水杨酸对菊叶薯蓣中薯蓣皂素生物合成的影响

薯蓣皂素为甾体激素药物合成起始原料，主要来源于菊叶薯蓣等薯蓣属植物的块茎或根状茎，因而关于提高菊叶薯蓣中薯蓣皂素含量的研究有重要意义。利用水杨酸处理菊叶薯蓣的离体植株，研究其对薯蓣皂素生物合成的影响及作用机制。100μmol·L－1的水杨酸处理使薯蓣皂素积累量最大，且提高了叶绿素含量和可溶性糖含量，降低可溶性蛋白含量。半定量 RT-PCR 检测基因表达发现，除了法尼基二磷酸（FPP）基因，水杨酸增强菊叶薯蓣角鲨烯合酶（SQS）基因、甲基戊二酰辅酶 A 还原酶（HMGR）基因、环阿屯醇合成酶（CAS）基因的表达。研究结果为提高菊叶薯蓣中薯蓣皂苷的含量、揭示水杨酸促进薯蓣皂素生物合成的机制等研究提供了基础。

Effects of Salicylic Acid on Diosgenin Biosynthesis in Dioscorea composita

Diosgenin,mainly isolated from tubers or rhizomes of Dioscorea composita and other plants of the ge-nus Dioscorea,represents the main starting material for commercial synthesis of pill and corticosteroids.Thus,re-searching for improving diosgenin content of Dioscorea composita has important significance.Effects of salicylic acid (SA)on diosgenin biosynthesis and the underlying mechanisms in D.composita were investigated.The considerable increase of diosgenin level in vitro cultured D.composita by 100 μmol·L-1 SA application was accompanied by the concomitant increase of soluble sugar and chlorophyll content and decrease of soluble proteins.The gene expressions of squalene synthase,3-hydroxy-3-methylglutaryl-CoA reductase,and cycloartenol synthetase but not of farnesyl py-rophosphate synthase were up-regulated by applied SA.These results will facilitate the increment of diosgenin content and uncovering the mechanisms of SA improving diosgenin biosynthesis in D.composite.