【摘要】 小麦经过适当高温锻炼可产生获得耐热性,为揭示其分子生物学机理,选取耐热品种邯6172和热敏感品种石新733,对34℃热锻炼和42℃高温胁迫条件下叶片2个热激蛋白基因和6个抗氧化酶基因转录表达进行了荧光定量分析,并测定了热致死时间。结果显示,34℃热锻炼可不同程度地提高耐热品种和热敏感品种叶片的热致死时间,42℃高温胁迫下耐热品种表现出更强耐热性。34℃热锻炼可诱导耐热品种热激蛋白TaHsp70和TaHsp16.9基因在不同时间点出现不同程度表达高峰,植株遭受高温胁迫时基因表达上调幅度更强于热敏感品种。34℃热锻炼,耐热品种和热敏感品种Ta(Cu/Zn)SOD、TaMnSOD、TaApx1、TaApx4和TaApx5的表达均呈现间歇性升高趋势,耐热品种的表达量高于热敏感品种,遭受高温胁迫时基因表达持续上升的幅度相对更大。比较出现峰值的时间,热激蛋白和抗氧化酶基因的表达均不晚于热致死时间。说明,热锻炼可诱导热激蛋白和相关酶类基因上调表达,共同调控小麦获得耐热性。不同小麦品种获得耐热性的程度和持续的时间均不同,热锻炼后获得耐热性强度越大,保持的时间越长,遭遇高温胁迫时耐热性越强。更多还原

【Abstract】 Wheat seedlings can get heat tolerance after exposed to heat acclimation. In order to study the molecular mechanism,heat killing times of leaf were measured and genes expression of heat-shock proteins and antioxidant enzymes were analyzed by qRT-PCR after subjected to heat acclimation at 34 ℃ for 48 h then 42 ℃ for 12 h using heat-tolerance cultivar Han 6172 and heat-susceptible cultivar Shixin 733. Heat tolerance of two wheat cultivars were increased to different degrees after heat acclimation at 34 ℃ and became marked after subjected to 42 ℃,Han 6172 showed more stronger heat tolerance. TaHsp70 and TaHsp16. 9 genes expression could be up-regulated with different degrees in heat-tolerance cultivar after heat acclimation at 34 ℃ too. Based on this,the genes expression were up-regulated stronger in heat-tolerance cultivar than in heat-susceptible cultivar when subjected to 42 ℃.Genes expression of Ta( Cu /Zn) SOD,TaMnSOD,TaApx1,TaApx4 and TaApx5 all could be up-regulated with different degrees in heat-tolerance cultivar after heat acclimation at 34 ℃,and most of their expression level were higher in heat-tolerance cultivar than that in heat-susceptible cultivar. When subjected to 42 ℃,gene expression of Ta( Cu/Zn) SOD,TaMnSOD,TaApx1 and TaApx4 were up-regulated more stronger in heat-tolerance cultivar than that in heat-susceptible cultivar. Compared to the time point of peak,all gene expression were not latter than that of heatkilling time. Those results showed that genes of Hsp and antioxidant enzyme participated in regulating the acquisition of heat tolerance during heat acclimation in wheat seedlings. The acquired heat tolerance were different in different wheat cultivars,the more stronger of acquired heat tolerance after heat acclimation,the longer it can be maintained,and the stronger heat tolerance crop showed after subjected to lethan temperature.更多还原