Tissue-specific expression pattern of shikimate kinase from Cassia obtusifolia L. was analyzed and then the total anthraquione content in different organs was determined, which aimed at providing a theoretical basis for the study of the role of shikimate kinase from Cassia obtusifolia in anthraquinone biosynthesis. The total RNA of nonage seed, callus and mature leaves and so on of C. obtusifolia were extracted and subjected for cDNA synthesis. The expression quantitative analysis of CoSK in different tissues was estimated by real-time PCR. At the same time the anthraquione was extracted by ultrasonic extracting method, and the total anthraquione contents were determined by UV. Shikimate kinase showed a significantly high expression level in the root, callus and cotyledon of C. obtusifolia and a relatively low expression level in stem, pod and nonage seed. Anthraquione illustrated high content in seeds, pod, flowers and roots of C. obtusifolia, whereas mature leaves and hypocotyls did not find anthraquinone. The biosynthesis of C. obtusifolia in anthraquinone involved multiple organizations and in early stages (including shikimate kinase-

catalyzed reaction) occured mainly in roots and mature leaves and other tissues. The intermediate products

were transported to seeds and other tissues and completed the later stages of the biosynthesis and

accumulation of anthraquinone final product, which was supposed to provide a guideline for the rational

utilization of different medicinal parts of C. obtusifolia.

Cassia obtusifolia L., shikimate kinase, tissue-specific expression, total anthraquione, content