Jahed Khalil R, Saini Amolpreet Kaur, Sherif Sherif M
Alson H. Smith Jr. Agricultural Research and Extension Center, School of Plant and Environmental Sciences, Virginia Tech, Winchester, VA, United States.
Front Plant Sci. 2023 Aug 15;14:1246093. doi: 10.3389/fpls.2023.1246093. eCollection 2023.
Low temperature stress significantly threatens crop productivity and economic sustainability. Plants counter this by deploying advanced molecular mechanisms to perceive and respond to cold stress. Transmembrane proteins initiate these responses, triggering a series of events involving secondary messengers such as calcium ions (Ca), reactive oxygen species (ROS), and inositol phosphates. Of these, calcium signaling is paramount, activating downstream phosphorylation cascades and the transcription of cold-responsive genes, including cold-regulated (COR) genes. This review focuses on how plants manage freeze-induced damage through dual strategies: cold tolerance and cold avoidance. Tolerance mechanisms involve acclimatization to decreasing temperatures, fostering gradual accumulation of cold resistance. In contrast, avoidance mechanisms rely on cryoprotectant molecules like potassium ions (K), proline, glycerol, and antifreeze proteins (AFPs). Cryoprotectants modulate intracellular solute concentration, lower the freezing point, inhibit ice formation, and preserve plasma membrane fluidity. Additionally, these molecules demonstrate antioxidant activity, scavenging ROS, preventing protein denaturation, and subsequently mitigating cellular damage. By forming extensive hydrogen bonds with water molecules, cryoprotectants also limit intercellular water movement, minimizing extracellular ice crystal formation, and cell dehydration. The deployment of cryoprotectants is a key adaptive strategy that bolsters plant resilience to cold stress and promotes survival in freezing environments. However, the specific physiological and molecular mechanisms underlying these protective effects remain insufficiently understood. Therefore, this review underscores the need for further research to elucidate these mechanisms and assess their potential impact on crop productivity and sustainability, contributing to the progressive discourse in plant biology and environmental science.
低温胁迫严重威胁作物生产力和经济可持续性。植物通过部署先进的分子机制来感知和应对冷胁迫，以此来应对这一问题。跨膜蛋白启动这些反应，触发一系列涉及钙离子（Ca）、活性氧（ROS）和肌醇磷酸等二级信使的事件。其中，钙信号传导至关重要，它能激活下游磷酸化级联反应以及包括冷调节（COR）基因在内的冷响应基因的转录。本综述重点关注植物如何通过耐寒和避寒这两种策略来应对冻害。耐受机制包括适应温度降低，促进抗寒能力的逐渐积累。相比之下，避寒机制依赖于钾离子（K）、脯氨酸、甘油和抗冻蛋白（AFP）等抗冻剂分子。抗冻剂调节细胞内溶质浓度，降低冰点，抑制冰的形成，并保持质膜流动性。此外，这些分子还具有抗氧化活性，清除活性氧，防止蛋白质变性，从而减轻细胞损伤。通过与水分子形成广泛的氢键，抗冻剂还限制细胞间水分移动，最大限度地减少细胞外冰晶形成和细胞脱水。抗冻剂的部署是一种关键的适应性策略，可增强植物对冷胁迫的恢复力，并促进其在冰冻环境中的存活。然而，这些保护作用背后的具体生理和分子机制仍未得到充分理解。因此，本综述强调需要进一步研究以阐明这些机制，并评估它们对作物生产力和可持续性的潜在影响，为植物生物学和环境科学的进展性讨论做出贡献。
