不同倍性水稻胚乳蛋白的差异表达研究

Differential expression of the proteins in endosperms of rice with different chromosome sets

以4份同源四倍体水稻和4份相应的二倍体水稻为研究材料,对其种子内清、球蛋白(清蛋白和球蛋白)、醇溶蛋白和谷蛋白的含量进行了测定,利用聚丙烯酰胺凝胶电泳(SDS-PAGE)技术分析了其特异性。结果表明:同源四倍体水稻胚乳蛋白各组分含量与相应的二倍体相比,大部分呈增加趋势;同源四倍体水稻胚乳蛋白的亚基类型与相应的二倍体水稻基本一致,仅在全蛋白电泳和清、球蛋白电泳中各发现1条差异条带。研究结果认为:二倍体水稻经过染色体组加倍之后,同源四倍体水稻重复基因组在蛋白质水平上的表达结果趋于“二倍化”,即与二倍体水稻表现出相似的特点,但在蛋白质表达量上前者往往高于后者。基因组多倍化对同源四倍体水稻重复基因组进化最主要的影响并不是体现在蛋白质结构上的差异,而是体现在蛋白质表达量上的差异。

The present paper compared the major storage proteins in starchy endosperm of four autotetraploid rice lines with that of their corresponding diploid rice lines. The content of albumin, globulin, prolamin and glutelin in each sample was determined respectively. The structure and expression pattern of each storage protein was investigated using one-dimensional SDS-PAGE. Our results showed that the protein content of each fraction in endosperm of autotetraploid rice line is mostly higher than that of its corresponding diploid rice line. However, the SDS-PAGE analysis showed that the subunit types of each storage protein of autotetraploid rice line was generally homologous to that of its corresponding diploid rice line, except for one differential band observed on SDS-PAGE gels of total protein fraction and another on the SDS-PAGE gels of albumin and globulin fraction. These results indicated that duplicated genes in autotetraploid rice acquired the same expression patterns as that seen in its corresponding diploid rice. It was suggested that the doubling of chromosome sets did not change the protein expression profile but the protein expression level in the starchy endosperm of autotetraploid rice.