Storage oil breakdown during embryo development of Brassica napus (L.)
Storage oil breakdown during embryo development of Brassica napus (L.)
复制标题
DOI：
10.1093/jxb/eri129
复制
发表时间：
2005-05-01
影响因子：
6.9
通讯作者：
Rawsthorne, S
中科院分区：
文献类型：
--
作者：
Chia, TYP;Pike, MJ;Rawsthorne, S
本研究表明，甘蓝型油菜（Brassica napus（L.））发育胚的主要贮藏产物中至少有10%，三酰基甘油在种子发育的干燥阶段损失。这种脂质的代谢进行了研究，从[1-C-14]癸酸提供给离体胚胎的标记的命运的测量，并通过测量的脂肪酸catenase的酶的活性。对脱水胚的测量与对脂质积累过程中的胚和发芽幼苗的测量进行了比较。β-氧化和乙醛酸循环，磷酸烯醇式丙酮酸羧激酶的酶存在于胚油积累过程中，随着种子成熟和干燥，活性和丰度增加。虽然活动小于发芽过程中测量，他们至少在体内的脂肪酸合成率在胚胎发育过程中。标记的模式，以下的癸酸代谢的孤立的胚胎，表明更大的参与乙醛酸循环在干燥过程中比早期的石油积累，并表明，大部分的C-14-标记从癸酸被释放为CO2在这两个阶段。在胚胎发育过程中，蔗糖不是癸酸代谢的产物，因此脂质降解与净脂肪生成活性无关。这些观察结果进行了讨论的背景下，种子发育，油产量，和植物中的新型脂肪酸的合成。
In this study it is shown that at least 10% of the major storage product of developing embryos of Brassica napus (L.), triacylglycerol, is lost during the desiccation phase of seed development. The metabolism of this lipid was studied by measurements of the fate of label from [1-C-14]decanoate supplied to isolated embryos, and by measurements of the activities of enzymes of fatty acid catabolism. Measurements on desiccating embryos have been compared with those made on embryos during lipid accumulation and on germinating seedlings. Enzymes of beta-oxidation and the glyoxylate cycle, and phosphoenolpyruvate carboxykinase were present in embryos during oil accumulation, and increased in activity and abundance as the seeds matured and became desiccated. Although the activities were less than those measured during germination, they were at least comparable to the in vivo rate of fatty acid synthesis in the embryo during development. The pattern of labelling, following metabolism of decanoate by isolated embryos, indicated a much greater involvement of the glyoxylate cycle during desiccation than earlier in oil accumulation, and showed that much of the C-14-label from decanoate was released as CO2 at both stages. Sucrose was not a product of decanoate metabolism during embryo development, and therefore lipid degradation was not associated with net gluconeogenic activity. These observations are discussed in the context of seed development, oil yield, and the synthesis of novel fatty acids in plants.