Regeneration of phenotypically normal English elm (Ulmus procera) plantlets following transformation with an Agrobacterium tumefaciens binary vector

A transformation system was developed for English elm (Ulmus procera Salisb ury) using Agrobacterium tumefaciens C58 pMP90 p35SGUS/INTRON, allowing for the transfer of foreign genes and regeneration of phenotypically normal el m plantlets. The PCR analysis indicated that both nptII and uidA genes were stably inserted in the plant genome. beta-Glucuronidase histochemical and fluorimetric assays revealed expression of the uidA gene in the shoots, lea ves, stems and roots of regenerated transgenic plants. The DNA-DNA hybridiz ations confirmed the presence of the uidA gene in regenerant plants. Factor s influencing successful transformation and regeneration of elms included: identifying gene-transfer-proficient Agrobacterium strains for use with elm s; developing an infection protocol allowing T-DNA transfer while retaining the ability to remove inciting bacteria; and identifying selection conditi ons to eliminate non-transformed material and choice of regeneration medium to allow shoot production. The potential utility of an effective elm trans formation and regeneration system in the control of Dutch elm disease is di scussed.