A Patch-Clamp Investigation of the Role of the Phosphatidyl-inositol Pathway in Mediating Plant Cell Responses to Blue Light

使用电生理学（膜片钳）技术， 研究人员发现，蓝光激活了一种 保护细胞膜上的超极化质子泵。 超极化产生钾离子流入的梯度， 推测是通过钾特异性离子通道发生的， 导致吸水、细胞膨胀和气孔打开。 拟议研究的目标是调查 蓝光激活质子泵和/或 钾通道开放的调节是由 磷脂酰肌醇（PI）途径。 初步实验 表示PI组分二酰基甘油的类似物 途径，可以增强光刺激的气孔开放， 表皮脱落 膜片钳将用于确定 这些和PI的其他生化调节剂的作用 蓝光激发离子泵和钾离子通道 保卫细胞原生质体的通道动力学。 的 保卫细胞对蓝光的电生理反应 拟南芥突变体（phi 3-4）也将被 表征了 该突变体缺乏向光性反应，并且 在蓝光照射下也表现出减少的气孔开放。 蓝光在植物中介导各种反应，例如 气孔开放，允许气体和水分交换， 向光弯曲和叶绿体发育。 拟议 研究将集中在气孔的反应，并将有助于 更清楚地了解细胞机制， 植物对蓝光有感应和反应。

Using electrophysiological (patch clamping) techniques, this investigator has shown that blue light activates a hyperpolarizing proton pump at the guard cell membrane. Hyperpolarization creates a gradient for potassium influx, presumed to occur through potassium-specific ion channels, resulting in water uptake, cell swelling, and stomatal opening. The goals of the proposed research are to investigate the possibility that blue-light-activation of the proton pump and/or regulation of potassium channel opening is mediated by the phosphatidylinositol (PI) pathway. Preliminary experiments indicate that analogs of diacylglycerol, a component of the PI pathway, can enhance light-stimulated opening of stomata in epidermal peels. Patch clamping will be used to determine the effects of these and other biochemical regulators of the PI pathway on blue-light-stimulated ion pumping and potassium channel kinetics of guard cell protoplasts. The electrophysiological response to blue light of guard cells from an Arabidopsis thaliana mutant (phi 3-4) will also be characterized. This mutant lacks a phototropic response, and also exhibits reduced stomatal opening under blue illumination. Blue light mediates a variety of responses in plants, such as opening of stomatal pores to allow gas and water exchange, bending toward light, and chloroplast development. The proposed research will focus on the stomatal response and will contribute to a clearer understanding of the cellular mechanisms by which plants detect and respond to blue light.