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In the heat of the night – alternative pathway respiration drives thermogenesis in Philodendron bipinnatifidum

Journal Article


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Abstract


  • • Philodendron bipinnatifidum inflorescences heat up to 42C and thermoregulate.

    We investigated whether they generate heat via the cytochrome oxidase

    pathway uncoupled by uncoupling proteins (pUCPs), or the alternative oxidase

    (AOX).

    • Contribution of AOX and pUCPs to heating in fertile (FM) and sterile (SM) male

    florets was determined using a combination of oxygen isotope discrimination, protein

    and substrate analyses.

    • Both FM and SM florets thermoregulated independently for up to 30 h ex

    planta. In both floret types, AOX contributed > 90% of respiratory flux during

    peak heating. The AOX protein increased fivefold with the onset of thermogenesis

    in both floret types, whereas pUCP remained low throughout development. These

    data indicate that AOX is primarily responsible for heating, despite FM and SM

    florets potentially using different substrates, carbohydrates or lipids, respectively.

    Measurements of discrimination between O2 isotopes in strongly respiring SM florets

    were affected by diffusion; however, this diffusional limitation was largely

    overcome using elevated O2.

    • The first in vivo respiratory flux measurements in an arum show AOX contributes

    the bulk of heating in P. bipinnatifidum. Fine-scale regulation of AOX activity

    is post-translational. We also demonstrate that elevated O2 can aid measurement

    of respiratory pathway fluxes in dense tissues.

Authors


  •   Miller, Bec E. (external author)
  •   Grant, Nicole M. (external author)
  •   Giles, L (external author)
  •   Ribas-Carbo, Miquel (external author)
  •   Berry, Joseph A. (external author)
  •   Watling, Jennifer R. (external author)
  •   Robinson, Sharon

Publication Date


  • 2011

Citation


  • Miller, R. E., Grant, N. M., Giles, L., Ribas-Carbo, M., Berry, J., Watling, J. R. & Robinson, S. A. (2011). In the heat of the night – alternative pathway respiration drives thermogenesis in Philodendron bipinnatifidum. New Phytologist, 189 (4), 1013-1026.

Scopus Eid


  • 2-s2.0-79551558051

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=8584&context=scipapers

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/5241

Has Global Citation Frequency


Number Of Pages


  • 13

Start Page


  • 1013

End Page


  • 1026

Volume


  • 189

Issue


  • 4

Abstract


  • • Philodendron bipinnatifidum inflorescences heat up to 42C and thermoregulate.

    We investigated whether they generate heat via the cytochrome oxidase

    pathway uncoupled by uncoupling proteins (pUCPs), or the alternative oxidase

    (AOX).

    • Contribution of AOX and pUCPs to heating in fertile (FM) and sterile (SM) male

    florets was determined using a combination of oxygen isotope discrimination, protein

    and substrate analyses.

    • Both FM and SM florets thermoregulated independently for up to 30 h ex

    planta. In both floret types, AOX contributed > 90% of respiratory flux during

    peak heating. The AOX protein increased fivefold with the onset of thermogenesis

    in both floret types, whereas pUCP remained low throughout development. These

    data indicate that AOX is primarily responsible for heating, despite FM and SM

    florets potentially using different substrates, carbohydrates or lipids, respectively.

    Measurements of discrimination between O2 isotopes in strongly respiring SM florets

    were affected by diffusion; however, this diffusional limitation was largely

    overcome using elevated O2.

    • The first in vivo respiratory flux measurements in an arum show AOX contributes

    the bulk of heating in P. bipinnatifidum. Fine-scale regulation of AOX activity

    is post-translational. We also demonstrate that elevated O2 can aid measurement

    of respiratory pathway fluxes in dense tissues.

Authors


  •   Miller, Bec E. (external author)
  •   Grant, Nicole M. (external author)
  •   Giles, L (external author)
  •   Ribas-Carbo, Miquel (external author)
  •   Berry, Joseph A. (external author)
  •   Watling, Jennifer R. (external author)
  •   Robinson, Sharon

Publication Date


  • 2011

Citation


  • Miller, R. E., Grant, N. M., Giles, L., Ribas-Carbo, M., Berry, J., Watling, J. R. & Robinson, S. A. (2011). In the heat of the night – alternative pathway respiration drives thermogenesis in Philodendron bipinnatifidum. New Phytologist, 189 (4), 1013-1026.

Scopus Eid


  • 2-s2.0-79551558051

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=8584&context=scipapers

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/5241

Has Global Citation Frequency


Number Of Pages


  • 13

Start Page


  • 1013

End Page


  • 1026

Volume


  • 189

Issue


  • 4