Differential regulation of transcript accumulation and alternative splicing of a DREB2 homolog under abiotic stress conditions in common wheat.
A number of cold responsive (Cor)/late embryogenesis abundant (Lea) genes are induced by both low temperature (LT) and dehydration. To understand the molecular basis of cold acclimation and its relationship with drought stress response in wheat seedlings, we isolated a DREB2 homolog Wdreb2, which is the candidate gene for a transcription factor of the Cor/Lea genes. The Wdreb2 expression was activated by cold, drought, salt and exogenous ABA treatment. Detailed expression studies of Wdreb2 indicated the involvement of two distinct pathways of its activation, a drought and salt stress-responsive pathway and a cold-responsive pathway. The transient expression analysis showed that the Wrab19 expression was directly activated by the WDREB2 transcription factor in wheat cells. Three transcript forms of Wdreb2 (Wdreb2alpha, Wdreb2beta and Wdreb2gamma) were produced through alternative splicing. Under drought and salt stress conditions, the amount of the Wdreb2beta form remained fairly constant during 24-hour treatment, while those of the Wdreb2alpha and Wdreb2gamma forms showed transient increases. On the other hand, the LT treatment resulted in increased transcript levels of all three forms of Wdreb2. Thus, under the LT and drought/salt stress conditions the amount of the WDREB2 transcription factors in wheat is differentially controlled by the level of transcription and alternative splicing.
Egawa
Chikako
C
Laboratory of Plant Genetics, Department of Biological and Environmental Science, Faculty of Agriculture, and Graduate School of Science and Technology, Kobe University.
Kobayashi
Fuminori
F
Ishibashi
Machiko
M
Nakamura
Toshiki
T
Nakamura
Chiharu
C
Takumi
Shigeo
S
D000040:Abscisic Acid / Q000494:pharmacology; D000064:Acclimatization; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000378:metabolism; D003080:Cold Temperature / Q000009:adverse effects; D003681:Dehydration / Q000378:metabolism; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D012275:Oryza / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D014908:Triticum / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; C114579:DREB2A protein, Arabidopsis; D010940:Plant Proteins; D014157:Transcription Factors; C066246:late embryogenesis abundant protein, plant; D000040:Abscisic Acid