Transposition and gene regulation of DNA transposable elements in plants

高等植物主要的转座调控元件可分为Ac/Ds （hAT）超家族、En/Spm （CACTA）超家族和Mu家族。作为花卉植物，常见的牵牛花（I. purpurea）的自发突变体显示白色或红色的花朵，而日本牵牛花（I. nil）的各种自发突变体显示许多不同的花朵颜色。我们正试图识别这些自发突变，包括赋予杂色花的可变等位基因。此外，我们还尝试了在水稻中进行同源重组的基因靶向。突变的斑点、斑点、r-1和紫色等位基因是由Tpn1及其En/Spm超家族的近缘基因Tpn2、Tpn3和Tpn4插入到植物花青素着色基因（即DFR-B）中引起的。CHI, CHS-D, InNHX1。同样，紫花紫豆的片状突变体和粉红色突变体在Ac/Ds超家族中分别有插入CHS-D和F3'H基因的远亲元件tip100和Tip201。水稻是一种重要的主食，也是其他谷类物种的模式植物，我们开发了一种大规模的农杆菌介导的转化程序，具有强的正负选择，并通过同源重组成功地靶向了Waxy基因，而没有伴随不良异位事件的发生。

The major DNA-based controlling transposable elements in higher plants can be classified into three groups : the Ac/Ds (or hAT) superfamily, the En/Spm (or CACTA) superfamily, and the Mu family. As floricultural plants, spontaneous mutants of the common morning glory (I. purpurea) displaying either white or reddish flowers were obtained while various spontaneous mutants of the Japanese morning glory (I. nil) exhibiting many different flower colorations were generated. We are trying to identify these spontaneous mutants including mutable alleles conferring variegated flowers. In addition, we also attempted gene targeting by homologous recombination in rice.The mutable flecked, speckled, r-1, and purple alleles in I. nil were caused by insertions of Tpn1 and its relatives in the En/Spm superfamily, Tpn2, Tpn3, and Tpn4, into the genes for anthocyanin coloration in wers, i.e., DFR-B. CHI, CHS-D, and InNHX1, respectively. Similarly, the flaked and pink mutants of I. purpurea have distantly related elements, Tip1OO and Tip201, in the Ac/Ds superfamily inserted into the CHS-D and F3'H genes, respectively. Concerning gene targeting in rice, an important staple food and a model plant for other cereal species, we have developed a large-scale Agrobacterium-mediated transformation procedure with a strong positive-negative selection and succeeded a reproducible targeting of the Waxy gene by homologous recombination without concomitant occurrence of undesirable ectopic events.