Data from: Label-free in situ imaging of oil body dynamics and chemistry in germination

Plant oleosomes are uniquely emulsified lipid reservoirs that serve as the primary energy source during seed germination. These oil bodies undergo significant changes regarding their size, composition and structure during normal seedling development; however, a detailed characterization of these oil body dynamics, which critically affect oil body extractability and nutritional value, has remained challenging because of a limited ability to monitor oil body location and composition during germination in situ. Here, we demonstrate via in situ, label-free imaging that oil bodies are highly dynamic intracellular organelles that are morphologically and biochemically remodelled extensively during germination. Label-free, coherent Raman microscopy (CRM) combined with bulk biochemical measurements revealed the temporal and spatial regulation of oil bodies in native soya bean cotyledons during the first eight days of germination. Oil bodies undergo a cycle of growth and shrinkage that is paralleled by lipid and protein compositional changes. Specifically, the total protein concentration associated with oil bodies increases in the first phase of germination and subsequently decreases. Lipids contained within the oil bodies change in saturation and chain length during germination. Our results show that CRM is a well-suited platform to monitor in situ lipid dynamics and local chemistry and that oil bodies are actively remodelled during germination. This underscores the dynamic role of lipid reservoirs in plant development.

植物油体（plant oleosomes）是一类独特的乳化脂质储库，可作为种子萌发过程中的主要能量来源。在正常幼苗发育过程中，这类油体的尺寸、组成与结构均会发生显著变化；然而，由于难以在萌发过程中原位（in situ）监测油体的位置与组成，对其动态特征的精准表征——这一特征会显著影响油体的提取效率与营养价值——长期以来颇具挑战。本研究通过原位无标记成像技术证实，油体是一类高度动态的细胞内细胞器，在萌发过程中会经历广泛的形态与生化重塑。研究人员借助无标记相干拉曼显微镜（coherent Raman microscopy，CRM）结合整体生化检测技术，揭示了萌发前8天内天然大豆子叶中油体的时空调控规律。油体经历生长与收缩的循环过程，这一过程与脂质和蛋白质的组成变化同步发生。具体而言，与油体结合的总蛋白浓度在萌发初期上升，随后下降；油体内部所含脂质的饱和度与碳链长度在萌发过程中发生改变。本研究结果表明，CRM是监测原位脂质动态与局部化学特征的理想平台，且油体在萌发过程中会被主动重塑。这一发现凸显了脂质储库在植物发育过程中的动态功能。