Deposition and localization of lipid polyester in developing seeds of Brassica napus and Arabidopsis thaliana
Deposition and localization of lipid polyester in developing seeds of Brassica napus and Arabidopsis thaliana
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DOI：
10.1111/j.1365-313x.2007.03348.x
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发表时间：
2008-02-01
期刊：
影响因子：
7.2
通讯作者：
Pollard, Mike
中科院分区：
文献类型：
--
作者：
Molina, Isabel;Ohlrogge, John B.;Pollard, Mike
拟南芥和甘蓝型油菜的成熟种子含有由不可提取的脂肪聚酯衍生的脂肪族单体的复杂混合物。大多数单体沉积在种皮中，它们的组成表明角质层和Suberin层的存在。这些聚酯在种皮中的位置，以及它们对种皮渗透性和其他功能特性的贡献尚不清楚。对甘蓝型油菜种子发育过程中的聚酯沉积进行了跟踪，观察到了单体积累的不同时间模式。叶片角质蛋白的主要单体十八碳二烯-1，18-二酸酯被瞬时沉积。相反，饱和二元酸在种子干燥过程中保持不变，而脂肪醇和饱和欧米伽-羟基脂肪酸持续增加。对油菜种皮的解剖和分析表明，羽化并不是合点所特有的。对拟南芥ap2-7突变体的分析表明，Suberin单体优先与外被相关。对几个与聚酯生物合成相关的基因敲除突变体(att1、FatB和gpat5)进行了种子单体载量和组成的检测。这些突变体在聚酯单体中的差异与染料渗透分析有关。此外，稳定表达启动子：：YFP的转基因植株在内珠被中显示ATT1启动子活性，而在外珠被中显示GPAT5启动子活性。总之，拟南芥的数据表明，外层种皮有一层纤维化层，而内层种皮有一层角质状的聚酯层。
Mature seeds of Arabidopsis thaliana and Brassica napus contain complex mixtures of aliphatic monomers derived from non-extractable lipid polyesters. Most of the monomers are deposited in the seed coat, and their compositions suggest the presence of both cutin and suberin layers. The location of these polyesters within the seed coat, and their contributions to permeability of the seed coat and other functional properties are unknown. Polyester deposition was followed over Brassica seed development and distinct temporal patterns of monomer accumulation were observed. Octadecadiene-1,18-dioate, the major leaf cutin monomer, was transiently deposited. In contrast, the saturated dicarboxylates maintained a constant level during seed desiccation, whereas the fatty alcohols and saturated omega-hydroxy fatty acids continually increased. Dissection and analysis of Brassica seed coats showed that suberization is not specific to the chalaza. Analysis of the Arabidopsis ap2-7 mutant suggested that suberin monomers are preferentially associated with the outer integument. Several Arabidopsis knockout mutant lines for genes involved in polyester biosynthesis (att1, fatB and gpat5) were examined for seed monomer load and composition. The variance in polyester monomers of these mutants is correlated with dye penetration assays. Furthermore, stable transgenic plants expressing promoter:: YFP fusions showed ATT1 promoter activity in the inner integument, whereas GPAT5 promoter is active in the outer integument. Together, the Arabidopsis data indicated that there is a suberized layer associated with the outer integument and a cutin-like polyester layer associated with the inner seed coat.