title: The Mosaic Mutants of Cucumber: A Method to Produce Knock-Downs of Mitochondrial Transcripts.
abstract: Cytoplasmic effects on plant performance are well-documented and result from the intimate interaction between organellar and nuclear gene products. In plants, deletions, mutations, or chimerism of mitochondrial genes are often associated with deleterious phenotypes, as well as economically important traits such as cytoplasmic male sterility used to produce hybrid seed. Presently, genetic analyses of mitochondrial function and nuclear interactions are limited because there is no method to efficiently produce mitochondrial mutants. Cucumber (Cucumis sativus L.) possesses unique attributes useful for organellar genetics, including differential transmission of the three plant genomes (maternal for plastid, paternal for mitochondrial, and bi-parental for nuclear), a relatively large mitochondrial DNA in which recombination among repetitive motifs produces rearrangements, and the existence of strongly mosaic (MSC) paternally transmitted phenotypes that appear after passage of wild-type plants through cell cultures and possess unique rearrangements in the mitochondrial DNA. We sequenced the mitochondrial DNA from three independently produced MSC lines and revealed under-represented regions and reduced transcription of mitochondrial genes carried in these regions relative to the wild-type parental line. Mass spectrometry and Western blots did not corroborate transcriptional differences in the mitochondrial proteome of the MSC mutant lines, indicating that post-transcriptional events, such as protein longevity, may compensate for reduced transcription in MSC mitochondria. Our results support cucumber as a model system to produce transcriptional "knock-downs" of mitochondrial genes useful to study mitochondrial responses and nuclear interactions important for plant performance.
authors: Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706.
authors: Angel R
authors: AR
authors: Del Valle-Echevarria
authors: Faculty of Horticulture, Agricultural University of Krakow, Al. 29 Listopada 54, 31-425 Krakow, Poland.
authors: Agnieszka
authors: A
authors: Kiełkowska
authors: Department of Plant Genetics, Breeding and Biotechnology, Faculty of Horticulture, Biotechnology and Landscape Architecture, Warsaw University of Life Sciences, ul. Nowoursynowska 159, 02-776 Warsaw, Poland.
authors: Grzegorz
authors: G
authors: Bartoszewski
authors: Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706 USDA Agricultural Research Service, University of Wisconsin, Madison, Wisconsin 53706 mjhavey@wisc.edu.
authors: Michael J
authors: MJ
authors: Havey
mesh_terms: D015153:Blotting, Western; D002467:Cell Nucleus / Q000235:genetics; D002853:Chromatography, Liquid; D018553:Cucumis sativus / Q000235:genetics*; D056915:DNA Copy Number Variations / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D055785:Gene Knockdown Techniques / Q000379:methods*; D050259:Genes, Mitochondrial; D017343:Genes, Plant; D013058:Mass Spectrometry; D008928:Mitochondria / Q000235:genetics* / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism; D009030:Mosaicism; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D010940:Plant Proteins / Q000378:metabolism; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D004272:DNA, Mitochondrial; D024101:Mitochondrial Proteins; D010940:Plant Proteins; D012333:RNA, Messenger
keywords: Cucumis sativus; mitochondrial mutant; mitochondrial transcript; plant mitochondria