Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, Goettingen, Germany.
Goettingen Metabolomics and Lipidomics Laboratory, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Goettingen, Germany.
Nat Plants. 2021 Feb;7(2):219-232. doi: 10.1038/s41477-020-00844-3. Epub 2021 Jan 25.
For plants, acclimation to low temperatures is fundamental to survival. This process involves the modification of lipids to maintain membrane fluidity. We previously identified a new cold-induced putative desaturase in Physcomitrium (Physcomitrella) patens. Lipid profiles of null mutants of this gene lack sphingolipids containing monounsaturated C24 fatty acids, classifying the new protein as sphingolipid fatty acid denaturase (PpSFD). PpSFD mutants showed a cold-sensitive phenotype as well as higher susceptibility to the oomycete Pythium, assigning functions in stress tolerance for PpSFD. Ectopic expression of PpSFD in the Atads2.1 (acyl coenzyme A desaturase-like 2) Arabidopsis thaliana mutant functionally complemented its cold-sensitive phenotype. While these two enzymes catalyse a similar reaction, their evolutionary origin is clearly different since AtADS2 is a methyl-end desaturase whereas PpSFD is a cytochrome b fusion desaturase. Altogether, we suggest that adjustment of membrane fluidity evolved independently in mosses and seed plants, which diverged more than 500 million years ago.
对于植物来说，适应低温是生存的基础。这一过程涉及到对脂质的修饰，以维持膜的流动性。我们之前在藓类植物 Physcomitrella patens 中鉴定出一种新的低温诱导的假定去饱和酶。该基因的缺失突变体的脂质图谱缺乏含有单不饱和 C24 脂肪酸的鞘脂，这将新蛋白归类为鞘脂脂肪酸变性酶（PpSFD）。PpSFD 突变体表现出对低温敏感的表型以及对卵菌 Pythium 的更高敏感性，这赋予了 PpSFD 在应激耐受中的功能。在拟南芥 Atads2.1（酰基辅酶 A 去饱和酶样 2）突变体中异位表达 PpSFD 可在功能上弥补其对低温敏感的表型。虽然这两种酶催化相似的反应，但它们的进化起源显然不同，因为 AtADS2 是一个甲基末端去饱和酶，而 PpSFD 是一个细胞色素 b 融合去饱和酶。总的来说，我们认为，在苔藓植物和种子植物中，膜流动性的调节是独立进化的，它们的分化发生在 5 亿多年前。
