Molecular analysis of two ethylene-induced cell death processes in rice (Oryza sativa L.)

细胞死亡是植物发育的固有部分。它可以是发育调节的，也可以由环境信号诱导。被洪水淹没的植物遭受缺氧之苦。为了避免低氧胁迫，适应良好的植物，如水稻，通过在茎上生长根和通过形成内部空气空间(通风组织)来改善它们的氧气供应。在根生长之前，覆盖根原基的表皮细胞死亡。表皮细胞死亡和通风组织的形成受植物激素乙烯的调节。我们以前发现了细胞死亡的表皮细胞和没有死亡的表皮细胞之间的形态和分子差异。在目前的项目中，我们试图定义表皮细胞死亡的细胞特征和信号通路。我们将从功能上描述在死亡细胞和非死亡细胞中发现的差异活性基因，重点放在决定细胞特性的基因上。这些基因可能与细胞死亡的能力和细胞死亡的局部限制有关。在突变体的帮助下，被认为对表皮细胞死亡起重要作用的基因将在通风组织形成中进行研究，这代表了乙烯诱导的第二个局部细胞死亡过程。这项研究的比较部分应该有助于确定乙烯导致细胞死亡的信号传递和执行过程中的共同和不同途径。

Cell death is an intrinsic part of plant development. It can be developmentally regulated or be induced by environmental signals. Flooded plants suffer from lack of oxygen. To avoid hypoxic stress, well adapted plants such as rice improve their oxygen supply through growth of roots at the stem and through formation of internal air spaces (aerenchyma). Growth of roots is preceded by death of epidermal cells that cover the root primordia. Epidermal cell death as well as aerenchyma formation are regulated by the plant hormone ethylene. We previously identified morphological and molecular differences between epidermal cells that undergo cell death and those that do not. In the current project we attempt to define the cellular characteristics and the signaling pathway of epidermal cell death. We will functionally characterize genes that were found to be differentially active in dying versus non-dying cells with a focus on genes which determine cell identity. Such genes may be responsible for the ability to undergo cell death and for the local confinement of cell death. With the help of mutants, genes that have been recognized as being important for epidermal cell death will be studied in aerenchyma formation, which represents a second ethylene-induced local cell death process. This comparative part of the study should help pinpoint common and diverging pathways in the signaling and execution of cell death by ethylene.