FERTILE TRANSGENIC WHEAT FROM MICROPROJECTILE BOMBARDMENT OF SCUTELLAR TISSUE

A reproducible transformation system for hexaploid wheat was developed based bombardment of scutellar tissue embryos. Particle bombardment w as carried out using a PDS 1000/He gun. Plant material was bombarded w ith the plasmid pDB1 containing the beta-glucuronidase gene (uidA) und er the control of the actin-1 promoter of rice, and the selectable mar ker gene bar (phosphinothricin acetyltransferase) under the control of the CaMV 35S promoter. Selection was carried out using the herbicide Basta (Glufosinateammonium). From a total number of 1050 bombarded imm ature embryos, in seven independent transformation experiments, 59 pla nts could be regenerated. Putative transformants were screened for enz yme activity by the histochemical GUS assay using cut leaf material an d by spraying the whole plants with an aqueous solution of the herbici de Basta. Twelve regenerants survived Basta spraying and showed GUS-ac tivity. Southern-blot analysis indicated the presence of introduced fo reign genes in the genomic DNA of the transformants and both marker ge nes were present in all plants analysed. To date, four plants have bee n grown to maturity and set seed. Histochemically stained pollen grain s showed a 1:1 segregation of the uidA gene in all plants tested. A 3: 1 segregation of the introduced genes was demonstrated by enzyme activ ity tests and Southern blot analysis of R(1) plants.