Arabidopsis thaliana eIF4E1 and eIF(iso)4E Participate in Cold Response and Promote Translation of Some Stress-Related mRNAs.

Kenia Salazar-Díaz,Jesús H Jorge-Pérez,Brenda Nieto-Rivera,Tzvetanka D Dinkova,Mayra Aquino-Luna,Marlon A Pulido-Torres,Marina Gavilanes-Ruiz,Eloísa Hernández-Lucero

doi:10.3389/fpls.2021.698585

Kenia Salazar-Díaz, Jesús H Jorge-Pérez + Show 6 more

Open Access

https://doi.org/10.3389/fpls.2021.698585

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Abstract

Plant defense and adaptation to adverse environmental conditions rely on gene expression control, such as mRNA transcription, processing, stability, and translation. Sudden temperature changes are common in the era of global warming; thus, understanding plant acclimation responses at the molecular level becomes imperative. mRNA translation initiation regulation has a pivotal role in achieving the synthesis of the appropriate battery of proteins needed to cope with temperature stress. In this study, we analyzed the role of translation initiation factors belonging to the eIF4E family in Arabidopsis acclimation to cold temperatures and freezing tolerance. Using knockout (KO) and overexpressing mutants of AteIF4E1 or AteIF(iso)4E, we found that AteIF4E1 but not AteIF(iso)4E overexpressing lines displayed enhanced tolerance to freezing without previous acclimation at 4°C. However, KO mutant lines, eif(iso)4e-1 and eif4e1-KO, were more sensitive to the stress. Cold acclimation in wild-type plants was accompanied by increased levels of eIF4E1 and eIF(iso)4E transcript levels, polysomes (P) enrichment, and shifts of these factors from translationally non-active to active fractions. Transcripts, previously found as candidates for eIF(iso)4E or eIF4E1 selective translation, changed their distribution in both P and total RNA in the presence of cold. Some of these transcripts changed their polysomal distribution in the mutant and one eIF4E1 overexpressing line. According to this, we propose a role of eIF4E1 and eIF(iso)4E in cold acclimation and freezing tolerance by regulating the expression of stress-related genes.

Highlights

As sessile organisms, plants have developed a wide range of strategies to strengthen their endurance to a changing surrounding ambient [reviewed in: Haak et al (2017)]
We assayed a similar cold treatment on 15-day-old plantlets and estimated protein levels for both translation factors in whole plantlet tissues. Both factors showed significantly higher levels as proteins, reaching increases that were higher than two-fold at 24 h of cold exposure (Figure 1). eIF(iso)4E displayed an earlier accumulation response as compared to eIF4E1
Such behavior suggests that both, eIF4E1 and eIF(iso)4E, could function in the cold response of Arabidopsis, their expression regulation under these conditions might differ

Summary

Introduction

Plants have developed a wide range of strategies to strengthen their endurance to a changing surrounding ambient [reviewed in: Haak et al (2017)]. Some defense mechanisms rely on gene expression control, encompassing regulation of mRNA transcription, processing, stability, and translation. Cold stress is common to plants growing in a temperate climate. In their habitat, the freezing season follows previous exposure to cold non-freezing temperatures. The freezing season follows previous exposure to cold non-freezing temperatures This process is known as cold acclimation and allows freezing tolerance acquisition (Thomashow, 1999). A set of cold-regulated transcription factors orchestrate the production of mRNAs corresponding to proteins responsible for membrane stability, osmotic equilibrium maintenance, antioxidant mechanisms activation, and the cold signaling cascade itself (Chinnusamy et al, 2007; Novillo et al, 2007)

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