POTENTIALITY OF CAMBIUM AND LEAF EXPLANTS FOR GENETIC TRANSFORMATION OF ELMS

Somatic hybridisation is an alternative to improve elm resistance to DED. In order to introduce selectable markers in the potential parents, the ability for genetic transformation of elm “cambium” explants and leaf discs was tested. After coculture with A. tumefaciens LBA4404 -pKYGUSint. (+ pNOS NPTII), “cambium” produced green shoots on kanamycin containing medium (250 mg 1^-1). Shoots did not root on kanamycin medium (50 mg 1^-1) and PCR analysis with uidA primers were negative. After coculture with GV3101-pMP90 (pKYGUSint.) and decontamination with ticarcillin, GUS expression was observed until bud induction. Therefore, although shoot regeneration process was reduced, leaf discs seemed the best explant for future transformation experiments.