Comparative Physiology of Oleaginous Species from the Yarrowia Clade

Yarrowia lipolytica is a genetically tractable yeast species that has become an attractive model for analyses of lipid metabolism, due to its oleaginous nature. We investigated the regulation and evolution of lipid metabolism in non-Saccharomycetaceae yeasts, by carrying out a comparative physiological analysis of eight species recently assigned to the Yarrowia clade: Candida alimentaria, Y. deformans, C. galli, C. hispaniensis, C. hollandica, C. oslonensis, C. phangngensis and Y. yakushimensis. We compared the abilities of type strains of these species to grow on 31 non hydrophobic (sugars and other carbohydrate compounds) and 13 hydrophobic (triglycerides, alkanes and free fatty acids) carbon sources. Limited phenotypic diversity was observed in terms of the range of substrates used and, in the case of short-chain fatty acids, their toxicity. We assessed the oleaginous nature of these species, by evaluating their ability to store and to synthesize lipids. The mean lipid content of cells grown on oleic acid differed considerably between species, ranging from 30% of cell dry weight in C. oslonensis to 67% in C. hispaniensis. Lipid synthesis in cells grown on glucose resulted in the accumulation of C18:1 (n-9) as the major compound in most species, except for C. alimentaria and Y. yakushimensis, which accumulated principally C18:2(n-6), and C. hispaniensis, which accumulated both C16:0 and C18:1(n-9). Thus, all species of the clade were oleaginous, but they presented specific patterns of growth, lipid synthesis and storage, and therefore constitute good models for the comparative analysis of lipid metabolism in this basal yeast clade.

曲霉酵母Yarrowia lipolytica是一种遗传操作便捷的酵母物种，由于其富含油脂的特性，已成为脂质代谢分析的理想模型。本研究旨在探究非酿酒酵母（Saccharomycetaceae）中脂质代谢的调控与进化，通过对归属于Yarrowia属的八种酵母物种（Candida alimentaria、Y. deformans、C. galli、C. hispaniensis、C. hollandica、C. oslonensis、C. phangngensis和Y. yakushimensis）进行生理学比较分析，以评估它们在31种非疏水性（如糖和其他碳水化合物化合物）和13种疏水性（如甘油三酯、烷烃和游离脂肪酸）碳源上的生长能力。研究发现，这些物种在底物利用范围和短链脂肪酸的毒性方面表现出有限的表型多样性。我们通过评估这些物种储存和合成脂质的能力，对其油脂性质进行了评估。在橄榄油酸培养的细胞中，不同物种的脂质含量差异显著，从C. oslonensis的细胞干重30%到C. hispaniensis的67%不等。在葡萄糖培养基中培养的细胞中，脂质合成导致大多数物种积累C18:1（n-9）作为主要成分，除了C. alimentaria和Y. yakushimensis，它们主要积累C18:2(n-6)，以及C. hispaniensis，其积累C16:0和C18:1(n-9)。因此，该属所有物种均为油脂性，但它们在生长、脂质合成和储存方面呈现出特定的模式，因此成为该基础酵母类群脂质代谢比较分析的理想模型。