2011年12月02日，河北师范大学尚忠林、郝立华、王伟霞、陈忱利用NMT在Molecular Plant 上发表了标题为Extracellular ATP promotes stomatal opening of Arabidopsis thaliana through heterotrimeric G protein a subunit and reactive oxygen species的研究成果。
- 期刊：Molecular Plant
- 标题：Extracellular ATP promotes stomatal opening of Arabidopsis thaliana through heterotrimeric G protein a subunit and reactive oxygen species
In recent years, adenosine tri-phosphate (ATP) has been reported to exist in apoplasts of plant cells as a signal molecule. Extracellular ATP (eATP) plays important roles in plant growth, development, and stress tolerance.
Here, extracellular ATP was found to promote stomatal opening of Arabidopsis thaliana in light and darkness. ADP, GTP, and weakly hydrolyzable ATP analogs (ATPγS, Bz-ATP, and 2meATP) showed similar effects, whereas AMP and adenosine did not affect stomatal movement. Apyrase inhibited stomatal opening. ATP-promoted stomatal opening was blocked by an NADPH oxidase inhibitor (diphenylene iodonium) or deoxidizer (dithiothreitol), and was impaired in null mutant of NADPH oxidase (atrbohD/F).
Added ATP triggered ROS generation in guard cells via NADPH oxidase. ATP also induced Ca2+ influx and H+ efflux in guard cells. In atrbohD/F, ATP-induced ion flux was strongly suppressed. In null mutants of the heterotrimeric G protein α subunit, ATP-promoted stomatal opening, cytoplasmic ROS generation, Ca2+ influx, and H+ efflux were all suppressed.
These results indicated that eATP-promoted stomatal opening possibly involves the heterotrimeric G protein, ROS, cytosolic Ca2+, and plasma membrane H+-ATPase.
在这里，发现细胞外ATP在光与暗中促进拟南芥气孔的开放。ADP，GTP和弱水解性ATP类似物（ATPγS，Bz-ATP和2meATP）显示出相似的作用，而AMP和腺苷并不影响气孔运动。磷酸酶抑制气孔开放。ATP促进的气孔开放被NADPH氧化酶抑制剂（二亚苯基碘鎓）或脱氧剂（二硫苏糖醇）阻止，并且在NADPH氧化酶的无效突变体（atrbohD / F）中受损。
添加的ATP通过NADPH氧化酶触发了保卫细胞中ROS的生成。ATP还诱导了保卫细胞中Ca2 +的流入和H +的流出。在atrbohD / F中，ATP诱导的离子通量被强烈抑制。在异源三聚体G蛋白α亚基的无效突变体中，ATP促进的气孔开放，细胞质ROS生成，Ca2+涌入和H+外排均被抑制。
Figure 6ATP Stimulates Ca2+ Influx and H+Efflux in Guard Cells of Arabidopsis thaliana (Ecotype col-0).
(A) Gadolinium chloride (50 μM) blocked ATP-promoted stomatal opening.
(B) and (C) show time course of Ca2+ flux in MES buffer without (B) or with (C) epidermis before and after 0.6 mM ATP treatment, respectively. The arrow marks time points of ATP treatment.
(D) The dose-dependence of ATP-promoted Ca2+ influx; data are the means ± SE (n = 30) of the peak Ca2+ influx value after ATP stimulation. The positive and negative values of ion flux represent ion influx and efflux, respectively.
(E) Sodium vanadate (100 μM) blocked ATP-promoted stomatal opening.
(F) and (G) show time courses of H+ flux in MES buffer without (F) or with (G) epidermis before and after 0.6 mM ATP treatment, respectively.
The arrow marks time points of ATP treatment. In (A) and (E), data are means ± SE (n = 6) for stomatal aperture. In all figures, ‘control’ means treatment with MES buffer only. (H) The dose-dependence of ATP-promoted H+ influx; data are the means ± SE (n = 30) of the peak H+ efflux value after ATP stimulation.