低温胁迫下脱落酸对线粒体膜磷脂酶D活性的影响

Effects of abscisic acid on PLD activity in mitochondrial membrane under low temperature

关键词:  低温胁迫, 高山离子芥, 脱落酸, 磷脂酶D, 信号转导

Key words:  low temperature stress, Choraspora bungeana, abscisic acid(ABA), phospholipase D, signal transduction

摘要:

高山离子芥(Choraspora bungeana)是一种稀有高山冰缘植物,其生活环境具有低温、强紫外线等胁迫因子。PLD在膜磷脂降解及磷脂信号转导过程中发挥着重要作用,但其活性往往受到多种因素的影响。该研究以高山离子芥试管苗为材料,研究了4 ℃、0 ℃和-4 ℃胁迫下,ABA对高山离子芥试管苗叶中线粒体膜结合态PLD活性的影响。结果表明:10, 50和100 μmol·L^-1 脱落酸(ABA)处理高山离子芥后,线粒体膜结合态PLD活性均较未添加ABA的处理组线粒体膜结合态PLD活性高,其中以50 μmol·L^-1 ABA对离子芥叶中线粒体膜结合态PLD活性的促进作用最为显著; 外施0.3 mmol·L^-1 的ABA合成抑制剂钨酸钠处理高山离子芥后,线粒体膜结合态PLD活性较对照组线粒体膜结合态PLD活性降低; 在50 μmol·L^-1 ABA + 5 mmol·L^-1 EGTA处理组中,高山离子芥叶中线粒体膜结合态PLD活性低于未添加EGTA处理组线粒体膜结合态PLD活性; 在0.3 mmol·L^-1 钨酸钠 + 10 mmol·L^-1 CaCl₂处理组中,高山离子芥叶中线粒体膜结合态PLD活性高于未添加CaCl₂处理组线粒体膜结合态PLD活性。由此推测,低温胁迫下ABA可能通过Ca²⁺介导影响高山离子芥叶中线粒体膜结合态PLD的活性。

Abstract:

Choraspora bungeana is a kind of rare alpine periglacial plant. The environment that C. bungeana lives in has many stress factors such as low temperature, strong ultraviolet. PLD plays an important role in degradation of membrane phospholipids and signal transduction of phospholipids. But the activity of PLD is affected by many factors usually. In this study, the plantlets of C. bungeana was used as experimental materials to study the effects of abscisic acid(ABA)on the mitochondrial membrane bound-PLD activity in the leaves of plantlets of C. bungeana under low temperature(4, 0 and -4 ℃). The results indicated that when plantlets of C. bungeana was treated by 10, 50 and 100 μmol·L^-1 ABA, the mitochondrial membrane bound-PLD activity was higher than that in the group without ABA. Among these concentrations of ABA, 50 μmol·L^-1 ABA was more effective to promote the mitochondrial membrane bound-PLD activity compared with ABA of other concentrations. Sodium tungstate was an inhibitor of endogenous ABA biosynthesis and EGTA was a chelating agent of Ca²⁺, both of them had an important role in researching the signal transduction of ABA and Ca²⁺. When the plantlets of C. bungeana was treated by 0.3 mmol·L^-1 Sodium tungstate, the mitochondrial membrane bound-PLD activity in the leaves of plantlets of C. bungeana was lower than that in the control without sodium tungstate. When the plantlets of C. bungeana was treated by 50 μmol·L^-1 ABA+ 5 mmol·L^-1 EGTA, the mitochondrial membrane bound-PLD activity in the leaves of plantlets of C. bungeana was lower than that in the group without EGTA. When the plantlets of C. bungeana was treated by 0.3 mmol·L^-1 sodium tungstate + 10 mmol·L^-1 CaCl₂, the mitochondrial membrane bound-PLD activity in the leaves of plantlets of C. bungeana was higher than that in the group without CaCl₂. From above results, ABA could affect on the mitochondrial membrane bound-PLD activity in the leaves of plantlets of C. bungeana by Ca²⁺ under low temperature.