高温胁迫对烟草叶绿体NADPH脱氢酶复合体活性的促进  

Stimulation of Activity of Chloroplast NADPH Dehydrogenase Complex by Elevated Temperature in Tobacco

作　　者：姚正菊[1] 叶济宇[1] 米华玲[1] 

机构地区：[1]中国科学院上海生命科学研究院植物生理生态研究所

出　　处：《植物生理与分子生物学学报》2003年第5期395-400,共6页Journal Of Plant Physiology and Molecular Biology

基　　金：国家重点基础研究发展规划项目 (No .G19980 10 10 0 );国家自然科学基金项目 (No .3 0 2 70 12 3 )资助

摘　　要：为探讨叶绿体NAD(P)H脱氢酶复合体 (NDH)在植物抵御热胁迫中的生理意义 ,比较了烟草ndhJK基因缺失突变体 (ΔndhJK)和野生型对 5 0℃高温胁迫的响应。高温下 ,野生型中一条NBT NADPH氧化还原酶活性带有所增加 ,免疫印迹分析确定了此活性染色带是NDH亚复合体 ,该活性带中的NDH K表达量也在热胁迫条件下明显地增加。与ΔndhJK相比 ,在高温胁迫下 ,野生型中远红光诱导的P70 0氧化速率明显地变慢 ,而远红光关闭后的P70 0暗还原速率则显著地变快 ,表明高温促进NDH介导的围绕光系统I的循环电子传递。根据这些结果推测 ,在热胁迫条件下野生型中对NADPH底物专一的NDH活性的增加可能有利于减少NADPH的积累 ,减轻叶绿体间质的过度还原。To investigate the role of chloroplast NADPH dehydrogenase complex (NDH) in protecting plants against heat stress, responses to elevated temperature at 50℃ were compared between ndh JK defective mutant (ΔndhJK) and its wild type (WT). An activity band of NADPH NBT oxidoreductase in WT increased at the elevated temperature (Fig.1). Western blotting analysis indicated that the activity band was a subcomplex of NDH (Figs.2 and 3) and expression of NDH K also increased evidently at the elevated temperature (Fig.2). The rate of re reduction of P700 + after turning off the far red light (FR) was much faster and the rate of the oxidation of P700 induced by FR was much slower in WT than in ΔndhJK (Fig.4), indicating that the NDH mediated cyclic electron flow around PSⅠ was stimulated by the elevated temperature. We deduce that the increase in activity of NADPH specific NDH at elevated temperature probably functions in removing extra NADPH to prevent overreduction of stroma.

关 键 词：热胁迫 NADPH脱氢酶复合体 循环电子传递 

分 类 号：Q945[生物学—植物学]