Expression of the hyp-1 gene in early stages of development of Hypericum perforatum L.
Level of expression of the hyp-1 gene encoding for the phenolic coupling protein which is assumed to be involved in conversion of emodin to hypericin in vitro was compared in different organs of Hypericum perforatum seedlings in early stage of development in order to find out the sites of hypericin biosynthesis. Hypericins are accumulated in multicellular dark glands distributed on the aerial parts of H. perforatum, however, the site of the final stages of their biosynthesis remains unclear. In order to verify biosynthetic capacity of the dark glands, the level of expression of the hyp-1 gene in root, stem, shoot apex, intact leaf, leaf lamina free of and leaf margins containing dark glands performed by quantitative reverse transcription real-time PCR (qRT-PCR) was compared. The results did not reveal any significant difference in the level of hyp-1 expression in the analyzed leaf tissues. Surprisingly, the highest expression level was found in roots, which contain neither any dark glands nor more than just traces of hypericin. The lowest expression level was found in the plant stem and shoot apex. The results may either indicate that the final stages of hypericin biosynthesis take place in different plant parts, mainly in roots, which are not essentially associated with the dark glands and primarily serve for hypericin accumulation or rise a question on the coding function of the respective gene in situ.