The herbaceous peony (Paeonia lactiflora Pall.) is renowned for its striking flowers, which are highly valued in the cut flower industry. However, in the middle and lower reaches of the Yangtze River, the elevated summer temperatures negatively affect the plant's flowering capacity in the subsequent year. 3-oxoacyl-ACP reductase (FabG) is a component of the type II fatty acid synthesis (FAS II) system, where it plays a role in facilitating the production of saturated fatty acids. However, its role in conferring resistance to high-temperature stress remains unclear. In order to investigate the function of PlFabG in dealing with high-temperature stress, we isolated PlFabG from P. lactiflora. The gene contains an open reading frame (ORF) of 780 bp, which encodes 259 amino acids. Quantitative real-time PCR (qRT-PCR) analysis showed that the expression levels of PlFabG increased with prolonged exposure to high temperature. Additionally, plants overexpressing PlFabG maintained a relatively healthy phenotype under high-temperature stress, whereas plants with silencing PlFabG exhibited more severe leaf scorching and wilting under the same conditions. Various physiological indices indicated that PlFabG reduced reactive oxygen species (ROS) accumulation and enhanced the saturation of photosystem II. Most importantly, PlFabG helped P. lactiflora withstand high-temperature stress by increasing the proportion of saturated fatty acids, thereby maintaining cell membrane integrity. These findings elucidate the beneficial role of PlFabG in enhancing plant tolerance to high temperature and provide a strong theoretical support for the development of high-temperature tolerance in transgenic P. lactiflora.

中文翻译：

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PlFabG 通过增加饱和脂肪酸提高草本牡丹的耐高温性


草本牡丹 （Paeonia lactiflora Pall） 以其醒目的花朵而闻名，在切花行业中受到高度重视。然而，在长江中下游，夏季高温对植物下一年的开花能力产生了负面影响。3-氧酰基-ACP 还原酶 （FabG） 是 II 型脂肪酸合成 （FAS II） 系统的一个组成部分，它在促进饱和脂肪酸的产生中发挥作用。然而，它在赋予抵抗高温应力方面的作用仍不清楚。为了研究 PlFabG 在应对高温胁迫中的功能，我们从 P. lactiflora 中分离了 PlFabG。该基因包含一个 780 bp 的开放阅读框 （ORF），编码 259 个氨基酸。实时定量 PCR （qRT-PCR） 分析显示，PlFabG 的表达水平随着高温暴露时间的延长而升高。此外，过表达 PlFabG 的植株在高温胁迫下保持相对健康的表型，而沉默 PlFabG 的植株在相同条件下表现出更严重的叶片焦化和枯萎。各种生理指标表明，PlFabG 减少了活性氧 （ROS） 积累并增强了光系统 II 的饱和度。最重要的是，PlFabG 通过增加饱和脂肪酸的比例来帮助 P. lactiflora 承受高温胁迫，从而维持细胞膜的完整性。这些发现阐明了 PlFabG 在增强植物耐高温方面的有益作用，为转基因乳花紫草耐高温性的发展提供了有力的理论支持。