Abstract:

The ast (anthocyanin spotted testa) mutant, which was induced by carbon ion radiation, was a single recessive gene mutant of Arabidopsis thaliana (L.) Heynh. With spotted pigment in seed coats, and involved in the anthocyanin biosynthesis. To clone the AST gene by map_based cloning strategy, a series of molecular markers were designed according to the SNPs (single nucleotide polymophisms) and insertion/deletion polymophisms in the Arabidopsis database. With these molecular markers, the fine_structure mapping of the AST gene was finished, the AST locus was located in BAC clone T13M11. It was suggested that the AST candidate gene was T13M11.8 in the T13M11. This gene was 1 432 bp long with 6 exons and 5 introns. The putative protein of T13M11.8 gene was similar to dihydroflavonol 4_reductase (DFR), which was an important enzyme in the anthocyanin biosynthesis pathway.

拟南芥AST基因的精细作图
毛爱军 王台 宋艳茹
（中国科学院植物研究所资源植物分子与发育生物学研究中心，北京100093）

摘要： 拟南芥(Arabidopsis thaliana （L.）Heynh.）ast（anthocyanin spotted testa）突变体是由碳离子辐射诱导产生的与花青苷生物合成有关的基因突变体，受单隐性核基因控制。根据拟南芥数据库中的SNPs(single nucleotide polymophisms)序列和插入/缺失多态性（insertion/deletion polymorphisms）序列，设计了一系列分子标记。采用图位克隆策略，应用这些分子标记完成了对拟南芥AST基因的精细作图，成功地将AST基因定位到BAC克隆T13M11 上，初步认为该BAC 克隆中的基因T13M11.8 可能是AST 基因。该基因的DNA 序列长1432hp，含有6 个外显子和5 个内含子，编码的蛋白与花青苷生物合成途径中的二氢黄酮醇-4-还原酶有较高的同源性。将进一步通过功能互补实验验证图位克隆的结果。

关键词： ast 突变AST 基因；分子标记；精细作图；图位克隆；拟南芥
* 通讯作者。E-mail: twang@ns.ibcas.ac.cn.