Abstract:

The oligosaccharide elicitor from the mycelial wall of an endophytic Colletotrichum sp. B501 promoted the production of artemisinin in Artemisia annua L. hairy root culture. When hairy roots of 22 day old cultures (later growth phase) were exposed to the elicitor (20 mg/L) for 4 d, the maximum content of artemisinin reached 1.15 mg/g, a 64.29% increment over the control. The electron X ray microanalysis disclosed the rapid accumulation of Ca2+ in the elicited cortical cells of hairy root. The electronic microscope observation revealed the high electron density area in vacuole of elicited cells. During the first day of elicitation the peroxidase activity of hairy roots was improved sharply. Some cellular morphological changes including cell shrinkage, condensation of cytoplasm and nuclear fragmentation, coincident with the appearance of DNA ladders, were observed after the third day of elicitation. It was suggested that the oligosacc haride elicitor triggered the programmed cell death, which may provide the subst ance or chemical signal for artemisinin biosynthesis.

内生真菌 Colletotrichum sp. B501的寡糖提取物对黄花蒿发根中青蒿素生物合成的诱导
王剑文 夏仲豪 谭仁祥*

（南京大学功能生物分子研究所，南京210093）

在黄花蒿 (Artemisiaannua L .)发根液体培养中 ,黄花蒿内生炭疽菌 (Colletotrichum sp .B5 0 1)细胞壁寡糖提取物可促进发根青蒿素的合成。经寡糖诱导子 (2 0mg/L)处理 4d后 ,发根青蒿素含量达 1.15mg/g ,比对照高出6 4 .2 9%。诱导作用与诱导子浓度、作用时间相关。诱导处理 1d后 ,X射线能谱分析表明黄花蒿发根细胞中Ca^{2 +} 积累量显著增高 ,电镜观察发现液泡内出现高电子致密物 ,具活性氧清除作用的过氧化物酶表现出高活性 (6 .5unit·min^-1·g-¹FW)。诱导处理第三天 ,细胞核DNA呈梯度条带降解 ,部分细胞出现程序化死亡。内生菌细胞壁寡糖提取物引起的生理反应有利于细胞中青蒿素的生物合成。
 

关键词： 黄花蒿；内生真菌；寡糖诱导子；青蒿素；诱导反应

Key words: Artemisia annua, Colletotrichum sp. B501, a fungal endophyte, oligosac charide elicitor, artemisinin, eliciting response