Mitochondrial transcript processing and restoration of male fertility in T-cytoplasm maize.
Cytoplasmic male sterility (CMS) systems have been useful in the production of hybrid seed in a number of crops. The Texas or T-cytoplasmic male-sterile (cms-T) system was used extensively in the 1960s to eliminate the need for hand detasseling in hybrid maize production. As a consequence of the 1970 epidemic of southern corn leaf blight, cms-T is no longer widely used commercially. However, it has been developed as a model system to study the genetic and molecular mechanisms underlying male sterility and fertility restoration. Male sterility in T-cytoplasm maize results from the action of a T-cytoplasm-specific mitochondrial gene, T-urf13. Full (or partial) fertility restoration of T-cytoplasm maize is mediated by the Rf2 nuclear restorer in combination with one of three other restorers: Rf1, Rf8, or Rf*. Rf2 encodes a protein highly similar to mitochondrial aldehyde dehydrogenases; Rf1, Rf8, and Rf* each mediate discrete T-urf13 mitochondrial transcript processing events. To test the functionality of Rf1, Rf8, or Rf*, a T-cytoplasm transformation system is under development. AFLP bulk-segregant analysis has been used to identify DNA markers closely linked to the Rf8 locus. These tools will provide a foundation for determining mechanisms of nuclear-directed mitochondrial RNA processing and fertility restoration.
Wise
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USDA-ARS, Department of Plant Pathology, Iowa State University, Ames 50011-1020, USA. rpwise@iastate.edu
Gobelman-Werner
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Pei
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Dill
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Schnable
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D000483:Alleles; D001483:Base Sequence; D004251:DNA Transposable Elements; D018076:DNA, Complementary; D004272:DNA, Mitochondrial / Q000235:genetics*; D018745:Genome, Plant; D009154:Mutation; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid; D003313:Zea mays / Q000235:genetics* / Q000502:physiology
D004251:DNA Transposable Elements; D018076:DNA, Complementary; D004272:DNA, Mitochondrial; D012333:RNA, Messenger