Kreszies Victoria, Hoppe Nina, Gutbrod Katharina, Dörmann Peter
Institute of Molecular Physiology and Biotechnology of Plants (IMBIO), University of Bonn, 53115, Bonn, Germany.
Forest Botany and Tree Physiology, University of Göttingen, 37077, Göttingen, Germany.
Planta. 2025 Mar 20;261(4):94. doi: 10.1007/s00425-025-04670-9.
The increase in tocopherol (vitamin E) biosynthesis in Arabidopsis during drought and osmotic stress, but not during high light or nitrogen deprivation, is mediated by abscisic acid. Plants increase the production of antioxidants including tocochromanols (vitamin E) during stress. To study the regulation of tocochromanol synthesis, Arabidopsis plants were exposed to drought, osmotic stress stimulated by polyethylene glycol, abscisic acid (ABA), nitrogen deprivation, and high light. ABA treatment resulted in increased contents of tocochromanols, and expression of the key tocopherol biosynthesis genes VTE2 and HPPD was upregulated, indicating that tocochromanol accumulation was regulated by ABA. Under drought and osmotic stress, the ABA and tocochromanol contents as well as VTE2 and HPPD expression were also increased. ABA levels did not change during nitrogen deprivation or high light treatment, indicating that tocochromanol accumulation under these conditions was ABA-independent. Tocochromanol accumulation during drought or osmotic stress was not compromised in the ABA-deficient aba1-6, aba2-1 and aba3-2 mutants, suggesting that tocochromanol synthesis under these conditions was mostly regulated in an ABA-independent way. Therefore, the accumulation of tocochromanols in Arabidopsis can be regulated by ABA-dependent and ABA-independent signaling pathways, based on the specific conditions.
拟南芥在干旱和渗透胁迫期间生育酚（维生素E）生物合成增加，但在高光或氮缺乏期间则不然，这一过程由脱落酸介导。植物在胁迫期间会增加包括生育三烯酚（维生素E）在内的抗氧化剂的产生。为了研究生育三烯酚合成的调控机制，将拟南芥植株暴露于干旱、聚乙二醇刺激的渗透胁迫、脱落酸（ABA）、氮缺乏和高光条件下。ABA处理导致生育三烯酚含量增加，关键生育酚生物合成基因VTE2和HPPD的表达上调，表明生育三烯酚的积累受ABA调控。在干旱和渗透胁迫下，ABA和生育三烯酚含量以及VTE2和HPPD的表达也增加。在氮缺乏或高光处理期间，ABA水平没有变化，表明在这些条件下生育三烯酚的积累与ABA无关。在ABA缺陷型突变体aba1-6、aba2-1和aba3-2中，干旱或渗透胁迫期间生育三烯酚的积累并未受到影响，这表明在这些条件下生育三烯酚的合成主要以与ABA无关的方式进行调控。因此，根据特定条件，拟南芥中生育三烯酚的积累可由ABA依赖和ABA非依赖信号通路调控。
