RED-LIGHT STIMULATES AN ELECTROGENIC PROTON PUMP IN VICIA GUARD-CELL PROTOPLASTS
RED-LIGHT STIMULATES AN ELECTROGENIC PROTON PUMP IN VICIA GUARD-CELL PROTOPLASTS
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DOI：
10.1073/pnas.85.2.436
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发表时间：
1988-01-01
影响因子：
11.1
通讯作者：
HAGIWARA, S
中科院分区：
文献类型：
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作者：
SERRANO, EE;ZEIGER, E;HAGIWARA, S
气孔开张对光的反应具有与叶绿素吸收光谱相匹配的成分；然而，介入的感觉转导步骤并不是很好地被理解。为了研究这一过程，我们用红光照射蚕豆保卫细胞原生质体，同时利用全细胞构型的膜片钳技术记录流过质膜的电流。我们报告有证据表明，在电压钳位条件下，红光(1 mmos光子.cntdo.M-2.cntdo.S-1)激发了一种外向电流。这种反应需要在细胞膜的细胞质一侧加入ATP(2.5 mM)和正磷酸盐(1 MM)。红光刺激电流和由质子泵激动剂褐霉素(10微米)在黑暗中激活的电流都被10微米的质子团羰基氰化物间氯苯肼消除，表明这些反应是由质子携带的。泵电流被施加到细胞质一侧的原钒酸抑制(在3.5µm时抑制50%)，这意味着H+-ATPase。在饱和浓度的ATP存在下，光合作用抑制剂3-(3，4-二氯苯基)-1，1-二甲基脲消除电流，表明需要具有光合作用活性的叶绿体。我们的结论是，红光刺激了Vicia保卫细胞质膜上的一个生电质子泵，叶绿体调节了这一反应。
Stomatal opening in response to light has a component that matches the absorption spectrum of chlorophyll; however, the intervening sensory transduction steps are not well understood. To study this process, we illuminated Vicia faba guard cell protoplasts with red light and simultaneously recorded current flow across the plasma membrane, utilizing the patch clamp technique in the whole cell configuration. We report evidence that under voltage clamp conditions, red light (1 mmol of photons .cntdot. m-2 .cntdot. s-1) stimulated an outward current. This response required ATP (2.5 mM) and orthophosphate (1 mM) at the cytoplasmic side of the membrane. Both red-light-stimulated currents and currents activated in the dark by the proton pump agonist fusicoccin (10 .mu.M) were abolished by the protonophore carbonylcyanide m-chlorophenylhydrazone at 10 .mu.M, indicating that these responses were carried by protons. Pump currents were inhibited by orthovanadate applied to the cytoplasmic side of the membrane (50% inhibition at 3.5 .mu.M), implicating a H+-ATPase. Elimination of the current by the photosynthetic inhibitor 3-(3,4-diclorophenyl)-1,1-dimenthylurea, in the presence of saturating concentrations of ATP, pointed to a requirement for photosynthetically active chloroplasts. We conclude that red light stimulates an electrogenic proton pump at the plasmalemma of Vicia guard cells and that chloroplasts modulate this response.