Analysis of strigolactone biosynthesis using high-producing plant culture system

培养的月桂草的根产生并散发出曲条精，这刺激了几个种的根寄生属曲条精和orobche。根据其结构，兴奋剂被认为是倍半萜。高等植物中萜类化合物的生物合成有两种途径，即甲基戊四醇磷酸（MEP）途径和甲戊酸途径。利用培养的桃金草（M. dauricum）根对马曲糖醇的生物合成进行了研究，结果表明，MEP途径抑制剂fosmidomycin对桃金草（M. dauricum）根培养滤液对马曲糖的萌发没有影响。用[1-^<13>C]葡萄糖和[2-^<13>C]美伐内酯喂养m.d ururum培养的根，随后用^<13>C- nmr监测^<13>C与马己糖醇的结合，结果显示没有信号富集。用高效液相色谱法纯化培养的牛蒡根提取物，用[2-^<14>C] mevalonolactone喂养，在具有高Striga萌发活性的部分中没有检测到放射性。由此可以得出结论，雌戊二醇不是通过甲羟戊酸途径合成的。像脱落酸一样，曲寡糖也可以通过类胡萝卜素合成。目前，类胡萝卜素在曲寡糖生物合成中的作用正在研究中。

Cultured roots of Menispermum dauricum produce and exude strigol, which stimulates germination of several species of the root parasitic genera Striga and Orobanche. The stimulant has been considered to be a sesquiterpene, based on its structure. Two pathways for terpenoid biosynthesis in higher plants, the methyl erithritol phosphate (MEP) pathway and the mevalonate pathway, have been established. Investigations into strigol biosynhesis, using cultured roots of M dauricum, showed that fosmidomycin, an inhibitor of MEP pathway, did not influence activity of M. dauricum root culture filtrate on Striga germination. Feeding M.dauricum cultured roots with [1-^<13>C] glucose and [2-^<13>C] mevalonolactone and subsequent monitoring of ^<13>C incorporation into strigol by ^<13>C-NMR spectroscopy showed no signal enrichment. HPLC purified extracts of cultured M. dauricum roots, previously fed with [2-^<14>C] mevalonolactone, displayed no detectable radioactivity in fractions showing high Striga germination inducing activity. It could thus be concluded that strigol is not synthesized by the mevalonate pathway. Strigol may be synthesized, as is abscisic acid, via carotenoids. Involvement of carotenoids in strigol biosynthesis is, currently, under investigation.