ZIK plasmatis, Leibniz Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Str. 2, 17489, Greifswald, Germany.
Institute of Botany & Landscape Ecology, Greifswald University, Soldmannstr. 15, 17489, Greifswald, Germany.
BMC Plant Biol. 2024 Sep 30;24(1):909. doi: 10.1186/s12870-024-05578-4.
Plants are designed to endure stress, but increasingly extreme weather events are testing the limits. Events like flooding result in submergence of plant organs, triggering an energy crisis due to hypoxia and threaten plant growth and productivity. Lipids are relevant as building blocks and energy vault and are substantially intertwined with primary metabolism, making them an ideal readout for plant stress.
By high resolution mass spectrometry, a distinct, hypoxia-related lipid composition of Solanum lycopersicum root tissue was observed. Out of 491 lipid species, 11 were exclusively detected in this condition. Among the lipid classes observed, glycerolipids and glycerophospholipids dominated by far (78%). Differences between the lipidomic profiles of both analyzed conditions were significantly driven by changes in the abundance of triacylglycerols (TGs) whereas sitosterol esters, digalactosyldiacylglycerols, and phosphatidylcholine play a significantly negligible role in separation. Alongside, an increased level of polyunsaturation was observed in the fatty acid chains, with 18:2 and 18:3 residues showing a significant increase. Of note, hexadecatetraenoic acid (16:4) was identified in hypoxia condition samples. Changes in gene expression of enzymes related to lipid metabolism corroborate the above findings.
To our knowledge, this is the first report on a hypoxia-induced increase in TG content in tomato root tissue, closing a knowledge gap in TG abiotic stress response. The results suggest that the increase in TGs and TG polyunsaturation degree are common features of hypoxic response in plant roots.
植物被设计为能够承受压力，但日益极端的天气事件正在考验它们的极限。例如洪水等事件会导致植物器官被淹没，从而引发缺氧引起的能量危机，并威胁植物的生长和生产力。脂质作为构建块和能量库与初级代谢密切相关，因此是植物应激的理想指标。
通过高分辨率质谱分析，观察到番茄根组织中存在一种与缺氧相关的独特脂质组成。在 491 种脂质中，有 11 种仅在这种情况下被检测到。在所观察到的脂质中，甘油酯和甘油磷脂占据绝对主导地位（78%）。两种分析条件下的脂质组学图谱之间的差异主要由三酰基甘油（TAGs）丰度的变化驱动，而甾醇酯、二半乳糖基二酰基甘油和磷脂酰胆碱在分离中作用微不足道。此外，脂肪酸链中的多不饱和程度增加，18:2 和 18:3 残基显著增加。值得注意的是，在缺氧条件下的样品中鉴定出了十六碳四烯酸（16:4）。与脂质代谢相关的酶的基因表达变化证实了上述发现。
据我们所知，这是第一个关于番茄根组织中缺氧诱导 TG 含量增加的报告，填补了 TG 非生物胁迫响应知识空白。研究结果表明，TAG 含量增加和 TG 多不饱和程度增加是植物根系缺氧反应的共同特征。
