State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, Zhejiang, China.
College of Life Sciences, Zhejiang University, Hangzhou, 310058, Zhejiang, China.
BMC Plant Biol. 2022 Mar 14;22(1):114. doi: 10.1186/s12870-022-03507-x.
Red algae Porphyra sensu lato grow naturally in the unfavorable intertidal environment, in which they are exposed to substantial temperature fluctuations. The strategies of Porphyra to tolerate cold stress are poorly understood.
Herein, investigations revealed that chilling and freezing induced alterations in the physiological properties, gene transcriptional profiles and metabolite levels in the economically important red algae species, Neoporphyra haitanensis. Control samples (kept at 20 °C) were compared to chilled thalli (10 and 4 °C) and to thalli under - 4 °C conditions. Chilling stress did not affect the health or photosynthetic efficiency of gametophytes, but freezing conditions resulted in the arrest of growth, death of some cells and a decrease in photosynthetic activity as calculated by Fv/Fm. Transcriptome sequencing analysis revealed that the photosynthetic system was down-regulated along with genes associated with carbon fixation and primary metabolic biosynthesis. Adaptive mechanisms included an increase in unsaturated fatty acids levels to improve membrane fluidity, an increase in floridoside and isofloridoside content to enhance osmotic resistance, and an elevation in levels of some resistance-associated phytohormones (abscisic acid, salicylic acid, and methyl jasmonic acid). These physiochemical alterations occurred together with the upregulation of ribosome biogenesis.
N. haitanensis adopts multiple protective mechanisms to maintain homeostasis of cellular physiology in tolerance to cold stress.
紫菜属（Porphyra sensu lato）天然生长在不利的潮间带环境中，在那里它们会受到剧烈的温度波动的影响。紫菜属应对冷胁迫的策略尚未完全清楚。
本研究揭示了在经济上重要的紫菜物种坛紫菜（Neoporphyra haitanensis）中，冷胁迫和冻胁迫会引起生理特性、基因转录谱和代谢物水平的改变。将对照样品（保持在 20°C）与在 10°C 和 4°C 下冷藏的样品以及在-4°C 条件下的样品进行比较。冷胁迫不会影响配子体的健康或光合作用效率，但冻胁迫会导致生长停滞、部分细胞死亡以及根据 Fv/Fm 计算得出的光合作用活性下降。转录组测序分析表明，光合作用系统与碳固定和初级代谢物生物合成相关的基因下调。适应机制包括增加不饱和脂肪酸水平以提高膜流动性，增加岩藻糖甙和异岩藻糖甙含量以增强渗透抗性，以及一些与抗性相关的植物激素（脱落酸、水杨酸和茉莉酸甲酯）水平的升高。这些理化变化伴随着核糖体生物发生的上调。
坛紫菜通过多种保护机制来维持细胞生理的内稳态，以耐受冷胁迫。
