Noninvasive Expressions of ipt in Whole Plants or Roots through pOp/LhG4 Indicate a Role of Plant Aerial Parts and Light in Cytokinin Synthesis and Root Inhibition

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• 作者：Jianchun Guo and Xinwen Hu
• 关键词：Noninvasive expression ; Cytokinin synthesis ; Constitutive expression ; Root ; specific expression ; ipt Gene ; pOp/LhG4
• 刊名：Journal of Plant Growth Regulation
• 出版年：2008
• 出版时间：September, 2008
• 年：2008
• 卷：27
• 期：3
• 页码：251-262
• 全文大小：481.9 KB

文摘

To study plant roots in response to ipt gene activation, the transcriptional fusions of ipt-GUS and GUS-ipt were expressed in roots or in whole plants of Arabidopsis under the control of a root-specific promoter TobRT7 or a CaMV35S promoter through the pOp/LhG4 system in noninvasive conditions. The transgenic plants with constitutive expression of ipt-GUS or GUS-ipt showed 15–25-fold or 1–2-fold increased cytokinin levels, respectively. ipt-GUS-expressing Arabidopsis had severe root inhibition, enlarged shoot apical parts, serrated leaves, and no or few sterile flowers, whereas GUS-ipt-expressing Arabidopsis grew faster, flowered early, and had more lateral shoots. However, when ipt-GUS and GUS-ipt were specially expressed in roots under the control of TobRT7, neither cytokinin content in roots or shoots nor phenotypes were altered. In cytokinin-overproducing, ipt-GUS-expressing Arabidopsis, the light and aerial parts of plants played an important role for cytokinin synthesis and root inhibition, and the ipt gene was vigorously expressed at the shoot apical parts. Meanwhile, calli were induced at the shoot apical parts of some cytokinin-overproducing, ipt-GUS-expressing Arabidopsis.