i. Maize genetics, transposable element systems and their use in induction of mutations and transposon tagging.
My laboratory is genetically dissecting the sex determination pathways in maize. Both the male tassel and female ear begin development as bisexual flowers. However, during the developmental process, the female primordial in the tassel abort by a process of cell death while the male primordial in the ear abort by cell arrest. We are currently investigating the role of a number of tasselseed mutations, mutations in which the female primordial develop in the tassel. We are also in the process of cloning the silkless gene and examining its role in sex determination. In mutant forms of this gene, no female primordial develop in the ear, resulting in complete female sterility. Current research centers on the study of a transposable element system that was activated in a descendant of a virus infected plant. The element is a member of the spm family; mutation frequencies at different loci in plants containing this element range from 10-5 to -3. We are interested in determining whether these mutations are due to the insertion of spm elements or to other transposable elements that have been activated in this stock. If the mutations are due to the activity of a single family of elements, it may be possible to develop a new transposon tagging system for the cloning of genes.
Jhennan Xu, Xianghe Yan, Steve Maurais, Huihua Fu, David G. O’Brien, John Mottinger, and Hugo K. Dooner. Jittery, a Mutator Distant Relative with a Paradoxical Mobile Behavior: Excision without Reinsertion. The Plant Cell 16:1105-1114, 2004.