Restoration of fertility by antisense RNA in genetically engineered male sterile tobacco plants
Thomas Schmülling
1
, Horst Röhrig
2
, Silke Pilz
2
, Richard Walden
2
, and Jeff Schell
2
Mol Gen Genet 237: 385-394.
1
UniversitΣt Tⁿbingen, Lehrstuhl fⁿr Allgemeine Genetik, Auf der Morgenstelle 28, D-72076 Tⁿbingen, Germany
2
Max-Planck-Institut fⁿr Züchtungsforschung, Carl-von-LinnΘ-Weg 10, D-50829 Köln, Germany
Summary
Transgenic tobacco plants (
Nicotiana tabacum
L.) expressing the
rolC
gene of
Agrobacterium rhizogenes
under the transcriptional control of the 35S RNA promoter are male sterile. When these plants are genetically crossed with others containing the rolC gene linked in antisense to the 35S RNA promoter, hybrid progeny display restoration of male fertility. Moreover, hybrid progeny are revertant for other features of the
rolC
phenotype such as restoration of plant height, leaf pigment content and female fertility. The level of restoration of the characteristics of untransformed tobacco appeared to be independent of steady state level of antisense RNA. Addition of six transcriptional enhancer sequences upstream of the 35S transcriptional start region in the antisense construct led to a higher steady state level of antisense RNA when compared with a promoter linked to a single enhancer sequence. However no significant difference was observed in the level of ablation of
rolC
phenotype in the progeny of crosses with either one or six transcriptional enhancers linked to the antisense rolC gene. Antisense constructs comprising only 189 bp of the
rolC
5┤ coding region appeared less efficient in
rolC
phenotype ablation when compared with those covering the whole
rolC
coding region as well as its 3┤ untranslated region. Furthermore, results from light controlled rolC gene expression indicate that microsporogenesis is sensitive to
rolC
gene action during early stages of flower development.
