Retention of tumor markers in F1 progeny plants from in vitro induced octopine and nopaline tumor tissues.

Tumorous tobacco shoots have been derived from callus tissues produced by Agrobacterium tumefaciens--induced transformation of tobacco protoplasts and by fusion of normal protoplasts with those from crown gall tumors. The continued presence of T-DNA sequences in shoots is directly demonstrated by Southern blotting and is also revealed by the presence of the tumor markers octopine and nopaline. When grafted onto normal tobacco plants, both octopine- and nopaline-type shoots (including those from somatic hybrids) produced flowers and set seed. Germination of these seeds gave F1 progeny that showed retention of morphological markers of their parental shoots, and one seedling retained the ability to synthesize nopaline. The data demonstrate that T-DNA markers can be retained during meiosis and are expressed in F1 plants.