DEAR1, a transcriptional repressor of DREB protein that mediates plant defense and freezing stress responses in Arabidopsis.
Plants have evolved intricate mechanisms to respond and adapt to a wide variety of biotic and abiotic stresses in their environment. The Arabidopsis DEAR1 (DREB and EAR motif protein 1; At3g50260) gene encodes a protein containing significant homology to the DREB1/CBF (dehydration-responsive element binding protein 1/C-repeat binding factor) domain and the EAR (ethylene response factor-associated amphiphilic repression) motif. We show here that DEAR1 mRNA accumulates in response to both pathogen infection and cold treatment. Transgenic Arabidopsis overexpressing DEAR1 (DEAR1ox) showed a dwarf phenotype and lesion-like cell death, together with constitutive expression of PR genes and accumulation of salicylic acid. DEAR1ox also showed more limited P. syringae pathogen growth compared to wild-type, consistent with an activated defense phenotype. In addition, transient expression experiments revealed that the DEAR1 protein represses DRE/CRT (dehydration-responsive element/C-repeat)-dependent transcription, which is regulated by low temperature. Furthermore, the induction of DREB1/CBF family genes by cold treatment was suppressed in DEAR1ox, leading to a reduction in freezing tolerance. These results suggest that DEAR1 has an upstream regulatory role in mediating crosstalk between signaling pathways for biotic and abiotic stress responses.
Tsutsui
Tomokazu
T
Faculty of Advanced Life Science, Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo, 060-0810, Japan. ttsutsui@sci.hokudai.ac.jp
Kato
Wataru
W
Asada
Yutaka
Y
Sako
Kaori
K
Sato
Takeo
T
Sonoda
Yutaka
Y
Kidokoro
Satoshi
S
Yamaguchi-Shinozaki
Kazuko
K
Tamaoki
Masanori
M
Arakawa
Keita
K
Ichikawa
Takanari
T
Nakazawa
Miki
M
Seki
Motoaki
M
Shinozaki
Kazuo
K
Matsui
Minami
M
Ikeda
Akira
A
Yamaguchi
Junji
J
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D005615:Freezing; D020869:Gene Expression Profiling; D008969:Molecular Sequence Data; D012097:Repressor Proteins / Q000737:chemistry / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic / Q000502:physiology*
D029681:Arabidopsis Proteins; C114578:DREB1A protein, Arabidopsis; D012097:Repressor Proteins; D014157:Transcription Factors