Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, P.O. Box 15005, Porto Alegre, RS, 91501-970, Brazil.
Mol Biol Rep. 2010 Dec;37(8):3735-45. doi: 10.1007/s11033-010-0027-0. Epub 2010 Mar 10.
Fe participates in several important reactions in plant metabolism. However, Fe homeostasis in plants is not completely understood, and molecular studies on Fe-excess stress are scarce. Rice (Oryza sativa L. ssp. indica) is largely cultivated in submerged conditions, where the extremely reductive environment can lead to severe Fe overload. In this work, we used representational difference analysis (RDA) to isolate sequences up-regulated in rice shoots after exposure to Fe-excess. We isolated 24 sequences which have putative functions in distinct cellular processes, such as transcription regulation (OsWRKY80), stress response (OsGAP1, DEAD-BOX RNA helicase), proteolysis (oryzain-α, rhomboid protein), photosynthesis (chlorophyll a/b binding protein), sugar metabolism (β glucosidase) and electron transport (NADH ubiquinone oxireductase). We show that the putative WRKY transcription factor OsWRKY80 is up-regulated in rice leaves, stems and roots after Fe-excess treatment. This up-regulation is also observed after dark-induced senescence and drought stress, indicating that OsWRKY80 could be a general stress-responsive gene. To our knowledge, this is the first report of an Fe-excess-induced transcription factor in plants.
铁参与植物代谢中的几个重要反应。然而，植物中铁的动态平衡还不完全清楚，铁过量应激的分子研究也很少。水稻（Oryza sativa L. ssp. indica）主要在淹水条件下种植，在这种极其还原的环境中，铁可能会严重过载。在这项工作中，我们使用代表性差异分析（RDA）来分离暴露于铁过量后水稻芽中上调的序列。我们分离出了 24 个序列，它们在不同的细胞过程中具有潜在的功能，如转录调节（OsWRKY80）、应激反应（OsGAP1、DEAD-BOX RNA 解旋酶）、蛋白水解（oryzain-α、菱形蛋白）、光合作用（叶绿素 a/b 结合蛋白）、糖代谢（β 葡萄糖苷酶）和电子传递（NADH 泛醌氧化还原酶）。我们表明，铁过量处理后，水稻叶片、茎和根中的假定 WRKY 转录因子 OsWRKY80 上调。这种上调也发生在黑暗诱导的衰老和干旱胁迫后，表明 OsWRKY80 可能是一个普遍的应激反应基因。据我们所知，这是植物中铁过量诱导的转录因子的首次报道。
