转基因烟草在PEG6000模拟干旱胁迫条件下的生理响应

Physiological response of transgenic tobacco to drought stress simulated by PEG6000

关键词:  PEG6000模拟干旱胁迫, CbPLDα, CbPLDβ, 渗透调节物质, 保护酶

Key words:  drought stress simulated by PEG6000, CbPLDα and CbPLDβ, osmolytes, protective enzyme

摘要:

该研究以转高山离子芥的CbPLDα、CbPLDβ基因烟草为材料,研究了渗透调节物质和保护酶系对PEG6000溶液模拟干旱胁迫的响应机制。结果表明:渗透调节物质脯氨酸、可溶性糖、可溶性蛋白分别以各自不同的响应方式在干旱胁迫下增强转基因烟草的抗旱性,且在所有浓度PEG6000模拟的干旱胁迫下,转基因烟草的脯氨酸、可溶性糖、可溶性蛋白的含量始终显著高于野生型烟草(P<0.05)。说明干旱胁迫下两种转基因烟草的渗透调节能力要强于野生型烟草。保护酶系中,超氧化物歧化酶(SOD)和过氧化物酶(POD)在减轻干旱胁迫下转基因烟草膜脂过氧化伤害中起到协同互补作用,而过氧化氢酶( CAT)和抗坏血酸过氧化物酶( APX)在干旱胁迫下转基因烟草清除过氧化氢机制中发挥主要作用,说明保护酶系在抵制干旱胁迫和保护转基因烟草免受干旱伤害方面具有重要的生物学功能,这从生理角度揭示了高山离子芥CbPLDα、CbPLDβ响应干旱的生理生态机理。综上,高山离子芥CbPLDα、CbPLDβ基因参与了干旱胁迫下烟草的膜稳定性调节、渗透调节物质的积累和抗氧化酶系的调控。该研究结果为提高植物抗旱性研究及应用提供了新的基因资源,对于加强PLD功能研究、补充植物抗干旱理论及抗低温干旱育种种质资源的开发利用具有重要意义。

Abstract:

Chorispora bungeana is a rare alpine subnival plant species, the extremely harsh living environment makes it become a new plant for study the responses of drought stress. In this study we used CbPLDα, CbPLDβ transgenic tobacco plants as material to find the mechanism of plants response drought stress, and we also detected the osmolytes content and protective enzymes activity in CbPLDα, CbPLDβ transgenic tobacco plants, using the ways of the drought stress simulated by PEG6000. The results showed that proline, solube sugar and soluble protein involved in strengthening resistance of CbPLDα, CbPLDβ transgenic tobacco to drought stress simulated by PEG6000,and in different concentrations of PEG6000 simulate drought stress, CbPLDα, CbPLDβ transgenic tobacco proline, soluble sugar and soluble protein content were always significantly higher than that of wild type tobacco plants(P<0.05). This indicated that osmotic adjustment ability of drought stress in CbPLDα and CbPLDβ transgenic tobacco was stronger than the wild type tobacco plants. In the protective enzymes, Superoxide dismutase(SOD)and Peroxidase(POD)have significant complementary effects on mitigating the injury of membrane lipid peroxidation of transgenic tobacco; Catalase(CAT)and Ascorbate peroxidase(APX)played major roles in the mechanism of removal of hydrogen peroxide. SOD,POD,CAT and APX had higher activity in CbPLDα, CbPLDβ transgenic tobaccos than in wild tobacco plants(P<0.05). All of these results indicated that protective enzymes had important biological function in protecting transgenic tobacco from drought stress simulate by PEG6000. It partly revealed the physiological and ecological mechanisms of the CbPLDα, CbPLDβ genes responding to drought environment in C. bungeana. The results showed that both CbPLDα and CbPLDβ transgenic tobaccos involved in the regulation pathway of membrane stability, osmotic adjustment and the regulation of anti-oxidative system. CbPLDα and CbPLDβ genes can provide powerful genetic resources for improving drought resistance of plants. The results strengthen the PLD for functional studies, supplementary plant resistance to drought stress and drought resistance theory breeding germplasm development and utilization, has important theoretical value and practical significance.