Kourani Mariam, Anastasiadi Maria, Hammond John P, Mohareb Fady
The Bioinformatics Group, Centre for Soil, Agrifood and Biosciences (SABS), Cranfield University, Cranfield, United Kingdom.
School of Agriculture, Policy and Development, University of Reading, Reading, United Kingdom.
Front Plant Sci. 2025 May 9;16:1507338. doi: 10.3389/fpls.2025.1507338. eCollection 2025.
Oilseed rape (), one of the most important sources of vegetable oil worldwide, is adversely impacted by heatwave-induced temperature stress especially during its yield-determining reproductive stages. However, the underlying molecular and biochemical mechanisms are still poorly understood. In this study, we investigated the transcriptomic and metabolomic responses to heat stress in plants exposed to a gradual increase in temperature reaching 30°C in the day and 24°C at night for a period of 6 days. High-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) was used to quantify the content of carbohydrates and glucosinolates, respectively. Results showed that heat stress reduced yield and altered oil composition. Heat stress also increased the content of carbohydrate (glucose, fructose, and sucrose) and aliphatic glucosinolates (gluconapin and progoitrin) in the leaves but decreased the content of the indolic glucosinolate (glucobrassicin). RNA-Seq analysis of flower buds showed a total of 1,892, 3,253, and 4,553 differentially expressed genes at 0, 1, and 2 days after treatment (DAT) and 4,165 and 1,713 at 1 and 7 days of recovery (DOR), respectively. Heat treatment resulted in downregulation of genes involved in respiratory metabolism, namely, glycolysis, pentose phosphate pathway, citrate cycle, and oxidative phosphorylation especially after 48 h of heat stress. Other downregulated genes mapped to sugar transporters, nitrogen transport and storage, cell wall modification, and methylation. In contrast, upregulated genes mapped to small heat shock proteins (sHSP20) and other heat shock factors that play important roles in thermotolerance. Furthermore, two genes were chosen from the pathways involved in the heat stress response to further examine their expression using real-time RT-qPCR. The global transcriptome profiling, integrated with the metabolic analysis in the study, shed the light on key genes and metabolic pathways impacted and responded to abiotic stresses exhibited as a result of exposure to heat waves during flowering. DEGs and metabolites identified through this study could serve as important biomarkers for breeding programs to select cultivars with stronger resistance to heat. In particular, these biomarkers can form targets for various crop breeding and improvement techniques such as marker-assisted selection.
油菜是全球最重要的植物油来源之一，尤其在其决定产量的生殖阶段，会受到热浪引发的温度胁迫的不利影响。然而，其潜在的分子和生化机制仍知之甚少。在本研究中，我们调查了在白天温度逐渐升高至30°C且夜间温度为24°C的条件下处理6天的油菜植株对热胁迫的转录组和代谢组反应。分别使用高效液相色谱（HPLC）和液相色谱 - 质谱联用（LC - MS）来定量碳水化合物和硫代葡萄糖苷的含量。结果表明，热胁迫降低了产量并改变了油的成分。热胁迫还增加了叶片中碳水化合物（葡萄糖、果糖和蔗糖）和脂肪族硫代葡萄糖苷（葡萄糖异硫氰酸酯和前甲状腺肿素）的含量，但降低了吲哚族硫代葡萄糖苷（葡萄糖芸苔素）的含量。对花芽的RNA测序分析显示，在处理后0、1和2天（DAT）分别有1892、3253和4553个差异表达基因，在恢复1天和7天（DOR）时分别有4165和1713个差异表达基因。热处理导致参与呼吸代谢的基因下调，即糖酵解、磷酸戊糖途径、柠檬酸循环和氧化磷酸化，尤其是在热胁迫48小时后。其他下调的基因涉及糖转运蛋白、氮转运和储存、细胞壁修饰以及甲基化。相反，上调的基因涉及小热激蛋白（sHSP20）和其他在耐热性中起重要作用的热激因子。此外，从热胁迫反应涉及的途径中选择了两个基因，使用实时RT - qPCR进一步检测它们的表达。本研究中的全球转录组分析与代谢分析相结合，揭示了开花期间因热浪暴露而受到影响并对非生物胁迫产生反应的关键基因和代谢途径。通过本研究鉴定的差异表达基因和代谢物可作为育种计划中选择耐热性更强品种的重要生物标志物。特别是，这些生物标志物可成为各种作物育种和改良技术（如标记辅助选择）的目标。
