高温胁迫对茄子花青素含量及其合成相关酶活性和基因表达的影响

Effects of high temperature stress on anthocyanin concentration,enzyme activities related to its synthesis and gene expression in eggplant

以紫色茄子(Solanum melongena L.)为试验材料,利用人工气候室进行高温处理。以27℃为对照,测定38℃和45℃条件下处理1 h、3 h、6 h、12 h、24 h、48 h、60 h果皮花青素、类黄酮含量,以及花青素生物合成过程中苯丙氨酸解氨酶(PAL)、查尔酮合成酶(CHS)、查尔酮异构酶(CHI)、二氢黄酮醇还原酶(DFR)、花青素合成酶(ANS)、类黄酮3-葡糖基转移酶(UFGT)的活性,并测定3 h和6 h时关键酶基因的表达。结果表明:与对照相比,随着时间的延长,高温胁迫诱导花青素和类黄酮浓度显著降低,其中45℃较38℃下降幅度大;PAL的活性呈现先升高后降低的变化趋势;CHS、CHI、DFR、ANS、UFGT的活性呈现持续下降的趋势,且高温胁迫下,其活性显著低于对照;处理3 h时,SmPAL、Sm4CL的表达量随着温度的升高逐渐增加,38℃和45℃条件下处理6 h,其表达量均低于对照。SmCHI的表达量在38℃时显著升高,而在45℃时降低至与对照相当的水平。SmF3H、SmANS、SmUFGT表达量的变化趋势基本一致,处理时间相同时,温度越高,表达量越低。上述结果表明,高温胁迫降低了茄子果皮花青素合成关键酶的活性及相关基因的表达量,花青素和类黄酮含量降低。

Purple eggplants(Solanum melongena L.)as plant materials were treated under 27℃(CK),38℃and 45℃in phytotron.The concentrations of anthocyanin and flavonoids were measured at 1 h,3 h,6 h,12 h,24 h,48 h and 60 h after treatment.The activities of phenylalanine ammonialyase(PAL),chalcone synthase(CHS),chalcone isomerase(CHI),dihydroflavonol 4-reductase(DFR),anthocyanidin synthase(ANS),flavonoid 3-O-glucosyltransferase(UFGT)were also determined.The expression levels of genes encoding key enzymes were analyzed at 3 h and 6 h after treatment.The results showed that the concentrations of flavonoids and anthocyanins decreased significantly compared with the control.With the increase of stress time,the activity of PAL increased at first and then decreased;activities of CHS,CHI,DFR,ANS,UFGT showed a continuous descending trend,and their activities were significantly lower than those of the control.The relative expression levels of SmPAL and Sm4CL were increased gradually with the increase of temperature after 3 h treatment.When the treatment time reached 6 h,the relative expression levels under 38℃and 45℃were lower than those of the control.The relative expression level of SmCHI increased significantly at 38℃,but decreased at 45℃to the level of the control.The relative expression levels of SmF3H,SmANS and SmUFGT showed the same trend.The higher the temperature,the lower the expression level.These results indicated that high temperature stress reduced the activities of key enzymes of anthocyanin synthesis and relative expression levels of genes encoding key enzymes for anthocyanin synthesis which resulted in the decrease of the concentrations of flavonoids and anthocyanin in eggplant peel.