Studies on Pi homeostasis by artificial manipulation of intracellular Pi levels.

通过人工调控细胞内 Pi 水平来研究 Pi 稳态。

• 批准号: 07640856
• 负责人: MIMURA Tetsuro
• 金额: $ 1.66万
• 依托单位: HITOTSUBASHI UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07640856/
• 关键词: Barlcy; Cell membrane; Characeae; Inorganic phosphate; Ion homeostasis; Phosphate transport; Plant nutrition; Vacuole; 細胞内pH; 植物培養細胞

Inorganic phosphate is one of the essential molecules for plant growth. In natural environment, however, Pi level in soil is extremely low. Even under Pi deficiency, it is well-known that the cytoplasmic Pi level was kept at constant by changing Pi transport activities across the membrane, although the vacuolar Pi level changed related to Pi supply. We call it is Pi homeostasis in plants. However, we have no information, yet how the plant cell detects changes in Pi supply and controls Pi status in the cell. Until now, most of works on the cellular Pi transport mechanisms related to Pi supply were carried out using growing plants or proliferating cultured cells as experimental materials. In these situation, since the cellular physiological status is always changing, it is difficult to analyze Pi homeostatic mechanisms only. In the present study, we tried to control Pi situation independent of cell growth.First we measured the Pi distribution of barley plants under different Pi situation in order to know the usual experimental conditions. Then we used an isolated and matured Chara internodal cells as material. They do not grow, divide and of course differentiate. Using such cells, we have found first that the removal of Pi from the vacuole by perfusion could not induce any changes in Pi transport activity of the tonoplast. Furthermore, we found that the Pi uptake activity of the plasma membrane also changes independent of both the cytoplasmic and the vacuolar Pi pools.Besides above, we found that the acid treatment of suspension cultured Catharanthus cells induced changes in the Pi metabolisms. We are now analyzing the relationship of all these phenomena.

无机磷酸盐是植物生长必需的分子之一。然而，在自然环境中，土壤中的Pi含量极低。即使在 Pi 缺乏的情况下，众所周知，尽管液泡 Pi 水平的变化与 Pi 的供应有关，但通过改变 Pi 跨膜转运活动，细胞质 Pi 水平仍保持恒定。我们称之为植物中的 Pi 稳态。然而，我们还没有了解植物细胞如何检测 Pi 供应的变化并控制细胞中 Pi 的状态。迄今为止，大多数与Pi供应相关的细胞Pi运输机制的工作都是使用生长的植物或增殖的培养细胞作为实验材料进行的。在这种情况下，由于细胞的生理状态总是在变化，因此很难仅分析Pi稳态机制。在本研究中，我们试图控制独立于细胞生长的Pi情况。首先，我们测量了大麦植株在不同Pi情况下的Pi分布，以了解通常的实验条件。然后我们以分离成熟的轮藻节间细胞为材料。它们不会生长、分裂，当然也不会分化。使用此类细胞，我们首先发现通过灌注从液泡中去除 Pi 不会引起液泡膜 Pi 转运活性的任何变化。此外，我们发现质膜的Pi吸收活性也独立于细胞质和液泡Pi池而变化。除此之外，我们发现悬浮培养的长春花细胞的酸处理诱导了Pi代谢的变化。我们现在正在分析所有这些现象之间的关系。

项目成果

Beilby M.J.: "Perfusion of charophyte cells : A critical analysis of the method." J.Experimental Botany. (in press).

Beilby M.J.：“轮藻细胞的灌注：对该方法的批判性分析。”

Beilby M.J.: "Perfusion of charophyte cells : A critical analysis of the method." J. Experimental Botany. (in press).

Beilby M.J.：“轮藻细胞的灌注：对该方法的批判性分析。”

Mimura T.: "Physiological characteristic and regulaion mechanisms of the H^+ pumps in the plasma membrane and tonoplast of Characean cells." Journal of Plant Research. 108. 249-256 (1995)

Mimura T.：“Characean细胞质膜和液泡膜中H^泵的生理特征和调节机制。”

Sakano K.: "Lack of control in inorganic phosphate uptake by Catharanthus roseus (L.) G. Don cells." Plant Physiology. 108. 295-302 (1995)

Sakano K.：“长春花 (L.) G. Don 细胞对无机磷酸盐的吸收缺乏控制。”

Sakano K.: "Lack of control in inorganic phosphate uptake by Catharanthus roseus (L.) G.Don cells." Plant Physiology. 108. 295-302 (1995)

Sakano K.：“长春花 (L.) G.Don 细胞对无机磷酸盐的吸收缺乏控制。”