Proline is one of the most important compatible osmolyte in cells, which accumulates in response to various stresses, including salt, water deficit, heavy metal, pathogen infection and extreme temperature. In this study, a growth chamber was employed to simulate heat environment for Avicennia marina seedlings. We detected some physiological indices in the leaves of A. marina at 40 °C, including the activity of delta-1-pyrroline-5-carboxylate synthase (P5CS), the content of free proline and soluble protein, transpiration rate and membrane permeability, and discussed the relationship between these five indices and heat resistant ability. And then a P5CS gene was cloned from A. marina using homologous cloning and rapid amplification of cDNA ends methods. It was designated as AmP5CS, encoding a protein that contained a feedback inhibition site of proline, proA, proB, conserved Leu zipper, GSA-DH domain and other functional domains of P5CS protein in high plants. Expression analysis of AmP5CS gene indicated it was involved in heat stress response. It is the first time that P5CS from A. marina has been cloned and the findings laid the foundation of figuring out heat resistant mechanisms and relieving heat damage, which is significant during global warming.

中文翻译：

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高温胁迫下红树林Avicennia滨海地区AmP5CS的脯氨酸代谢和分子克隆。

脯氨酸是细胞中最重要的相容性渗透压剂之一，可响应各种压力而累积，包括盐，水分缺乏，重金属，病原体感染和极端温度。在这项研究中，采用了一个生长室来模拟Avicennia marina幼苗的热环境。我们在40°C的条件下检测了滨海曲霉叶片的一些生理指标，包括δ-1-吡咯啉-5-羧酸合酶（P5CS）的活性，脯氨酸和可溶性蛋白的含量，蒸腾速率和膜通透性，并讨论了这五个指标与耐热性能之间的关系。然后使用同源克隆和cDNA末端快速扩增方法从滨海曲霉中克隆出P5CS基因。它被指定为AmP5CS，编码含有高植物中脯氨酸，proA，proB，保守的亮拉链，GSA-DH域和P5CS蛋白其他功能域的反馈抑制位点的蛋白质。AmP5CS基因的表达分析表明它参与了热应激反应。这是首次克隆来自滨海假单胞菌的P5CS，这一发现为弄清耐热机制和减轻热损害奠定了基础，这在全球变暖中具有重要意义。