低温胁迫下油菜素内酯对高山离子芥悬浮细胞膜系统的影响

Effect of brassinosteroids on the membrane system of Chorispora bungeana suspension-cultured cells under chilling stress

摘要:

为研究低温胁迫下油菜素内酯(brassinosteroids, BRs)对植物细胞膜系统的影响,使用24-表油菜素内酯(24-epibrassinolide, EBR)在4 ℃处理高山离子芥(Chorispora bungeana)悬浮细胞.结果显示,低温胁迫下高山离子芥悬浮细胞的离子渗漏率和丙二醛(MDA)含量明显升高,而EBR处理显著降低了细胞的离子渗漏率和MDA含量.此外,低温胁迫下,EBR处理在一定程度上提高了膜脂脂肪酸不饱和程度并明显增强了细胞质膜H+-ATPase，K+-ATPase，Ca2+-ATPase以及Mg2+-ATPase的活性.另外,低温诱导CbCOR15基因大量表达.而在低温胁迫初期,EBR处理细胞的CbCOR15基因表达水平更高.以上实验结果表明,EBR在稳定低温胁迫下高山离子芥悬浮细胞膜系统的结构与功能方面发挥积极作用,从而保证细胞生理代谢的正常进行,以提高其抗寒能力.

关键词:油菜素内酯;高山离子芥;低温胁迫;膜系统;抗寒性

Abstract:

In order to explore the effect of brassinosteroids (BRs) in plant cell membrane systems subjected to chilling stress, suspension-cultured cells of Chorispora bungeana were treated with 24-epibrassinolide (EBR) at 4 ℃. The results showed that under chilling stress, ion leakage and malondialdehyde (MDA) content were increased obviously in the cultured cells, but they were significantly decreased by EBR treatment. Besides, under chilling conditions, treatment with EBR obviously increased the unsaturation of membrane fatty acids and remarkably enhanced the activities of plasma membrane H+-ATPase, K+-ATPase, Ca2+-ATPase and Mg2+-ATPase. Furthermore, the expression of CbCOR15 was highly responsive to low temperature. The CbCOR15 was expressed at a much higher level in EBRtreated cells at the early stage of chilling stress. All the results indicated that EBR could play a positive role in stabilizing the structure and function of cell membranes under low temperature conditions, thereby ensuring the normal physiological metabolism of cells to improve its chilling tolerance.

Key words:Brassinosteroids; Chorispora bungeana; Chilling stress; Membrane system; Chilling tolerance