不同低温胁迫对烟草愈伤组织抗氰交替途径诱导和交替氧化酶表达影响的比较(英文)

Comparison of the Effects of Different Low Temperature Stresses on the Induction of the Cyanide-Resistant Alternative Pathway and the Expression of Alternative Oxidase in Tobacco Callus

比较了不同低温(14℃和4℃)胁迫对烟草(Nicotiana rustica L.)愈伤组织抗氰交替途径诱导和交替氧化酶表达的影响。 结果显示,不同低温胁迫处理能显著诱导烟草愈伤组织交替途径容量和实际运行的增加,且都呈现出基本相同的变化模式:在胁迫的初期(1～3 d)持续增加,在3 d时达到最高,而后下降到一个相对恒定的水平。但交替途径容量增加的幅度与温度下降的程度密切相关,而交替途径实际运行量的诱导程度在不同低温胁迫下的差异却很小。 表明交替途径容量和实际运行对低温胁迫的响应是不同的。免疫印迹分析结果表明:低温胁迫明显诱导了交替氧化酶总蛋白的增加,且其随低温胁迫进程的变化与交替途径容量的变化基本一致;而对交替氧化酶单体与二聚体在低温胁迫下的含量变化检测结果则显示,烟草愈伤组织中交替氧化酶主要以二聚体形式存在,且这一存在形式并不随低温胁迫程度的加深而发生改变。两种形式的交替氧化酶蛋白含量都能被低温胁迫诱导增加,但其单体水平在两种不同的低温胁迫下并无明显差别,而4℃低温胁迫诱导的二聚体交替氧化酶蛋白含量明显高于14℃。表明不同程度低温对抗氰交替途径发生的不同影响主要是由于对交替氧化酶蛋白二聚体形式的不同诱导程度所致;

Effects of different low temperature stresses (14℃ and 4℃) on cyanide-resistant alterna-tive pathway development and operation, as well as on alternative oxidase expression in plant calli oftobacco (Nicotiana rustica L.) were compared. The results showed that both alternative pathwaycapacity (Valt) and its actual operation activity (rValt) were dramatically induced under the twodifferent low temperature stresses, and the change patterns of Valt and rValt were similar: both ofthem were induced at the early stage of stress treatment, the highest was found on 3 d and thendeclined to a relatively constant level. The increase of Valt was in relation to the temperature decreased,while no significant difference of rValt induced between 14℃ and 4℃. This suggests that responsesof Valt and rValt to different temperature stress are different. The immunoblot results indicated thatlow temperature stress remarkably induced the content of total alternative oxidase (AOX) protein,and the changing mode throughout the stress was similar to Valt. The results of variation in AOXmonomer and homodimer contents under stress treatment showed that AOX is largely located inmitochondria membrane of tobacco callus as the oxidized form (homodimer), and the existing statecould not be changed by low temperature stress. The amount of monomer and homodimer bothinduced by low temperature stress, but no appreciable differences in the content of monomer wasobserved between two different low temperatures, and the level of homodimer induced under 4℃ washigher than that under 14℃. Our results suggest that, effects of low temperature on the developmentof cyanide-resistant alternative pathway are mainly due to the differently induced content of AOXhomodimer under different low temperatures. The content of highly active AOX monomer form is notobviously induced by aggravating low temperature stress, thus the operation degree of cyanide-resistant alternative pathway shows no notable difference between two kinds of low temperaturestested.