甘蓝型油菜种子中油体的超微结构及蛋白质组分析

以甘蓝型油菜（Brassica napus L.）含油量较高的品种‘ZS11’、含油量中等的品种‘Westar’和‘Topas’以及含油量较低的品种‘ZS10’为实验材料，通过超微结构观察和统计，比较分析不同品种种子中油体形态、大小和数量的差异。研究结果显示，品种‘ZS11’种子子叶细胞油体排列致密，形态较小，大部分油体的直径低于1 μm；而在含油量中等或较低的品种中，种子子叶细胞油体排列均显疏松，其中‘Westar’和‘Topas’的油体较大，而‘ZS10’的油体大小不一。本研究还通过双向电泳分析进一步检测了‘Westar’和‘ZS11’种子中总蛋白和油体蛋白的差异表达情况。结果显示，‘Westar’和‘ZS11’种子总蛋白双向电泳图谱中，表达量具有2倍以上差异的蛋白质点共有57个；其中在‘Westar’中特异表达的种子总蛋白质点有24个，在‘ZS11’中有23个。在上述2个品种油体蛋白双向电泳图谱中，表达量具有2倍以上差异的蛋白质点共有52个，在品种‘Westar’中特异表达的有2个，‘ZS11’中有13个。表明不同含油量的油菜品种种子在油体的结构和蛋白组份上均存在差异。

Study on the ultrastructure and proteome of oil bodies in Brassica napus L.seeds

Rapeseed is one of the most important oil crops in China.The oil content of seeds is directly related to the national economy and people's livelihood.Fatty acids in rapeseeds are stored in the form of oil bodies composed of triacylglycerol (TAG) molecules,which are made of three fatty acid chains joined covalently to a glycerol molecule.We analyzed the ultrastructural characteristics of oil bodies in the seeds of four cultivars that contained varied oil content,including high oil content ‘ZS11’,medium oil content ‘Westar’ and ‘Topas’,and low oil content ‘ZS10’.Results showed that the size and density of the oil bodies in the four cultivars were varied.In the seeds of ‘ZS11’,the density of the oil bodies was higher but the size of the oil bodies was smaller (less than 1 μm in diameter).Interestingly,the density of the oil bodies in the seeds of the medium and low oil content cultivars was lower.Larger sized oil bodies were found in the seeds of the medium oil cultivars,but oil body size in the seeds of the low oil cultivar was diverse.Because oil-body protein composition is related to oil body size and oil content of seeds,total and oil-body protein profiles in the seeds of ‘ZS11’ and ‘Westar’ were explored by two-dimensional electrophoresis.Compared with the total protein profiles,57 differentially expressed proteins were detected in the seeds of both ‘Westar’ and ‘ZS11’ cultivars,indicating at least a two-fold difference in expression levels;in addition,24 and 23 proteins were specifically expressed in ‘Westar’ and ‘ZS11’ seeds,respectively.Compared with the oil-body protein profiles,we observed 52 differentially expressed proteins in the oil bodies of both cultivars,indicating at least a two-fold difference in expression levels;furthermore,we detected 2 and 13 proteins specifically expressed in oil-body proteins of ‘Westar’ and ‘ZS11’ seeds,respectively.Our findings indicate that the ultrastructure and protein composition of the oil bodies differed in different rapeseed cultivars.