title: A 13-kilodalton maize mitochondrial protein in E. coli confers sensitivity to Bipolaris maydis toxin.
abstract: The Texas male-sterile cytoplasm (cms-T) of maize carries the cytoplasmically inherited trait of male sterility. Mitochondria isolated from cms-T maize are specifically sensitive to a toxin (BmT-toxin) produced by the fungal pathogen Bipolaris maydis, race T, and the carbamate insecticide methomyl. A mitochondrial gene unique to cms-T maize, which produces a 13-kilodalton polypeptide associated with cytoplasmic male sterility, was expressed in Escherichia coli. After addition of BmT-toxin or methomyl, inhibition of whole cell respiration and swelling of spheroplasts were observed in Escherichia coli cultures producing the novel mitochondrial protein; these effects are similar to those observed with isolated cms-T mitochondria. The amino-terminal region of the 13-kilodalton polypeptide appears to be essential for proper interaction with the BmT-toxin and methomyl. These results implicate the 13-kilodalton polypeptide in conferring toxin sensitivity to mitochondria of cms-T maize.
authors.affiliation: Department of Crop Science, North Carolina State University, Raleigh 27695.
authors.forename: R E
authors.initials: RE
authors.lastname: Dewey
authors.forename: J N
authors.initials: JN
authors.lastname: Siedow
authors.forename: D H
authors.initials: DH
authors.lastname: Timothy
authors.forename: C S
authors.initials: CS
authors.lastname: Levings
mesh_terms: D001426:Bacterial Proteins / Q000494:pharmacology*; D003001:Cloning, Molecular; D003062:Codon; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D008724:Methomyl / Q000494:pharmacology; D008928:Mitochondria / Q000032:analysis*; D008970:Molecular Weight; D009183:Mycotoxins / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects; D010940:Plant Proteins / Q000235:genetics* / Q000502:physiology; D010944:Plants / Q000032:analysis / Q000187:drug effects / Q000235:genetics*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D003313:Zea mays
chemical_list: D001426:Bacterial Proteins; D003062:Codon; D009183:Mycotoxins; D010940:Plant Proteins; D008724:Methomyl; D004024:Dicyclohexylcarbodiimide