Stable transformation of sorghum cell cultures after bombardment with DNA-coated microprojectiles

Cells from a suspension culture of Sorghum vulgare (sorghum) have been transformed to either hygromycin or kanamycin resistance following uptake of pBC1 or pNGI plasmids, respectively, introduced on DNA-coated high velocity microprojectiles. Hygromycin- and kanamycin-resistant transformants contained hygromycin B phosphotransferase- and neomycin phosphotransferasehybridizing restriction fragments of the expected size, respectively. A second introduced, but unselected for, reporter uidA gene which encodes ß-glucuronidase activity was also detected by DNA gel blot analysis in these transformants and shown to be expressed at low levels in two of the ten transformants analyzed. Transcripts from the introduced foreign genes accumulated to detectable levels in only these two transformants, both of which had a high copy number of genes integrated into their genome. This report further establishes the biolistic method as a useful route for delivery of DNA into the difficult-to-transform monocotyledonous plant species and represents the first stable transformation of this agronomically-important cereal grain.