Overexpression of Rice OSH Genes Induces Ectopic Shoots on Leaf Sheaths of Transgenic Rice Plants

Naoki Sentoku, Yutaka Sato, Makoto Matsuoka
Developmental Biology, 2000, 220(2): 358-364     追溯原文......本站官方QQ群:62473826
homeobox gene; transgenic rice; ectopic shoot; leaf

Five rice homeobox (OSH) genes were overexpressed under the control of the cauliflower mosaic virus 35S promoter or the rice actin gene promoter in transgenic rice plants. Almost all of the transgenic plants showed abnormal phenotypes, which could be classified into three types according to their severity. Plants with the most severe phenotype formed only green organs, with many shoot apices on their adaxial sides. Plants with an intermediate phenotype formed bladeless leaves with normally developed leaf sheaths. Plants with a mild phenotype formed normal leaf sheaths and blades, but lacked ligules and showed diffusion of the blade–sheath boundary. The leaf structure of this phenotype was similar to that of dominant maize mutants, such as Kn1, Rs1, Lg3, and Lg4. Based on these phenotypes, we suggest that ectopic expression of the rice OSH genes interferes with the development of leaf blades and maintains leaves in less differentiated states. These results are discussed in relation to the leaf maturation schedule hypothesis (M. Freeling et al., 1992, BioEssays 14, 227–236).

水稻OSH基因过表达能诱导转基因水稻的叶鞘产生异位芽

5个水稻OSH基因OSH1,OSH15、OSH71、OSH6、OSH43分别加上启动子35S和acin启动构成过表达载体转入水稻植株中表达。几乎所用的转基因植株表现出不正常表型,根据它们的严重程度分为3类。严重表型的植株只产生绿色的器官,在其近轴面有许多芽。中间表型的植株不能形成叶片,但叶鞘正常。轻度的植株能有正常的叶及叶鞘,但没有叶舌,叶与叶鞘的边界弥散。该表型的叶组织结构类似于显性的玉米突变体,如KN1、Rs1、Lg3和Lg4。基于这些表型,我们认为水稻OSH1基因的异位表达干扰了叶片的发育和促使叶处于未分化的状态。我们也将这些结果与叶成熟时间表假说之间的关系进行讨论。


基因列表
  矮秆基因;水稻同源异型盒基因 d6; OSH15;Oskn3
  水稻同源异型盒基因 OSH6
  同源异型盒基因 OSH1; Oskn1
  同源异型盒基因 OSH71; Oskn2
  水稻同源异型盒基因 OSH43