Signal Transduction Across Plant Plasma Membranes

该实验室先前的结果表明， 植物的防御反应与植物细胞上的受体结合 在0 - 8分钟内激发氢气爆发 过氧化物 这种过氧化氢的突然产生 只是为了破坏某些致病化合物， 刺激随后植物抗毒素产生。 下一个目标 这项研究是为了表征氧化爆发，确定 它在触发植物防御素生物合成中的作用，评估是否 其他防御化合物由氧化爆发诱导， 确定参与其合成的酶和底物。 最近的结果还表明，激发子分子是 通过内吞作用内在化， 植物细胞表面的受体。 在进一步的实验中， 检测受体内化的动力学， 当它从细胞表面移动到 最终的细胞内目的地。 受体是否 不同的诱导子遵循相同的途径也将是 评估。 最后，已经发现植物细胞具有 生物素受体和大分子可以被递送 通过生物素受体介导的内吞作用进入活的植物细胞 如果大分子首先被共价衍生化， 生物素。 使用这种途径来递送酶、核酸和蛋白质， 酸、毒素和抗体等进入活的植物细胞， 探讨了 就像高等动物有发达的免疫反应一样， 防御病原体，高等植物也有防御 使它们能够抵抗入侵和破坏。 的 调节植物防御反应的机制是一种 这是一个非常重要的基本问题，迄今为止， 是已知的。 在NSF的支持下，Low博士和Heinstein博士 发现大豆细胞暴露于一种化学物质中 （"激发器"）的防御反应是紧随其后， 植物细胞产生过氧化氢。 进一步 这项研究的目的是澄清氢的作用 过氧化氢在防御反应，并追求其他线索， 关于植物暴露于 一种潜在的病原体， 防护化学品。 该项目的成果应 有助于我们理解 调节植物防御反应的机制。

Prior results from this laboratory have shown that elicitors of a plant's defense response bind to receptors on the plant cell surface and within 0-8 minutes stimulate a burst of hydrogen peroxide. This sudden production of hydrogen peroxide serves not only to destroy certain pathogenic compounds but may also stiimulate subsequent phytoalexin production. The next goals of this research are to characterize the oxidative burst, determine its role in triggering phytoalexin biosynthesis, evaluate whether other defense compounds are induced by the oxidative burst, and identify the enzymes and substrates involved in its synthesis. Recent results also indicate that the elicitor molecule is internalized via endocytosis following association with its receptor on the plant cell surface. In further experiments, the kinetics of internalization of the receptor will be examined, and its path will be monitored as it moves from the cell surface to its final intracellular destination . Whether receptors for different elicitors follow identical pathways will also be evaluated. Finally, it has been found that plant cells have receptors for biotin and that macromolecules can be delivered into a living plant cell via biotin receptor-mediated endocytosis if the macromolecules are first covalently derivatized with biotin. The use of this pathway to deliver enzymes, nucleic acids, toxins and antibodies, etc into living plant cells will be explored. Just as higher animals have well developed immune responses to defend against pathogens, higher plants also have defense responses that allow them to resist invasion and damage. The mechanisms by which plant defense responses are regulated is a very important fundamental problem about which, thus far, little is known. With prior NSF support, Drs. Low and Heinstein discovered that exposure of soybean cells to a chemical trigger ("elicitor") of a defense response is followed very quickly by production of hydrogen peroxide by the plant cells. The further goals of this research are to clarify the role of hydrogen peroxide in the defense response, and to pursue other leads concerning the sequence of events between exposure of a plant to a potential pathogen and the production by the plant of protective chemicals. The results of this project should contribute to our understanding of the cellular signaling mechanisms that regulate plant defense responses.