Salazar-Díaz Kenia, Aquino-Luna Mayra, Hernández-Lucero Eloísa, Nieto-Rivera Brenda, Pulido-Torres Marlon A, Jorge-Pérez Jesús H, Gavilanes-Ruiz Marina, Dinkova Tzvetanka D
Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Mexico City, Mexico.
Front Plant Sci. 2021 Sep 30;12:698585. doi: 10.3389/fpls.2021.698585. eCollection 2021.
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 or , 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, and , were more sensitive to the stress. Cold acclimation in wild-type plants was accompanied by increased levels of and 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.
植物对逆境环境条件的防御和适应依赖于基因表达调控，如mRNA转录、加工、稳定性和翻译。在全球变暖的时代，温度突然变化很常见；因此，在分子水平上了解植物的适应反应变得势在必行。mRNA翻译起始调控在合成应对温度胁迫所需的一系列合适蛋白质方面起着关键作用。在本研究中，我们分析了拟南芥中属于eIF4E家族的翻译起始因子在适应低温和耐冻性中的作用。使用 或 的敲除（KO）和过表达突变体，我们发现过表达AteIF4E1而不是AteIF(iso)4E的株系在没有预先在4°C驯化的情况下表现出增强的耐冻性。然而，KO突变体株系 和 对胁迫更敏感。野生型植物的冷驯化伴随着 和 转录水平的增加、多核糖体（P）富集以及这些因子从翻译非活性部分向活性部分的转移。以前被发现是eIF(iso)4E或eIF4E1选择性翻译候选物的转录本，在低温存在下其在P和总RNA中的分布发生了变化。其中一些转录本在突变体和一个eIF4E1过表达株系中改变了它们的多核糖体分布。据此，我们提出eIF4E1和eIF(iso)4E通过调节胁迫相关基因的表达在冷驯化和耐冻性中发挥作用。
