背景:泡桐,一种原产于中国的具有生态和经济价值的植物,以其优良的木材质量和强大的适应性而著称。其中,紫杉具有在寒冷气候中生存的能力,与中国北方有关的特征。然而,其耐寒性的分子信息尚未被探索。本研究旨在研究冷暴露后紫杉的生理指标和转录水平的变化。这可以为揭示中低温(MLT)和极端低温(ELT)之间诱导生理扰动的遗传基础是否存在差异提供证据。
结果:在不同程度的低温胁迫下,生理指标的检测显示出相似的变化模式。渗透调节物质的积累增强,如可溶性糖和可溶性蛋白质,与MLT相比,ELT在紫杉中更有利。此外,暴露于ELT48小时后,我们观察到明显的枯萎症状,而MLT暴露48小时后这种效果不明显。MLT和ELT之间的比较转录组分析显示13,688个差异表达基因(DEGs),大多数在治疗12小时和48小时后出现。GO和KEGG分析阐明了芳香族L-氨基酸脱羧酶活性术语和碳水化合物代谢途径的显着富集。因此,推测参与上述过程的DEGs可能与MLT和ELT之间可溶性蛋白质和可溶性糖含量的差异有关。时间序列聚类分析进一步强调了参与“糖基转移酶”的几个关键基因,半乳糖代谢和淀粉和蔗糖代谢途径以及酪氨酸脱羧酶活性术语。例如,纤维素合成酶样A(CLSA2/9),棉子糖合酶(RafS2),β-淀粉酶(BAM1)和酪氨酸/DOPA脱羧酶(TYDC1/2/5)基因,MLT和ELT之间的表达趋势不同,可能会显着影响紫杉中可溶性糖和可溶性蛋白质的丰度。
结论:在MLT和ELT治疗之间,部分重叠的反应途径的紫杉被鉴定,而几个调节渗透调节物质积累的基因具有不同的表达模式。这些发现可以为紫杉适应复杂的低温生境提供新的生理和分子视角。
BACKGROUND: Paulownia, an ecologically and economically valuable plant species native to China, is notable for its excellent timber quality and strong adaptability. Among them, Paulownia catalpifolia displays the ability to survive in cold climate, a trait associated with northern China. Yet, the molecular information for its cold-tolerance has not been explored. This study was to investigate the changes in physiological indices and transcript levels of P. catalpifolia following cold exposure, which could provide evidence for revealing whether there were differences in the genetic basis of inducing physiological perturbations between moderate low temperature (MLT) and extreme low temperature (ELT).
RESULTS: The detection of physiological indices under diverse degrees of chilling stress showed similar patterns of alteration. Enhanced accumulation of osmoregulatory substances, such as soluble sugar and soluble protein, were more conducive under ELT compared to MLT in P. catalpifolia. Moreover, we observed leaf wilting symptoms distinctly after exposure to ELT for 48 h, while this effect was not obvious after MLT exposure for 48 h. Comparative transcriptomic analysis between MLT and ELT demonstrated 13,688 differentially expressed genes (DEGs), most of them appeared after 12 h and 48 h of treatment. GO and KEGG analyses elucidated prominent enrichment in aromatic-L-amino-acid decarboxylase activity term and carbohydrate metabolism pathways. Therefore, it was speculated that the DEGs involved in the above processes might be related to the difference in the contents of soluble protein and soluble sugar between MLT and ELT. Time series clustering analyses further highlighted several key genes engaged in the \'Glycosyltransferases\', \'Galactose metabolism\' and \'Starch and sucrose metabolism\' pathways as well as the \'tyrosine decarboxylase activity\' term. For instance, cellulose synthase-like A (CLSA2/9), raffinose synthase (RafS2), β-amylase (BAM1) and tyrosine/DOPA decarboxylase (TYDC1/2/5) genes, diverging in their expression trends between MLT and ELT, might significantly affect the soluble sugar and soluble protein abundance within P. catalpifolia.
CONCLUSIONS: Between MLT and ELT treatments, partial overlaps in response pathways of P. catalpifolia were identified, while several genes regulating the accumulation of osmotic adjustment substances had disparate expression patterns. These findings could provide a novel physiological and molecular perspective for P. catalpifolia to adapt to complex low temperature habitats.