Chiron Hélène, Wilmer Jeroen, Lucas Marie-Odile, Nesi Nathalie, Delseny Michel, Devic Martine, Roscoe Thomas J
Laboratoire Genome et Developpement des Plantes, CNRS-UP UMR5096, Université de Perpignan, 52 Avenue Paul Alduy, 66860, Perpignan, France.
Plant Mol Biol. 2015 May;88(1-2):65-83. doi: 10.1007/s11103-015-0309-y. Epub 2015 Mar 21.
The expression of the FATTY ACID ELONGATION1 genes was characterised to provide insight into the regulation of very long chain fatty acid (VLCFA) biosynthesis in Brassica napus embryos. Each of the two rapeseed homoeologous genes (Bn-FAE1.1 and Bn-FAE1.2) encoding isozymes of 3-keto-acylCoA synthase, a subunit of the cytoplasmic acyl-CoA elongase complex that controls the production of elongated fatty acids, are expressed predominantly in developing seeds. The proximal regions of the Bn-FAE1.1 and Bn-FAE1.2 promoters possess strong sequence identity suggesting that transcriptional control of expression is mediated by this region which contains putative cis-elements characteristic of those found in the promoters of genes expressed in embryo and endosperm. Histochemical staining of rapeseed lines expressing Bn-FAE1.1 promoter:reporter gene fusions revealed a strong expression in the embryo cotyledon and axis throughout the maturation phase. Quantitative analyses revealed the region, -331 to -149, exerts a major control on cotyledon specific expression and the level of expression. A second region, -640 to -475, acts positively to enhance expression levels and extends expression of Bn-FAE1.1 into the axis and hypocotyl but also acts negatively to repress expression in the root meristem. The expression of the Bn-FAE1.1 gene was not restricted to the seed but was also detected in the vascular tissues of germinating seedlings and mature plants in the fascicular cambium tissue present in roots, stem and leaf petiole. We propose that Bn-FAE1.1 expression in vascular tissue may contribute VLCFA for barrier lipid synthesis and reflects the ancestral function of FAE1 encoded 3-keto-acylCoA synthase.
对脂肪酸延长酶1基因的表达进行了表征，以深入了解甘蓝型油菜胚胎中极长链脂肪酸（VLCFA）生物合成的调控机制。两个油菜同源基因（Bn-FAE1.1和Bn-FAE1.2），它们编码3-酮酰基辅酶A合酶的同工酶，该酶是细胞质酰基辅酶A延长酶复合体的一个亚基，控制着延长脂肪酸的产生，主要在发育中的种子中表达。Bn-FAE1.1和Bn-FAE1.2启动子的近端区域具有很强的序列同一性，这表明表达的转录控制是由该区域介导的，该区域包含在胚胎和胚乳中表达的基因启动子中发现的推定顺式元件的特征。对表达Bn-FAE1.1启动子：报告基因融合体的油菜品系进行组织化学染色，发现在整个成熟阶段，胚胎子叶和轴中都有强烈表达。定量分析表明，-331至-149区域对子叶特异性表达和表达水平起主要控制作用。第二个区域-640至-475起正向作用以增强表达水平，并将Bn-FAE1.1的表达扩展到轴和下胚轴，但也起负向作用以抑制根分生组织中的表达。Bn-FAE1.1基因的表达不仅限于种子，还在发芽幼苗和成熟植株的维管组织中被检测到，这些维管组织存在于根、茎和叶柄中的束状形成层组织中。我们提出，Bn-FAE1.1在维管组织中的表达可能为屏障脂质合成贡献VLCFA，并反映了FAE1编码的3-酮酰基辅酶A合酶的原始功能。
