Saffron possesses important medicinal properties, all of which are due to the secondary metabolites such as crocin, picrocrocin, and safranal. This study aims at investigating biosynthesis of the secondary metabolites during growth of saffron callus cells in a suspension culture, and examining the expression of genes controlling the metabolites. Sterilized saffron corms were cultured in a MS½ medium supplemented by 2-4-D and BAP. The calluses were induced after fourteen days, and then put into the suspension culture after being four times subcultured. From the 8th to 14th day after establishment of the suspension culture, the amount of secondary metabolites was measured by HPLC, and gene expressions were analyzed with real-time PCR for three samples taken once a day at the same time from the suspension. It was found that the amount of secondary metabolites and expression of the corresponding genes ( CsLYC , CsBCH and CsGT 2 ) were saturated on the 12th day after establishment of the suspension. For the most effective stimulation of genes and biosynthesis of apocarotenoids, suitable elicitors and precursors should be added within 72 h before saturation of the synthesis rate which happens on the 12th day after establishment of the suspension.

中文翻译：

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藏红花 (Crocus sativus) 细胞悬浮培养中藏红花素和番红醛生物合成相关基因的表达

藏红花具有重要的药用特性，所有这些特性都是由于次生代谢产物，如藏红花素、苦藏红素和番红花醛。本研究旨在研究悬浮培养中藏红花愈伤组织细胞生长过程中次生代谢物的生物合成，并检查控制代谢物的基因的表达。灭菌的藏红花球茎在补充有 2-4-D 和 BAP 的 MS1/2 培养基中培养。14天后诱导愈伤组织，传代4次后放入悬浮培养。从悬浮培养建立后的第8天至第14天，通过HPLC测量次级代谢物的量，并通过实时PCR分析每天一次从悬浮液中同时采集的三个样品的基因表达。发现在悬浮液建立后第12天次级代谢产物的量和相应基因(CsLYC、CsBCH和CsGT 2 )的表达达到饱和。为了最有效地刺激基因和类胡萝卜素的生物合成，应在悬浮液建立后第 12 天合成速率饱和前 72 小时内加入合适的诱导剂和前体。