TMV感染烟草叶片类囊体膜对热胁迫更敏感

Sensitivity of Thylakoid Membrane of TMV Infected Tobacco Leaves to Heat Stress

分别利用吸收光谱、荧光发射光谱、温和电泳和SDS-PAGE的方法分析比较热胁迫(35～65℃)对TMV感染或未感染TMV的烟草叶片类囊体膜结构和功能的影响.结果表明,未感染TMV的叶片类囊体膜可见光区吸收峰强度在25～45℃温度范围内随处理温度升高而增加,而TMV感染的几乎没有变化;未感染TMV的叶片类囊体膜叶绿素a荧光发射峰强度也随处理温度显著变化,35或45℃时荧光峰强度分别降低了19.5%和37%,65℃时减少到23.3%,而TMV感染的也显著降低.温和电泳和SDS-PAGE结果表明,热胁迫均引起感染TMV或未感染TMV的叶片类囊体膜色素蛋白发生明显变化,如游离色素叶绿素增多,光系统Ⅱ和I复合体解聚成单体,类囊体膜上的重要功能蛋白含量减少,产生聚合物,尤其经TMV感染引发的该变化更加明显.说明TMV感染烟草提高了类囊体膜对热胁迫的敏感性.

With absorption spectra,fluorescence emission spectra,native electrophoresis and SDS-PAGE methods,the structure and function of thylakoid membrane under heat stress（25～65 ℃） were compared between normal or the TMV infected tobacco leaves.The results showed that the absorption peak intensity from normal leaves increased as temperature rose,while that from the infected leaves hardly changed at 25～45 ℃.The intensity of chlorophyll a emission fluorescence peak also obviously changed depending on temperature,and fluorescence peak intensity decreased by 19.5% and 37% at 35 ℃ and 45 ℃,and decreased by 23.3% at 65 ℃,while the fluorescence intensity of the infected sample also decreased notablely.The result of native electrophoresis and SDS-PAGE showed that heat stress caused the obvious change in the composition of pigment binding protein of thylakoid membrane,such as increase in free chlorophyll,formation of the aggregates,degradation of trimmer into monomer of PSⅡand PSⅠcomplex and obvious decrease in important function protein of thylakoid membrane,while the thylakoid membrane of the TMV infected leaves was obviously affected,indicating its sensitivity to heat stress by the insertion of the coat protein induced by the TMV.