Role of CBFs as Integrators of Chloroplast Redox, Phytochrome and Plant Hormone Signaling during Cold Acclimation

Abstract

Cold acclimation of winter cereals and other winter hardy species is a prerequisite to increase subsequent freezing tolerance. Low temperatures upregulate the expression of C-repeat/dehydration-responsive element binding transcription factors (CBF/DREB1) which in turn induce the expression of COLD-REGULATED (COR) genes. We summarize evidence which indicates that the integration of these interactions is responsible for the dwarf phenotype and enhanced photosynthetic performance associated with cold-acclimated and CBF-overexpressing plants. Plants overexpressing CBFs but grown at warm temperatures mimic the cold-tolerant, dwarf, compact phenotype; increased photosynthetic performance; and biomass accumulation typically associated with cold-acclimated plants. In this review, we propose a model whereby the cold acclimation signal is perceived by plants through an integration of low temperature and changes in light intensity, as well as changes in light quality. Such integration leads to the activation of the CBF-regulon and subsequent upregulation of COR gene and GA 2-oxidase (GA2ox) expression which results in a dwarf phenotype coupled with increased freezing tolerance and enhanced photosynthetic performance. We conclude that, due to their photoautotrophic nature, plants do not rely on a single low temperature sensor, but integrate changes in light intensity, light quality, and membrane viscosity in order to establish the cold-acclimated state. CBFs appear to act as master regulators of these interconnecting sensing/signaling pathways.

A Zinc Finger Protein Regulates Flowering Time and Abiotic Stress Tolerance in Chrysanthemum by Modulating Gibberellin Biosynthesis

“…In Arabidopsis, endogenous GA 4 content of the shoot is negatively correlated with expression of CBF1/DREB1b, and elevated CBF expression reduces the accumulation of bioactive GAs through expression levels of GA2ox in cold-induced plants (Achard et al, 2008). CBFs are considered to function as integrators of phytochrome and GA signaling during cold acclimation, and such integration can lead to the activation of the CBF regulon and subsequent upregulation of COR gene and GA2ox expression, the latter resulting in a dwarf phenotype, coupled with increased freezing tolerance and enhanced photosynthetic performance (Kurepin et al, 2013).…”

The Hevea brasiliensis AP2/ERF superfamily: from ethylene signalling to latex harvesting and physiological disease response

“…In the classification of Sakuma (2002), the HbERF-III genes were included in the CBF/DREB1 subfamily. The CBF/DREB1 genes have been extensively characterized in plants linked to the cold stress (Kurepin et al, 2013;Rehman & Mahmood, 2015). In Hevea, a small number of Cold Binding Factor/Dehydration Responsive Element Binding 1 (CBF/DREB1) genes were identified (Duan et al, 2013).…”

Optimal Regulation of the Balance between Productivity and Overwintering of Perennial Grasses in a Warmer Climate

“…This is a possible explanation for the interaction between vernalization and photoperiod during de-acclimation in temperate grasses. Also, given that CBFs can inhibit leaf growth via GA and DELLA proteins [34], the regulatory effect of VRN1 on CBF expression may explain the effects of vernalization on leaf growth and photosynthetic activity observed by Stapleton and Jones [115], and also its interaction with photoperiod.…”

“…Insufficient light not only limits growth rates, but can also prevent proper acclimation to several types of winter stress [28][29][30][31][32][33]. Light factors during the cold acclimation period can affect the freezing tolerance of herbaceous overwintering plants in several ways [34,35]. Firstly, a certain irradiance combined with low temperature increases photosystem II (PSII) excitation pressure, which is a signal leading to the development of freezing resistance [36][37][38][39][40].…”

“…C-REPEAT BINDING FACTORs (CBFs) appear to be central in the coordinated regulation of leaf growth and freezing tolerance in response to low temperature [34,74] (Figure 3). CBF transcription factors upregulate whole sets of genes encoding proteins with direct functions in freezing resistance [82].…”