Stable transfer and expression of chimeric genes in licorice (Glycyrrhiza uralensis) using an Ri plasmid binary vector.

The pharmaceutically important plant, licorice (Glycyrrhiza uralenesis Fisher), was transformed with a binary vector system of an Ri plasmid, pRi15834, and a mini Ti vector, pGSGluc1, containing chimeric neo and gus genes. The transgenic state of transformed roots was confirmed by detection of agropine and mannopine and by Southern blot hybridization with T-DNA of pGSGluc1. One to three copies of T-DNA of pGSGluc1 was integrated into the genomic DNA of G. uralensis. The expression of chimeric neo and gus genes driven by TR 1' and 2' promoters, respectively, was demonstrated by enzymatic assays. Histochemical analysis showed that the chimeric TR2'-gus gene was expressed specifically in phloem and pericycle tissues of the transformed licorice roots.