Analysis of MEV6 Transgenic Taraxacum kok-saghyz (TK) for Increased Rubber Yields and Altered Photosynthetic Rates

David Lankitus
Graduate (PhD)
Katrina Cornish
Horticulture and Crop Science

Taraxacum kok-saghyz (TK) is a plant species under development for use as a rubber crop in Ohio. Poor agronomic traits prevent TK from being grown commercially, but these traits can be improved by genetic engineering. One such approach is through the insertion of six genes designed to improve isopentenyl pyrophosphate (IPP) concentrations via increased gene products from the mevalonate pathway. This gene insertion, called MEV6, has been propagated to its third generation. The objective of this project is to evaluate TK traits as a result of the MEV6 transformation. Traits studied are rubber concentration, measured as mg rubber per g root dry weight; rubber yield, measured as mg rubber per whole plant; and photosynthetic rate, measured as umol/m2/s. This T3 generation was grown for 9-10 months to maturity. Plants were then harvested and weighed, then roots were dried in a 50 degree C oven for, at minimum, one week, then were weighed again and ground to a powder. Ground root samples were analyzed using near-infrared spectroscopy (NIR), and rubber concentrations will be determined based on a previously built model using Accelerated Solvent Extraction as the reference quantification method. Data is in early stages of analysis, but trends in this data suggest interesting results. After measuring photosynthetic rates, there does not appear to be a correlation between transgenic plants and photosynthetic rate. This will be analyzed again in the T4 generation. Root dry weight comparisons also suggest larger roots in suspected T3 MEV6 plants. PCR confirmation for progeny are also required to confirm results. Dried and ground root samples will continue to be studied using NIR to calculate both rubber concentration and rubber yield in all T3 plants.