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This article in TPG

  1. Vol. 4 No. 3, p. 283-299
    Received: May 27, 2011

    * Corresponding author(s): rpwise@iastate.edu


Rf8-Mediated T-urf13 Transcript Accumulation Coincides with a Pentatricopeptide Repeat Cluster on Maize Chromosome 2L

  1. Julie Meyer,
  2. Deqing Pei and
  3. Roger P. Wise 
  1. J. Meyer, D. Pei, and R.P. Wise, Interdepartmental Genetics Program, Iowa State Univ., Ames, IA 50011; and Department of Plant Pathology and Microbiology, Iowa State Univ., Ames, IA 50011; J. Meyer, present address: Regulatory Sciences Product Characterization Center, Monsanto, St. Louis, MO 63167; D. Pei, present address: Dep. of Biostatistics, St. Jude's Children Research Hospital, Memphis, TN 38105; R.P. Wise, USDA-ARS, Crop and Insect Genetics, Genomics, and Informatics Research Unit, Iowa State Univ., Ames, IA 50011


Cytoplasmic male sterility (CMS) is a maternally inherited inability to produce functional pollen. In Texas (T)-cytoplasm maize (Zea mays L.), CMS results from the action of the URF13 mitochondrial pore-forming protein encoded by the unique T-urf13 mitochondrial gene. Full or partial restoration of fertility to T-cytoplasm maize is mediated by the Rf2a nuclear gene in combination with one of three other genes: Rf1, Rf8, or Rf*. Rf2a encodes a mitochondrial aldehyde dehydrogenase whereas Rf1, Rf8, and Rf* are associated with the accumulation of distinctive T-urf13 mitochondrial transcripts. Rf8-associated RNA processing activity was mapped to a 4.55-Mbp region on chromosome 2L that contains 10 pentatricopeptide repeat (PPR) encoding genes in the B73 5b.60 genome assembly. Genetic linkage analysis also indicated that Rf* is positioned within this PPR cluster as well as Rf3, which restores USDA (S)-cytoplasm maize. Partially male-fertile plants segregated for the presence or absence of the Rf8-associated T-urf13 1.42- and 0.42-kbp transcripts, indicating that the RNA processing event associated with these transcripts is not necessary for anther exsertion. In addition, a statistically significant delay in flowering was observed between partially male-fertile and mostly male-fertile plants. Taken together, these new results indicate that Rf8-mediated male fertility is under the control of more than one nuclear locus.

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