DEAR1, a transcriptional repressor of DREB protein that mediates plant defense and freezing stress responses in Arabidopsis

Abstract

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.

Opposing control by transcription factors MYB61 and MYB3 Increases Freezing Tolerance by relieving C-repeat Binding Factor suppression

“…SIZ1 up-regulates the expression of CBF3 through sumoylation, stabilizes ICE1 , and affects the accumulation of salicylic acid and PAD4-mediated pathogen resistance signaling . DEAR1 represses the expression of DREB1 as well as PR gene expression and the accumulation of salicylic acid, thereby limiting the growth of the Pseudomonas syringae pathogen (Tsutsui et al, 2009). MtCBF4, therefore, may be another example of a TF mediating cross talk between biotic and abiotic stress signaling pathways.…”

Do ethylene response factorS9 and -14 repress PR gene expression in the interaction between Piriformospora indica and Arabidopsis?

“…ERF9 has a motif in its promoter region which can act as a target of DEAR1. 16 ERF9 expression is strongly reduced in DEAR1 overexpressor lines whereas PR-1, -2, -3 and -5 are constitutively upregulated. 16 Here, we present evidence that ERF9 might be a negative regulator of PR gene expression.…”

“…16 ERF9 expression is strongly reduced in DEAR1 overexpressor lines whereas PR-1, -2, -3 and -5 are constitutively upregulated. 16 Here, we present evidence that ERF9 might be a negative regulator of PR gene expression. Since the ERF14 and ERF9 mRNA levels are upregulated in P. indica-colonized Arabidopsis roots, both members of the subgroup B were further investigated in this study.…”

“…This motif binds DREB transcriptional regulators, 23 one of them is DEAR1. Tsutsui et al 16 have shown that overexpression of DEAR1 leads to a repression of ERF9 expression. On the other hand PR genes and PDF1.2 are constitutive upregulated in the DEAR1 overexpressor line, which also accumulates endogenous salicylic acid (SA).…”

“…Tsutsui et al 16 showed in 2009 that DEAR1 (a member of the A family) plays a regulatory role in both freezing tolerance and response to pathogen infection. The authors concluded that DEAR1 mediates the crosstalk between abiotic and biotic stress signalling pathways in plants.…”