Glycoside Content in Rhodiola rosea L.: Dynamics and Expression Pattern of Genes Involved in the Synthesis of Rosavins

摘要

The most important pharmaceutically active compounds of Rhodiola rosea are glycosides, which are accumulated in the rhizome of the plant. The aim of the study was to investigate the dynamics of the glycoside content of the rhizome and the leaves during the vegetation period with HPLC. Along with this the expression of the genes involved in the biosynthesis of the rosavins were studied with qPCR.Expression analysis of the genes encoding for phenylalanine ammonia lyase (PAL), 4-coumarate-CoA ligase (4CL), cinnamoyl-CoA oxidoreductase (CCR), cinnamyl alcohol dehydrogenase (CAD) was done by qPCR.Results of the HPLC analysis showed that traces of the glycosides are present in the leaves, only, while in the rhizomes salidroside content was 0.5-4.5%, rosincontent was 0.01-0.1%, rosavin content was 0.02-2.37% and rosarin content was 0.1-0.55% of the dry weight. The 4 biological repetitions showed very big deviation, no clear trend could be observed.Statistical analysis of the relative gene expression values showed, that the expression of 4CL in the rhizome was the most similar in the 4 biological repetitions, showing a decrease during flowering and then rising to the initial level. In case of PAL the 4 repetitions had higher diversity in the rhizome samples, while in case of 4CL, CAD higher diversity was observed in case of the leaf samples. CCR was equally diverse both in the rhizome and in the leaf samples. Linear regression analysis showed thatmostly the expression of CCR and to a lesser extent of CAD and PAL had effect on the content of the cinnamyl alcohol glycosides.Based on the results it is not possible to conclude the expression profiles of neither the genes nor the accumulation pattern of the glycosides. Environmental factors and plant age certainly have major effect.