Université des Sciences et de la Technologie Houari Boumedienne, Faculté des Sciences Biologiques, Bab Ezzouar, Alger, Algeria.
J Agric Food Chem. 2009 Dec 9;57(23):11434-40. doi: 10.1021/jf902525n.
Norflurazon is a bleaching herbicide known to block carotenoid biosynthesis by inhibiting phytoene desaturase activity. Soybean plants were treated with norflurazon, and we examined the effects on the desaturation of lipid molecular species in leaves using ammonium [1-(14)C] oleate labeling. In monogalactosyldiacylglycerol (MGDG), the main chloroplast lipid, a decrease in 18:3/18:3 molecular species and an increase in its precursors 18:2/18:3 and 18:2/18:2 were observed suggesting that the omega(3) FAD7 desaturase activity in planta was inhibited by norflurazon. The in vitro activity of MGDG synthase was also inhibited by 69%. In contrast, the amount of 18:3/18:3 molecular species of phosphatidylcholine (PC) in the extraplastid compartment increased. The observed increase in in vitro lysoPC-acyltransferase activity and activation of desaturation of [1-(14)C] oleate suggest that extraplastid omega(3)FAD3 desaturase was activated. Analysis of the expression of omega(3) FAD3 and omega(3) FAD7 genes in norflurazon treated plants indicate that omega(3) FAD7 and omega(3) FAD3 desaturases are controlled at the post-transcriptional level.
氟草定是一种漂白除草剂，已知通过抑制质体烯醇酶活性来阻断类胡萝卜素的生物合成。用氟草定处理大豆植株，并使用铵[1-（14）C]油酸标记来研究其对叶片中脂质分子物种去饱和的影响。在单半乳糖二酰基甘油（MGDG）中，主要的叶绿体脂质，18:3/18:3 分子物种减少，其前体 18:2/18:3 和 18:2/18:2 增加，表明氟草定抑制了植物中的ω（3）FAD7 去饱和酶活性。MGDG 合酶的体外活性也被抑制了 69%。相比之下，质体外部隔室中 18:3/18:3 分子物种的磷脂酰胆碱（PC）的量增加。体外溶血磷脂酰胆碱酰基转移酶活性的观察增加和[1-（14）C]油酸的去饱和激活表明，质体外部的ω（3）FAD3 去饱和酶被激活。在氟草定处理的植物中ω（3）FAD3 和 ω（3）FAD7 基因的表达分析表明，ω（3）FAD7 和 ω（3）FAD3 去饱和酶在转录后水平受到控制。
