MAINTENANCE OF A PLANT-LINE CONTAINING AN ANTISENSE GENE AND SILENCING OF THE TARGET GENE FOLLOWING SEXUAL CROSSES

Doubly transformed tobacco plants containing both sense and antisense chloramphenicol aceltyltransferase (CAT) genes and showing > 90% inhibition of CAT gene expression were previously produced. One such plant was back-crossed with untransformed tobacco, and progeny were selected in which the CAT and anti-CAT genes were segregated. Progency containing the CAT gene but lacking the antisense construct showed fully restored CAT activity whereas those containing only the antisense genes expressed no CAT activity. The latter were stably maintained through two generations. Recombination of the sense and antisense genes by sexual crossing resulted in efficient antisense RNA-mediated inactivation of the CAT gene. © 1990.