Department of Botany and Plant Sciences and the Center for Plant Cell Biology, University of California, Riverside, CA 92521, USA; Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
Department of Biology, Indiana University, Bloomington, IN 47405-3700, USA; Department of Natural Science, Dickinson State University, Dickinson, ND 58601, USA.
Plant Physiol Biochem. 2014 Oct;83:185-93. doi: 10.1016/j.plaphy.2014.07.014. Epub 2014 Aug 1.
The plant hormone abscisic acid (ABA) controls many aspects of plant growth and development, including seed development, germination and responses to water-deficit stress. A complex ABA signaling network integrates environmental signals including water availability and light intensity and quality to fine-tune the response to a changing environment. To further define the regulatory pathways that control water-deficit and ABA responses, we carried out a gene-trap tagging screen for water-deficit-regulated genes in Arabidopsis thaliana. This screen identified PLASTID MOVEMENT IMPAIRED1 (PMI1), a gene involved in blue-light-induced chloroplast movement, as functioning in ABA-response pathways. We provide evidence that PMI1 is involved in the regulation of seed germination by ABA, acting upstream of the intersection between ABA and low-glucose signaling pathways. Furthermore, PMI1 participates in the regulation of ABA accumulation during periods of water deficit at the seedling stage. The combined phenotypes of pmi1 mutants in chloroplast movement and ABA responses indicate that ABA signaling may modulate chloroplast motility. This result was further supported by the detection of altered chloroplast movements in the ABA mutants aba1-6, aba2-1 and abi1-1.
植物激素脱落酸（ABA）控制着植物生长和发育的许多方面，包括种子发育、萌发以及对水分亏缺胁迫的响应。一个复杂的 ABA 信号网络整合了环境信号，包括水分可用性和光强和质量，以微调对不断变化的环境的响应。为了进一步定义控制水分亏缺和 ABA 响应的调节途径，我们在拟南芥中进行了一个基因捕获标记筛选，以寻找水分亏缺调节基因。该筛选鉴定了参与蓝光诱导的叶绿体运动的 PLASID MOTION IMPAIRED1（PMI1）作为 ABA 响应途径中的一个功能基因。我们提供的证据表明，PMI1 参与 ABA 调控种子萌发，作用于 ABA 和低葡萄糖信号通路交叉点的上游。此外，PMI1 参与幼苗期水分亏缺期间 ABA 积累的调节。pmi1 突变体在叶绿体运动和 ABA 响应方面的综合表型表明，ABA 信号可能调节叶绿体的运动性。ABA 突变体 aba1-6、aba2-1 和 abi1-1 中检测到的叶绿体运动改变进一步支持了这一结果。
