| 摘要: |
| 【目的】了解植物鞘氨醇-1-磷酸（Phyto-S1P）在暗诱导蚕豆气孔关闭中的作用及信号转导过程，为进一步阐明暗调控植物气孔运动的信号转导机制提供依据。【方法】以蚕豆（Vicia faba）为材料，借助药理学试验，基于一氧化氮（NO）特异荧光探针（DAF-2 DA）和pH特异荧光探针（BCECF-AM）的激光共聚焦显微技术，通过测定气孔开度和保卫细胞NO和pH水平的变化，确定Phyto-S1P在暗诱导蚕豆气孔关闭中的作用机制。【结果】暗处理能显著诱导蚕豆气孔关闭且可引起NO水平升高，这种效应可被长链碱基激酶抑制剂DL-threo-二氢鞘氨醇（DL-threo-DHS）和-N，N-二甲基鞘氨醇（DMS）显著抑制；外源Phyto-S1P可明显诱导蚕豆气孔关闭，且可以提高NO水平，但NO特异清除剂cPTIO和NOS抑制剂L-NAME可明显抑制Phyto-S1P的这些效应，表明Phyto-S1P通过诱导NO的产生介导暗诱导气孔关闭。此外，暗诱导胞质pH升高和气孔关闭可被DL-threo-DHS和DMS显著抑制，外源Phyto-S1P可以明显诱导胞质pH升高和气孔关闭，且Phyto-S1P的这种效应可被丁酸显著抑制，该结果提示Phyto-S1P通过诱导胞质碱化参与暗诱导气孔关闭。外源Phyto-S1P处理引起的保卫细胞胞质pH升高较NO水平升高滞后期短，达到峰值更早，且Phyto-S1P引起的NO水平升高可被丁酸显著抑制，这进一步证实Phyto-S1P诱导保卫细胞胞质碱化是NO产生的先决条件。【结论】Phyto-S1P通过诱导保卫细胞胞质碱化和NO产生介导暗诱导蚕豆气孔关闭，胞质碱化是NO产生的诱导因素。 |
| 关键词: 植物鞘氨醇-1-磷酸 胞质pH 一氧化氮 暗诱导 气孔关闭 蚕豆 |
| DOI： |
| 分类号: |
| 基金项目:山西省高等学校大学生创新创业训练项目（2013142）；山西师范大学自然科学基金课题（ZR09016）；山西师范大学生命科学学院院基金课题（SMYKZ-22） |
|
| Effect of Phytosphingosine-1-phosphate on darkness-induced stomatal closure and levels of pH and NO in Vicia faba guard cells |
|
MA Yin-li,SHE Xiao-ping,YAN Yue
|
| Abstract: |
| 【Objective】The role of phytosphingosine-1-phosphate (Phyto-S1P) in darkness-induced Vicia faba stomatal closure and the signal transduction were analyzed to improve further elucidation of signaling transduction in darkness-mediated stomatal movement of plants.【Method】Using pharmacological analysis,and NO-specific fluorescent probe (DAF-2 DA) and pH-specific fluorescent probe (BCECF-AM) based laser scanning confocal microscopy,the role of Phyto-S1P in darkness-induced stomatal closure of Vicia faba was explored via detecting stomatal aperture and the changes of NO and pH levels.【Result】Darkness substantially induced stomatal closure and raised nitric oxide (NO) levels in Vicia faba.These effects could be significantly suppressed by DL-threo-dihydrosphingosine (DL-threo-DHS) and N,N-dimethylsphingosine (DMS),two inhibitors of long chain base kinases (LCBKs).Exogenous Phyto-S1P evidently induced stomatal closure and raised NO levels,which could be largely prevented by NO modulators 2-(4-carboxyphenyl)-4,4,5,5 tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) and NG-nitro-L-Arg-methyl ester (L-NAME). These results suggested that Phyto-S1P mediated darkness-induced stomatal closure through inducing NO production.Additionally,darkness induced increase in cytosolic pH and stomatal closure could be significantly suppressed by DL-threo-DHS and DMS.Exogenous Phyto-S1P obviously caused increase in cytosolic pH and stomatal closure,which could be largely inhibited by butyric acid.These results indicated that Phyto-S1P involved in darkness-induced stomatal closure via inducing cytosolic alkalization.Phyto-S1P-caused pH increase had a shorter lag,and reached the peak faster than that of NO levels and Phyto-S1P-induced NO production was inhibited by butyric acid,which further confirmed the conclusion that Phyto-S1P-caused cytosolic alkalization was a prerequisite for NO production.【Conclusion】Phyto-S1P mediated darkness-induced Vicia faba stomatal closure via causing cytosolic alkalization and NO production.Cytosolic alkalization was the inducing factor for NO production in the process. |
| Key words: phytosphingosine-1-phosphate cytosolic pH nitric oxide darkness induced stomatal closure Vicia faba L. |
