Sphingolipid metabolism is strikingly different between pollen and leaf in Arabidopsis as revealed by compositional and gene expression profiling
Sphingolipid metabolism is strikingly different between pollen and leaf in Arabidopsis as revealed by compositional and gene expression profiling
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DOI：
10.1016/j.phytochem.2015.02.019
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发表时间：
2015-07-01
期刊：
影响因子：
3.8
通讯作者：
Cahoon, Edgar B.
中科院分区：
文献类型：
--
作者：
Luttgeharm, Kyle D.;Kimberlin, Athen N.;Cahoon, Edgar B.
虽然鞘脂是必需的雄配子体发育拟南芥，鞘脂成分和生物合成基因的表达以前没有在花粉中检查。本文采用电喷雾-串联质谱（ESI-MS/MS）技术对拟南芥野生型Col-0和长链碱基（LCB）Delta 4去饱和酶突变体花粉中鞘脂的组成进行了分析。花粉组分高度富集葡萄糖神经酰胺（GlcCer）相对于先前报道的水平在叶子。伴随着Delta 4去饱和酶突变体中Delta 4不饱和LCB鞘氨二烯（d18：2）的损失，GlcCer浓度降低了50%。此外，花粉糖基肌醇磷酸神经酰胺（GIPC）被发现有一个复杂的阵列的N-乙酰基糖基化GIPC，包括物种多达三个戊糖单位，不存在于叶GIPC。在花粉的不同鞘脂组成的基础上，GlcCer和d18：2合成和代谢的关键生物合成酶的基因在花粉中比在叶或幼苗中更高地表达，包括GlcCer合酶（GCS）、鞘氨醇碱C-4羟化酶2（SBH 2）、LCB Delta 8去饱和酶（SLD 1和SLD 2）和LOH 2神经酰胺合酶（LOH 2）的基因。总体而言，这些研究结果表明显着不同的鞘脂代谢之间的花粉和叶片在拟南芥，其意义仍有待确定。(C)2015爱思唯尔有限公司版权所有。
Although sphingolipids are essential for male gametophytic development in Arabidopsis thaliana, sphingolipid composition and biosynthetic gene expression have not been previously examined in pollen. In this report, electrospray ionization (ESI)-MS/MS was applied to characterization of sphingolipid compositional profiles in pollen isolated from wild type Arabidopsis Col-0 and a long-chain base (LCB) Delta 4 desaturase mutant. Pollen fractions were highly enriched in glucosylceramides (GlcCer) relative to levels previously reported in leaves. Accompanying the loss of the Delta 4 unsaturated LCB sphingadiene (d18:2) in the Delta 4 desaturase mutant was a 50% reduction in GlcCer concentrations. In addition, pollen glycosylinositolphosphoceramides (GIPCs) were found to have a complex array of N-acetyl-glycosylated GIPCs, including species with up to three pentose units that were absent from leaf GIPCs. Underlying the distinct sphingolipid composition of pollen, genes for key biosynthetic enzymes for GlcCer and d18:2 synthesis and metabolism were more highly expressed in pollen than in leaves or seedlings, including genes for GlcCer synthase (GCS), sphingoid base C-4 hydroxylase 2 (SBH2), LCB Delta 8 desaturases (SLD1 and SLD2), and LOH2 ceramide synthase (LOH2). Overall, these findings indicate strikingly divergent sphingolipid metabolism between pollen and leaves in Arabidopsis, the significance of which remains to be determined. (C) 2015 Elsevier Ltd. All rights reserved.