牡丹(Paeoniasuffruticosa)是一种不耐高温的中国传统花卉,夏季频繁的晒伤限制了它的正常生长。对牡丹的分子机制缺乏了解,极大地限制了新型耐热品种的改良。因此,我们处理了牡丹品种“玉红”(P.suffruticosa\“Yuhong\”)在正常(25°C)和高温(40°C)下进行测序,研究对热应激的分子响应机制。通过比较转录组,总共检测到7,673个差异表达基因(DEG),包括4,220个上调基因和3,453个下调基因。功能注释表明,DEGs主要与代谢过程有关,细胞和结合,碳代谢,和内质网蛋白加工。qRT-PCR显示,三个sHSP基因(PsHSP17.8,PsHSP21和PsHSP27.4)在牡丹对热胁迫的响应中上调。转基因系(拟南芥)的组织定量显示,所有三个基因在叶片中的表达最高。经高温处理后恢复正常生长的转基因株系(PsHSP17.8、PsHSP21和PsHSP27.4)的存活率分别为43、36和31%,分别。此外,超氧化物歧化酶的活性,游离脯氨酸的积累,叶绿素水平高于野生型系,而丙二醛含量和电导率较低,野生型植物的膜脂过氧化反应更为强烈。我们的研究发现了几种与牡丹耐热性相关的过程和途径,包括代谢过程,单有机体过程,苯丙烷生物合成途径,和内质网蛋白合成途径。PsHSP17.8,PsHSP21和PsHSP27.4通过增加SOD活性和脯氨酸含量来提高耐热性。这些发现可为了解牡丹的耐热性反应提供遗传资源,有利于今后的种质创新。
Tree peony (Paeonia suffruticosa) is a traditional Chinese flower that is not resistant to high temperatures, and the frequent sunburn during summer limits its normal growth. The lack of understanding of the molecular mechanisms in tree peony has greatly restricted the improvement of novel heat-tolerant varieties. Therefore, we treated tree peony cultivar \"Yuhong\" (P. suffruticosa \"Yuhong\") at normal (25°C) and high temperatures (40°C) and sequenced the transcriptomes, to investigate the molecular responsive mechanisms to heat stress. By comparing the transcriptomes, a total of 7,673 differentially expressed genes (DEGs) were detected comprising 4,220 upregulated and 3,453 downregulated genes. Functional annotation showed that the DEGs were mainly related to the metabolic process, cells and binding, carbon metabolism, and endoplasmic reticulum protein processing. qRT-PCR revealed that three sHSP genes (PsHSP17.8, PsHSP21, and PsHSP27.4) were upregulated in the response of tree peony to heat stress. Tissue quantification of the transgenic lines (Arabidopsis thaliana) showed that all three genes were most highly expressed in the leaves. The survival rates of transgenic lines (PsHSP17.8, PsHSP21, and PsHSP27.4) restored to normal growth after high-temperature treatment were 43, 36, and 31%, respectively. In addition, the activity of superoxide dismutase, accumulation of free proline, and chlorophyll level was higher than those of the wild-type lines, while the malondialdehyde content and conductivity were lower, and the membrane lipid peroxidation reaction of the wild-type plant was more intense. Our research found several processes and pathways related to heat resistance in tree peony including metabolic process, single-organism process, phenylpropane biosynthesis pathway, and endoplasmic reticulum protein synthesis pathway. PsHSP17.8, PsHSP21, and PsHSP27.4 improved heat tolerance by increasing SOD activity and proline content. These findings can provide genetic resources for understanding the heat-resistance response of tree peony and benefit future germplasm innovation.