Update:
54 transgenic events were created, of which 8 contained the Rs2 gene transformed to reduce raffinose synthase expression to varying degree. The first two constructs were quantified as to raffinose level compared to the control (wild type). One expressed at 41.66% and another at 35.60% of the control. Thus, transgenic modification is possible of the Rs2 gene for raffinose.
The transgenic versions of the Rs2 raffinose synthase gene may not be too useful in the real world given the number of natural mutants available. Still, they may prove useful as research subjects in efforts to quantify, in feeding trials, the degree of metabolizable energy available to animals afforded by the degree of sucrose and oligosaccharides in the meal.
We have produced sufficient transgenic homozygous RS2 seeds under the field conditions and used these seeds to conduct kicks feeding test. We found that transgenic seeds increased true metabolizable energy of poultry feed. As a result we have published the results in Front Plant Sci (doi: 10.3389/fpls.2017.00692).