Institut de Biologie de l'Ecole Normale Supérieure (IBENS), CNRS UMR8197 INSERM U1024, Ecole Normale Supérieure, 46 rue d'Ulm, 75230 Paris Cedex 05, France.
Protist. 2011 Jul;162(3):462-81. doi: 10.1016/j.protis.2011.02.002. Epub 2011 May 20.
Over the last decades Phaeodactylum tricornutum has become a model to study diatom biology at the molecular level. Cells have the peculiarity to be pleiomorphic and it is thought that this character is triggered by culture conditions, although few quantitative studies have been performed and nothing is known at the molecular level. Our aim was to quantify the effect of growth conditions on cell morphology of different P. tricornutum strains by quantitative microscopy, cellular imaging, and non-targeted transcriptomics. We show that morphotype changes can be regulated by changing culture conditions, depending on the strain, and show a common trend of increased oval cell abundance as a response to stress. Examination of expressed sequence tags (ESTs) from triradiate cells infers the importance of osmoregulation in the maintenance of this morphotype, whereas ESTs derived from oval cells grown in hyposaline and low temperature conditions show a predominance of genes encoding typical components of stress pathways, especially in signaling, cell homeostasis and lipid metabolism. This work contributes to better understand the importance of the unique capability of morphotype conversion in P. tricornutum and its relevance in acclimation to changing environmental conditions.
在过去的几十年里，三角褐指藻已成为在分子水平上研究硅藻生物学的模式生物。细胞具有多形性的特点，尽管已经进行了一些定量研究，但人们认为这种特征是由培养条件引发的，目前仍不清楚其在分子水平上的机制。我们的目的是通过定量显微镜、细胞成像和非靶向转录组学来量化不同三角褐指藻菌株的生长条件对细胞形态的影响。我们表明，形态变化可以通过改变培养条件来调节，这取决于菌株，并显示出一种共同的趋势，即作为应激反应的结果，椭圆形细胞的丰度增加。对三叶细胞的表达序列标签（ESTs）的检查推断出渗透压调节在维持这种形态的重要性，而在低盐和低温条件下生长的椭圆形细胞的 ESTs 显示出编码应激途径典型成分的基因占主导地位，尤其是在信号转导、细胞内稳态和脂质代谢方面。这项工作有助于更好地理解三角褐指藻独特的形态转换能力的重要性及其在适应不断变化的环境条件方面的相关性。
