STABLE TRANSFORMATION OF TOMATO CELL-CULTURES AFTER BOMBARDMENT WITH PLASMID AND YAC DNA

Stable transformants were obtained after microprojectile particle bomb ardment of tomato cell suspensions (Lycopersicon esculentum cv VFNT Ch erry and L. pennellii). The suspensions were bombarded with tungsten p articles coated with either plasmid (similar to 6.3 kb) or yeast artif icial chromosome (YAC) (80 kb) DNA containing the beta-glucuronidase ( GUS) and neomycin phosphotransferase II (nptII) genes. The YAC DNA con tained an insert of approximately 50 kb of DNA from VFNT Cherry. L. pe nnellii suspensions were more amenable to transformation than VFNT Che rry; more kanamycin-resistant calli were recovered from L. pennelli af ter bombardment with plasmid DNA, and only L. pennellii cells produced transformants after bombardment with YAC DNA. DNA gel blot analysis c onfirmed the presence of the nptII and GUS genes. This analysis also c onfirmed the integration of YAC DNA into the genome of the kanamycin-r esistant calli and suggested that the level of intactness of the integ rated YAC DNA was fairly high in four of the five transformants examin ed. Microprojectile bombardment of regenerable cultures with YACs may ultimately aid in map-based cloning of agriculturally-important genes.