Catharanthus roseus, commonly known as the Madagascar Periwinkle, produces two important anticancer compounds, vinblastine and vincristine, in its defense response. However, very low levels of these compounds are produced (0.0002 wt%), as large quantities are toxic to the plant itself. While the pathway that produces these compounds has been determined, its regulation is not well understood. By studying the role of these regulators (called transcription factors), we can engineer the expression of regulators that enhance production.
In this project, C. roseus root lines with certain genes overexpressed or silenced were developed to study the effect of the transgenes on growth and production of the compounds. The roots were inoculated in six-well plates with fresh media, and images were taken every two to three days. To calculate the roots’ growth rates, a method was developed that applies imaging and mathematical modeling to calculate the doubling time of the roots; this method allows growth to be monitored in situ without risk of contamination by opening the plates. These data were then used to determine whether the transgene had a statistically significant effect on growth. Additionally, PCR and gel electrophoresis were used to verify that the genes of interest were integrated into the DNA.
We will compare the growth rates and compound production of these transgenic roots to better understand how these genes influence growth and production of the medicinal compounds.