Yu uses Agrobacterium as a medium to transfer a fragment of exogenous genetic material (T-DNA, short for "transferred DNA") into a host plant's nuclear DNA genome.
余淑美利用它做為媒介，將構築好的「外源基因」片段（T-DNA）放進農桿菌中，藉由它的感染、入侵，將特定基因帶入植株細胞中。