TheArabidopsis14-3-3 Protein RARE COLD INDUCIBLE 1A Links Low-Temperature Response and Ethylene Biosynthesis to Regulate Freezing Tolerance and Cold Acclimation  

Abstract

In plants, the expression of 14-3-3 genes reacts to various adverse environmental conditions, including cold, high salt, and drought. Although these results suggest that 14-3-3 proteins have the potential to regulate plant responses to abiotic stresses, their role in such responses remains poorly understood. Previously, we showed that the RARE COLD INDUCIBLE 1A (RCI1A) gene encodes the 14-3-3 psi isoform. Here, we present genetic and molecular evidence implicating RCI1A in the response to low temperature. Our results demonstrate that RCI1A functions as a negative regulator of constitutive freezing tolerance and cold acclimation in Arabidopsis thaliana by controlling cold-induced gene expression. Interestingly, this control is partially performed through an ethylene (ET)-dependent pathway involving physical interaction with different ACC SYNTHASE (ACS) isoforms and a decreased ACS stability. We show that, consequently, RCI1A restrains ET biosynthesis, contributing to establish adequate levels of this hormone in Arabidopsis under both standard and low-temperature conditions. We further show that these levels are required to promote proper cold-induced gene expression and freezing tolerance before and after cold acclimation. All these data indicate that RCI1A connects the low-temperature response with ET biosynthesis to modulate constitutive freezing tolerance and cold acclimation in Arabidopsis.

The LSM1-7 Complex Differentially Regulates Arabidopsis Tolerance to Abiotic Stress Conditions by Promoting Selective mRNA Decapping

“…Low-temperature treatment for gene expression and immunoblot analyses was performed by transferring plants growing in Petri dishes or on soil under control conditions to a growth chamber set to 4°C for different periods of time under long-day photoperiods with a photon flux of 40 mmol m 22 s 21 . For the rest of experiments, plants were always exposed to 4°C for 24 h. In all cases, water and salt stress treatments were accomplished by transferring plants growing in Petri dishes under standard conditions to plates containing GM medium supplemented with 55% PEG or 150 mM NaCl, respectively, for 10 h. For immunoblot analysis, water and salt stress treatments were also performed for 24 h. Tolerance to freezing temperatures was determined on 2-week-old plants grown on soil as described (Catalá et al, 2014). In vitro tolerance to water (25% PEG) and salt (150 mM NaCl) stresses was assayed on 7-d-old seedlings grown on GM medium as reported (Verslues et al, 2006).…”

“…Freezing tolerance was analyzed in nonacclimated and cold-acclimated (7 d, 4°C) lsm1a lsm1b mutants exposed for 6 h to different freezing temperatures (Catalá et al, 2014). Nonacclimated mutants presented a similar capacity to tolerate freezing as the wild type, the LT 50 (temperature that causes 50% lethality) values being in both cases around 24.5°C (Supplemental Figure 3A).…”

“…Total protein was extracted from 2-week-old Arabidopsis LSM1A PRO -LSM1A-GFP, LSM1B PRO -LSM1B-GFP, and wild-type plants grown under control or stress conditions as reported (Catalá et al, 2014). Monoclonal anti-GFP (ab290; GR158277-1; Abcam) was used as primary antibody and horseradish peroxidase-conjugated anti-rabbit as secondary antibody.…”

Cold stress affects H + -ATPase and phospholipase D activity in Arabidopsis

“…Recently the involvement of 14-3-3 proteins in the plant response to salinity has been clear demonstrated for two 14-3-3 Arabidopsis isoforms that have been reported to regulate the Salt Overly Sensitive pathway, known to control sodium homeostasis during salt stress (Zhou et al, 2014). Moreover, the Arabidopsis 14-3-3 psi isoform has been proposed to modulate constitutive freezing tolerance and cold acclimation connecting the low-temperature response with ethylene biosynthesis (Catal a et al, 2014).…”

14-3-3 λ protein interacts with ADF1 to regulate actin cytoskeleton dynamics in Arabidopsis

“…The expression of 14-3-3 psi is specific induced by low temperature [25,26]. 14-3-3 psi negatively regulates plant freezing tolerance by modulating cold-induced gene expression [27]. In animals, 14-3-3 proteins indirectly regulate actin cytoskeleton assembly and disassembly through interacting with phosphorylated cofilin/ADF [28].…”