Transposition and gene regulation of DNA transposable elements in plants

高等植物中主要的DNA控制转座元件可分为三大类：Ac/DS(或HAT)超家族、EN/SPM(或CACTA)超家族和Mu家族。作为花卉栽培植物，获得了表现白色或红色花的普通牵牛花(I.Purpurea)的自发突变体，以及表现多种不同花色的日本牵牛花(I.nil)的各种自发突变体。我们正试图鉴定这些自发的突变体，包括与杂色花有关的可变等位基因。此外，我们还尝试了在水稻中利用同源重组的方法进行基因打靶。其中，突变的斑点、斑点、r-1和紫色等位基因是通过将EN/SPM超家族中的Tpn1及其近亲Tpn2、Tpn3和Tpn4插入到Wers的花青素着色基因Dfr-B中而导致的。CHI、CHS-D和InNHX1。类似地，紫斑盘藻的片状突变体和粉红色突变体分别含有Ac/DS超家族中的远亲元件Tip100和Tip201，分别插入CHS-D和F3‘H基因。水稻是一种重要的粮食作物，也是其他粮食作物的模式植物。在水稻基因打靶方面，我们发展了一种具有强正反选择的大规模农杆菌介导的转化程序，并通过同源重组成功地实现了蜡质基因的重复性打靶，且没有发生不希望发生的异位现象。

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.