ARS | Publication request: MOSAIC CUCUMBER LINE MSC16 CARRIES MITOCHONDRIAL GENOME REARRANGEMENTS AND SHOWS INCREASED ALTERNATIVE OXIDASE (AOX) EXPRESSION

Submitted to: Polish Genetics Society Conference
Publication Type: Abstract Only
Publication Acceptance Date: May 15, 2004
Publication Date: June 30, 2004
Citation: Bartoszewski, G., Malepszy, S., Havey, M.J. 2004. Mosaic cucumber line msc16 carries mitochondrial genome rearrangements and shows increased alternative oxidase (aox) expression. Polish Genetics Society Conference.

Technical Abstract: The mosaic cucumber line MSC16 phenotype shows slower growth and mosaic type of leaf spots (Malepszy et al 1996) and is associated with complex mitochondrial rearrangements causing DNA deletions and duplications (Bartoszewski et al 2004). Alternative oxidase (AOX), a nuclear-encoded component of the plant respiratory chain, functions to prevent the oxygen free radicals formation. AOX is differentially expressed during normal plant development and in response to stresses. AOX expression is influenced by mitochondrial genome rearrangements (Karpowa et al., 2002). Using degenerated primers, we cloned and sequenced conserved regions of the cucumber Aox gene. Southern-blot hybridization revealed a single band suggesting that there is one copy or small Aox multigene family in the cucumber genome. Aox transcript level was increased in leaves and male flowers of MSC16 cucumber as compared with control inbred line B. Immunoblotting of total or mitochondrial proteins with anti-AOX monoclonal antibody (kindly provided by Dr. Thomas Elton, Univ. of Nebraska) showed clearly that AOX is present in leaves and flowers of MSC16 and is almost not delectable in control line B. Our experiments indicate that AOX expression is increased in MSC16 cucumber suggesting that this line is experiencing continuous oxidative stress and AOX expression is probably post-translationally regulated.