Cawthron Institute, Private Bag 2, Nelson, 7042, New Zealand; School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand.
Cawthron Institute, Private Bag 2, Nelson, 7042, New Zealand.
Cryobiology. 2024 Mar;114:104855. doi: 10.1016/j.cryobiol.2024.104855. Epub 2024 Jan 30.
The Symbiodinium genus is ancestral among other Symbiodiniaceae lineages with species that are both symbiotic and free living. Changes in marine ecosystems threaten their existence and crucial ecological roles. Cryopreservation offers an avenue for their long-term storage for future habitat restoration after coral bleaching. In our previous study we demonstrated that high salinity treatments of Symbiodiniaceae isolates led to changes in their fatty acid (FA) profiles and higher cell viabilities after cryopreservation. In this study, we investigated the role of increased salinity on FA production and the genes involved in FA biosynthesis and degradation pathways during the cryopreservation of Symbiodinium pilosum. Overall, there was a twofold increase in mass of FAs produced by S. pilosum after being cultured in medium with increased salinity (54 parts per thousand; ppt). Dimethyl sulfoxide (MeSO) led to a ninefold increase of FAs in standard salinity (SS) treatment, compared to a fivefold increase in increased salinity (IS) treatments. The mass of the FA classes returned to baseline during recovery. Transcriptomic analyses showed an acyl carrier protein gene was significantly upregulated after MeSO treatment in the SS cultures. Cytochrome P450 reductase genes were significantly down regulated after MeSO addition in SS treatment preventing FA degradation. These changes in the expression of FA biosynthesis and degradation genes contributed to more FAs in SS treated isolates. Understanding how increased salinity changes FA production and the roles of specific genes in regulating FA pathways will help improve current freezing protocols for Symbiodiniaceae and other marine microalgae.
共生藻属是其他共生藻科谱系的祖先，其物种既有共生的也有自由生活的。海洋生态系统的变化威胁着它们的生存和关键的生态作用。冷冻保存为它们提供了长期储存的途径，以便在珊瑚白化后用于未来的栖息地恢复。在我们之前的研究中，我们证明了高盐度处理共生藻分离物会导致它们的脂肪酸（FA）谱发生变化，并在冷冻保存后提高细胞活力。在这项研究中，我们研究了增加盐度对共生藻属 Pilosum 冷冻保存过程中 FA 产生和参与 FA 生物合成和降解途径的基因的作用。总的来说，在高盐度（54 个千分比）培养基中培养的共生藻属 Pilosum 产生的 FA 质量增加了两倍。与在高盐度（IS）处理中增加五倍相比，二甲亚砜（MeSO）导致标准盐度（SS）处理中的 FA 增加了九倍。在恢复过程中，FA 类的质量恢复到基线。转录组分析显示，SS 培养物中 MeSO 处理后酰基辅酶 A 蛋白基因显著上调。SS 处理中添加 MeSO 后，细胞色素 P450 还原酶基因显著下调，防止 FA 降解。FA 生物合成和降解基因表达的这些变化导致 SS 处理的分离物中产生更多的 FA。了解增加盐度如何改变 FA 产生以及特定基因在调节 FA 途径中的作用将有助于改进当前用于共生藻科和其他海洋微藻的冷冻保存方案。
