated from drought-affected tissues using a dehydration-responsive element (DRE) as bait in a yeast one-hybrid screen. TaRAP2.1L is induced by elevated abscisic acid, drought and cold. A C-terminal ethylene responsive factor-associated amphiphilic repression (EAR) motif, known to be responsible for active repression of target genes, was identified in the TaRAP2.1L protein. It was found that TaRAP2.1L has a unique selectivity of DNA-binding, which differs from that of DREB activators. This binding selectivity remains unchanged in a TaRAP2.1L variant with an inactivated EAR motif (TaRAP2.1Lmut). To study the role of the TaRAP2.1L repressor activity associated with the EAR motif in planta, transgenic wheat overexpressing native or mutated TaRAP2.1L was generated. Overexpression of TaRAP2.1L under constitutive and stress-inducible promoters in transgenic wheat and barley led to dwarfism and decreased frost tolerance. By contrast, constitutive overexpression of the TaRAP2.1Lmut gene had little or no negative influence on wheat development or grain yield. Transgenic lines with the TaRAP2.1Lmut transgene had an enhanced ability to survive frost and drought. The improved stress tolerance is attributed to up-regulation of several stress-related genes known to be downstream genes of DREB/CBF activators.
authors.affiliation: Australian Centre for Plant Functional Genomics, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, SA, Australia.
authors.forename: Amritha
authors.initials: A
authors.lastname: Amalraj
authors.affiliation: Australian Centre for Plant Functional Genomics, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, SA, Australia.
authors.forename: Sukanya
authors.initials: S
authors.lastname: Luang
authors.affiliation: Australian Centre for Plant Functional Genomics, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, SA, Australia.
authors.forename: Manoj Yadav
authors.initials: MY
authors.lastname: Kumar
authors.affiliation: Australian Centre for Plant Functional Genomics, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, SA, Australia.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Sornaraj
authors.affiliation: Australian Centre for Plant Functional Genomics, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, SA, Australia.
authors.forename: Omid
authors.initials: O
authors.lastname: Eini
authors.affiliation: Australian Centre for Plant Functional Genomics, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, SA, Australia.
authors.forename: Nataliya
authors.initials: N
authors.lastname: Kovalchuk
authors.affiliation: Australian Centre for Plant Functional Genomics, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, SA, Australia.
authors.forename: Natalia
authors.initials: N
authors.lastname: Bazanova
authors.affiliation: Australian Centre for Plant Functional Genomics, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, SA, Australia.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Australian Centre for Plant Functional Genomics, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, SA, Australia.
authors.forename: Nannan
authors.initials: N
authors.lastname: Yang
authors.affiliation: Australian Centre for Plant Functional Genomics, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, SA, Australia.
authors.forename: Serik
authors.initials: S
authors.lastname: Eliby
authors.affiliation: Australian Centre for Plant Functional Genomics, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, SA, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Langridge
authors.affiliation: Australian Centre for Plant Functional Genomics, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, SA, Australia.
authors.forename: Maria
authors.initials: M
authors.lastname: Hrmova
authors.affiliation: Australian Centre for Plant Functional Genomics, School of Agriculture Food and Wine, University of Adelaide, Glen Osmond, SA, Australia.
authors.forename: Sergiy
authors.initials: S
authors.lastname: Lopato
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D000595:Amino Acid Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism; D005615:Freezing; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D001467:Hordeum / Q000235:genetics; D008958:Models, Molecular; D050505:Mutant Proteins / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D000072417:Protein Domains; D012097:Repressor Proteins / Q000378:metabolism*; D016415:Sequence Alignment; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects; D015533:Transcriptional Activation / Q000187:drug effects; D014908:Triticum / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D050505:Mutant Proteins; D010940:Plant Proteins; D012097:Repressor Proteins; D000040:Abscisic Acid
keywords: EAR motif; dehydration-responsive element binding proteins; drought; frost; transcriptional repressor; transgenic wheat