Departamento de Biotecnología Microbiana y de Plantas, Centro de Investigaciones Biologicas-CSIC, Madrid, Spain.
Adv Exp Med Biol. 2018;1081:3-22. doi: 10.1007/978-981-13-1244-1_1.
Under low nonfreezing temperature conditions, plants from temperate climates undergo physiological and biochemical adjustments that increase their tolerance to freezing temperatures. This response, termed cold acclimation, is largely regulated by changes in gene expression. Molecular and genetic studies have identified a small family of transcription factors, called C-repeat binding factors (CBFs), as key regulators of the transcriptomic rearrangement that leads to cold acclimation. The function of these proteins is tightly controlled, and an inadequate supply of CBF activity may be detrimental to the plant. Accumulated evidence has revealed an extremely intricate network of positive and negative regulators of cold acclimation that coalesce at the level of CBF promoters constituting a central hub where multiple internal and external signals are integrated. Moreover, CBF expression is also controlled at posttranscriptional and posttranslational levels further refining CBF regulation. Recently, natural variation studies in Arabidopsis have demonstrated that mutations resulting in changes in CBF expression have an adaptive value for wild populations. Intriguingly, CBF genes are also present in plant species that do not cold acclimate, which suggest that they may also have additional functions. For instance, CBFs are required for some cold-related abiotic stress responses. In addition, their involvement in plant development deserves further study. Although more studies are necessary to fully harness CBF biotechnological potential, these transcription factors are meant to be key for a rational design of crops with enhanced tolerance to abiotic stress.
在低温非冻结条件下，来自温带气候的植物会经历生理和生化调整，以提高其对冷冻温度的耐受性。这种反应被称为低温驯化，主要受基因表达变化的调节。分子和遗传研究已经确定了一小类转录因子，称为 C 重复结合因子（CBF），作为导致低温驯化的转录组重排的关键调节因子。这些蛋白质的功能受到严格控制，CBF 活性供应不足可能对植物有害。越来越多的证据揭示了低温驯化的正调控和负调控之间极其复杂的网络，这些调控在 CBF 启动子水平上汇聚，形成一个中央枢纽，多个内部和外部信号在此处整合。此外，CBF 的表达也受到转录后和翻译后水平的调控，进一步细化了 CBF 的调控。最近，拟南芥的自然变异研究表明，导致 CBF 表达变化的突变对野生种群具有适应性价值。有趣的是，CBF 基因也存在于不进行低温驯化的植物物种中，这表明它们可能还有其他功能。例如，CBF 对于一些与冷相关的非生物胁迫反应是必需的。此外，它们在植物发育中的作用值得进一步研究。尽管还需要更多的研究来充分利用 CBF 的生物技术潜力，但这些转录因子有望成为设计具有增强抗非生物胁迫能力的作物的关键。
