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United States Department of Agriculture

Agricultural Research Service

Title: Unraveling the Maize Rf1 Genomic Region

Authors
item Wise, Roger
item Pei, Deqing - IOWA STATE UNIVERSITY
item Gobelman Werner, Karin

Submitted to: Plant Molecular Biology International Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 20, 2000
Publication Date: N/A

Technical Abstract: T-cytoplasm maize (cms-T) has been developed as a model to study the genetic and molecular mechanisms underlying male sterility and fertility restoration. Male sterility in cms-T results from the function of the T- cytoplasm specific, mitochondrial gene, T-urf13. Nuclear restorer (Rf) genes suppress CMS-associated male sterility. In cms-T, restoration of fertility is mediated by one of three (Rf1, Rf8, or Rf*) nuclear restorers in combination with the Rf2 restorer. Rf2 encodes a mitochondrial aldehyde dehydrogenase, whereas, Rf1, Rf8, and Rf* each mediate discrete T-urf13 transcript processing events. To isolate the Rf1 gene, a Mutator transposon tagging approach was used to generate rf1-m insertion mutants. Cosegregating amplified fragments were identified via AFLP transposon display (AIMS) from three independent rf1-m families. Analysis of candidate cDNAs indicates that the rf1 locus is very large. Therefore, to determine the physical features of this locus, a BAC contig spanning the rf1genomic region is being assembled. Two B73 BAC libraries were screened using tightly linked RFLPs, AIMS fragments, and low-copy probes designed from the rf1 candidate cDNA. BAC clones were grouped into contigs by restriction-digest fingerprints and hybridization analysis. BAC-end sequence data were used to design "overgos" for further library screening. The development of a DNA contig spanning rf1 will facilitate the complete characterization of this interesting region of the maize genome. Research supported by USDA-NRI/CGP grant 99-01334.

Last Modified: 12/27/2014