title: Improvement of stress tolerance of wheat and barley by modulation of expression of DREB/CBF factors.
abstract: Transcription factors have been shown to control the activity of multiple stress response genes in a coordinated manner and therefore represent attractive targets for application in molecular plant breeding. We investigated the possibility of modulating the transcriptional regulation of drought and cold responses in the agriculturally important species, wheat and barley, with a view to increase drought and frost tolerance. Transgenic wheat and barley plants were generated showing constitutive (double 35S) and drought-inducible (maize Rab17) expression of the TaDREB2 and TaDREB3 transcription factors isolated from wheat grain. Transgenic populations with constitutive over-expression showed slower growth, delayed flowering and lower grain yields relative to the nontransgenic controls. However, both the TaDREB2 and TaDREB3 transgenic plants showed improved survival under severe drought conditions relative to nontransgenic controls. There were two components to the drought tolerance: real (activation of drought-stress-inducible genes) and 'seeming' (consumption of less water as a result of smaller size and/or slower growth of transgenics compared to controls). The undesired changes in plant development associated with the 'seeming' component of tolerance could be alleviated by using a drought-inducible promoter. In addition to drought tolerance, both TaDREB2 and TaDREB3 transgenic plants with constitutive over-expression of the transgene showed a significant improvement in frost tolerance. The increased expression of TaDREB2 and TaDREB3 lead to elevated expression in the transgenics of 10 other CBF/DREB genes and a large number of stress responsive LEA/COR/DHN genes known to be responsible for the protection of cell from damage and desiccation under stress.
authors.affiliation: Australian Centre for Plant Functional Genomics, University of Adelaide, Urrbrae, Adelaide, SA, Australia.
authors.forename: Sarah
authors.initials: S
authors.lastname: Morran
authors.forename: Omid
authors.initials: O
authors.lastname: Eini
authors.forename: Tatiana
authors.initials: T
authors.lastname: Pyvovarenko
authors.forename: Boris
authors.initials: B
authors.lastname: Parent
authors.forename: Rohan
authors.initials: R
authors.lastname: Singh
authors.forename: Ainur
authors.initials: A
authors.lastname: Ismagul
authors.forename: Serik
authors.initials: S
authors.lastname: Eliby
authors.forename: Neil
authors.initials: N
authors.lastname: Shirley
authors.forename: Peter
authors.initials: P
authors.lastname: Langridge
authors.forename: Sergiy
authors.initials: S
authors.lastname: Lopato
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics; D003080:Cold Temperature; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D005818:Genetic Engineering; D001467:Hordeum / Q000235:genetics* / Q000502:physiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D030821:Plants, Genetically Modified / Q000378:metabolism; D011401:Promoter Regions, Genetic; D013312:Stress, Physiological / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D014908:Triticum / Q000235:genetics* / Q000502:physiology
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors; C071710:DHN1 protein, Zea mays