Components of the Arabidopsis C-repeat/dehydration-responsive element binding factor cold-response pathway are conserved in Brassica napus and other plant species.
Many plants increase in freezing tolerance in response to low, nonfreezing temperatures, a phenomenon known as cold acclimation. Cold acclimation in Arabidopsis involves rapid cold-induced expression of the C-repeat/dehydration-responsive element binding factor (CBF) transcriptional activators followed by expression of CBF-targeted genes that increase freezing tolerance. Here, we present evidence for a CBF cold-response pathway in Brassica napus. We show that B. napus encodes CBF-like genes and that transcripts for these genes accumulate rapidly in response to low temperature followed closely by expression of the cold-regulated Bn115 gene, an ortholog of the Arabidopsis CBF-targeted COR15a gene. Moreover, we show that constitutive overexpression of the Arabidopsis CBF genes in transgenic B. napus plants induces expression of orthologs of Arabidopsis CBF-targeted genes and increases the freezing tolerance of both nonacclimated and cold-acclimated plants. Transcripts encoding CBF-like proteins were also found to accumulate rapidly in response to low temperature in wheat (Triticum aestivum L. cv Norstar) and rye (Secale cereale L. cv Puma), which cold acclimate, as well as in tomato (Lycopersicon esculentum var. Bonny Best, Castle Mart, Micro-Tom, and D Huang), a freezing-sensitive plant that does not cold acclimate. An alignment of the CBF proteins from Arabidopsis, B. napus, wheat, rye, and tomato revealed the presence of conserved amino acid sequences, PKK/RPAGRxKFxETRHP and DSAWR, that bracket the AP2/EREBP DNA binding domains of the proteins and distinguish them from other members of the AP2/EREBP protein family. We conclude that components of the CBF cold-response pathway are highly conserved in flowering plants and not limited to those that cold acclimate.
Jaglo
K R
KR
Department of Crop and Soil Science, Michigan State University, East Lansing, MI 48824, USA.
Kleff
S
S
Amundsen
K L
KL
Zhang
X
X
Haake
V
V
Zhang
J Z
JZ
Deits
T
T
Thomashow
M F
MF
D000064:Acclimatization / Q000502:physiology; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins; D001937:Brassica / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005615:Freezing; D018506:Gene Expression Regulation, Plant; D006360:Heat-Shock Proteins / Q000378:metabolism; D018551:Solanum lycopersicum / Q000502:physiology; D008969:Molecular Sequence Data; D018515:Plant Leaves / Q000502:physiology; D010940:Plant Proteins / Q000378:metabolism*; D012434:Secale / Q000502:physiology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors; D014908:Triticum / Q000502:physiology
D029681:Arabidopsis Proteins; C104898:BN28 protein, Brassica napus; C104387:CBF1 protein, Arabidopsis; C118228:CBF2 protein, Arabidopsis; C116166:COR15 protein, Arabidopsis; D004268:DNA-Binding Proteins; C114578:DREB1A protein, Arabidopsis; D006360:Heat-Shock Proteins; D010940:Plant Proteins; D015534:Trans-Activators; D014157:Transcription Factors