Low temperature induces changes in plants at physiological and molecular levels, thus affecting growth and development. The Lanzhou lily (Lilium davidii, var. unicolor) is an important medicinal plant with high economic value. However, the molecular mechanisms underlying its photosynthetic and antioxidation responses to low temperature still remain poorly understood. This study subjected the Lanzhou lily to the two temperatures of 20°C (control) and 4°C (low temperature) for 24 h. Physiological parameters related to membrane integrity, photosynthesis, antioxidant system, and differentially expressed genes were investigated. Compared with control, low temperature increased the relative electrical conductivity by 43.2%, while it decreased net photosynthesis rate, ratio of variable to maximal fluorescence, and catalase activity by 47.3%, 10.1%, and 11.1%, respectively. In addition, low temperature significantly increased the content of soluble protein, soluble sugar, and proline, as well as the activity of superoxide dismutase and peroxidase. Comparative transcriptome profiling showed that a total of 238,109 differentially expressed genes were detected. Among these, 3,566 were significantly upregulated while 2,982 were significantly downregulated in response to low temperature. Gene Ontology enrichment analysis indicated that in response to low temperature, the mostly significantly enriched differentially expressed genes were mainly involved in phosphorylation, membrane and protein kinase activity, as well as photosynthesis, light harvesting, light reaction, and alpha,alpha-trehalose-phosphate synthase activity. Kyoto Encyclopedia of Genes and Genomes enrichment analysis also indicated that the most significantly enriched pathways involved ribosome biogenesis in eukaryotes, phenylalanine metabolism, circadian rhythm, porphyrin and chlorophyll metabolism, photosynthesis of antenna proteins, photosynthesis, and carbon fixation in photosynthetic organisms. Moreover, the expression patterns of 10 randomly selected differentially expressed genes confirmed the RNA-Seq results. These results expand the understanding of the physiological and molecular mechanisms underlying the response of the Lanzhou lily to low temperature stress.

中文翻译：

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兰州百合（Lilium davidii，var。unicolor）对冷胁迫的生理和转录组学响应。

低温诱导植物在生理和分子水平上的变化，从而影响植物的生长发育。兰州百合（Lilium davidii，单色）是一种重要的药用植物，具有很高的经济价值。然而，其对低温的光合作用和抗氧化反应的分子机制仍然知之甚少。这项研究使兰州百合在20°C（对照）和4°C（低温）这两个温度下持续24小时。研究了与膜完整性，光合作用，抗氧化剂系统和差异表达基因有关的生理参数。与对照相比，低温使相对电导率提高了43.2％，同时降低了净光合速率，最大荧光变量与最大荧光比以及过氧化氢酶活性，分别降低了47.3％，10.1％，和11.1％。另外，低温显着增加了可溶性蛋白质，可溶性糖和脯氨酸的含量，以及超氧化物歧化酶和过氧化物酶的活性。比较转录组谱分析表明，总共检测到238,109个差异表达的基因。其中，响应低温，显着上调了3566个，而显着下调了2982个。基因本体富集分析表明，响应低温，最显着富集的差异表达基因主要涉及磷酸化，膜和蛋白激酶活性，以及​​光合作用，光收集，光反应和α，α-海藻糖磷酸合酶活性。京都基因与基因组百科全书》的富集分析还表明，最显着富集的途径涉及真核生物中的核糖体生物发生，苯丙氨酸代谢，昼夜节律，卟啉和叶绿素代谢，触角蛋白的光合作用，光合作用以及光合生物中的碳固定。此外，随机选择的10个差异表达基因的表达模式证实了RNA-Seq结果。这些结果扩大了对兰州百合对低温胁迫的响应的生理和分子机制的认识。和光合作用生物中的碳固定。此外，随机选择的10个差异表达基因的表达模式证实了RNA-Seq结果。这些结果扩大了对兰州百合对低温胁迫的响应的生理和分子机制的认识。和光合作用生物中的碳固定。此外，随机选择的10个差异表达基因的表达模式证实了RNA-Seq结果。这些结果扩大了对兰州百合对低温胁迫的响应的生理和分子机制的认识。