Transformation by Agrobacterium rhizogenes and regeneration of transgenic shoots of the wild soybean Glycine argyrea.

Glycine argyrea accession G1420 was evaluated for its response to inoculation with Agrobacterium rhizogenes strains LBA9402 and A4T, carrying wild type Ri plasmids, and by strains R1601 and A4TIII with engineered plasmids. Hypocotyls from young seedlings were the most responsive in producing roots at inoculation sites. Root production was also dependent on bacterial concentration. Excised, cultured roots produced green nodular callus which regenerated shoots on SC2 medium containing 1.1 mg l(-1) 6-benzylaminopurine and 0.005 mg l(-1) indole-3-butyric acid. The transformed nature of the roots and of callus regenerating shoots was confirmed by the presence of opines and by dot blot analysis for Ri TL-DNA. Tissues regenerated from roots transformed by A. rhizogenes strains R1601 and A4TIII exhibited NPTII enzyme activity, confirming the stable integration and expression of the chimaeric kanamycin resistance gene in transgenic tissues.