对离体培养青蒿试管苗中3个青蒿素合成相关基因的非生物胁迫诱导表达模式进行了初步研究.半定量RT—PCR测定结果表明,当暴露于冷、热和紫外光后,青蒿植株的紫穗槐-4,11-二烯合酶基因(ADS)和细胞色素P450单加氧酶基因(CYP71AV1)转录上调;相反,在未经胁迫处理的情况下,ADS和CYP71AV1基因的表达水平较低,而在胁迫处理前后细胞色素P450还原酶基因(CPR)转录所产生的mRNA均保持恒定.同时,冷胁迫的诱导效果也得到实时荧光定量RT—PCR测定数据的支持.经低温锻炼的青蒿试管苗,其ADS和CYP71AV1基因的转录产物拷贝数比对照分别提高11倍和7倍,而CPR基因的mRNA拷贝数与对照基本持平.短暂预冷处理还可显著提高青蒿试管苗的青蒿素含量,达到7.5—8.8mg/g干重,比对照提高66.7%-95.6%,为进一步探索利用环境胁迫促进青蒿素高产的新途径提供了可能性.图2表3参21
The abiotic stress-induced expression pattern of three genes responsible for artemisinin accumulation was preliminarily elucidated in cultured Artemisia annua plants. The semi-quantitative RT - PCR determination showed that upon exposure to chilling, heat shock or UV light, the transcription levels of amorpha-4,11-diene synthase gene (ADS) and cytochrome P450 monooxygenase gene (CYPT1AV1) were up-regulated; In contrast, under the circumstance without stress treatments, the expression levels of ADS and CYPT1AV1 genes were relatively low, while the mRNA generated by the transcription of cytochrome P450 reductase gene (CPR) remained stable under pre-and post-treatments. The induced outcome by chilling stress was also supported by the measurement data from real-time fluorescent quantitative RT - PCR. Consequently, for A. annua shoots acclaimed by low temperature, the transcripts of ADS and CYPT1AV1 genes were 11 folds and 7 folds higher than those of the control, but the CPR mRNA copy was almost equivalent to the control. Furthermore, a transient pre-chilling treatment led to an elevated artemisinin content up to 7.5-8.8 mg/g dry weight (DW) , i. e. , increased by 66.7%-95.6% as compared with the control, thereby providing an open space for enhanced artemisinin production by the environmental stresses. Fig 2, Tab 3, Ref 21