Wednesday, November 7, 2007

The Effect Of Uvb Light On Terpenoid Indole Alkaloid Production In Catharanthus Roseus Hairy Roots

Bernard Y. K. Binder1, Christie A.M. Peebles, Jacqueline V. Shanks2, and Ka-Yiu San3. (1) Dept of Bioengineering, Rice University, Houston, TX 77005, (2) Chemical and Biological Engineering, Iowa State University, 2114 Sweeney Hall, Ames, IA 50011, (3) Department of Bioengineering, Rice University, MS-142, PO Box 1892, Houston, TX 77005

The Madagascar periwinkle, Catharanthus roseus, produces a number of terpenoid indole alkaloids (TIA) with useful pharmaceutical applications, including the treatment of leukemia and lymphoma with vinblastine and vincristine. Although C. roseus generally contains relatively low levels of these alkaloids, it has been reported that exposure to ultraviolet light in the 280320 nm (UVB) range stimulates production and accumulation of TIAs in multiple shoot cultures of transgenic plants. We are interested in studying the effect of UVB light on C. roseus hairy roots.

An endpoint investigation of the effects of 0, 5, 10, and 20 minutes of UVB light exposure on TIA production showed that the TIA content significantly increased as UVB exposure time increased when the roots were harvested 72 hours after exposure. Here we will discuss the transient effect of exposing C. roseus hairy roots to 20 minutes of UVB light on TIA accumulation over time. The changes in TIA levels were tracked 0, 6, 12, 24, 36, 48, and 72 hours after exposure along with changes in mRNA levels in tryptophan decarboxylase, geraniol 10-hydroxylase, and strictosidine synthase.