De novo post-illumination monoterpene burst in Quercus ilex (holm oak)

K. G. Srikanta Dani, Giovanni Marino, Cosimo Taiti, Stefano Mancuso, Brian J. Atwell, Francesco Loreto, Mauro Centritto

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Explicit proof for de novo origin of a rare post-illumination monoterpene burst and its consistency under low O₂, shows interaction of photorespiration, photosynthesis, and isoprenoid biosynthesis during light–dark transitions. Quercus ilex L (holm oak) constitutively emits foliar monoterpenes in an isoprene-like fashion via the methyl erythritol phosphate (MEP) pathway located in chloroplasts. Isoprene-emitting plants are known to exhibit post-illumination isoprene burst, a transient emission of isoprene in darkness. An analogous post-illumination monoterpene burst (PiMB) had remained elusive and is reported here for the first time in Q. ilex. Using ¹³CO₂ labelling, we show that PiMB is made from freshly fixed carbon. PiMB is rare at ambient (20%) O₂, absent at high (50%) O₂, and becomes consistent in leaves exposed to low (2%) O₂. PiMB is stronger and occurs earlier at higher temperatures. We also show that primary and secondary post-illumination CO₂bursts (PiCO₂B) are sensitive to O₂ in Q. ilex. The primary photorespiratory PiCO₂B is absent under both ambient and low O₂, but is induced under high (>50%) O₂, while the secondary PiCO₂B (of unknown origin) is absent under ambient, but present at low and high O₂. We propose that post-illumination recycling of photorespired CO₂ competes with the MEP pathway for photosynthetic carbon and energy, making PiMB rare under ambient O₂ and absent at high O₂. PiMB becomes consistent when photorespiration is suppressed in Q. ilex.
Original languageEnglish
Pages (from-to)459-465
Number of pages7
JournalPlanta
Volume245
Issue number2
DOIs
Publication statusPublished - Feb 2017

Keywords

  • ¹³CO₂ labelling
  • light-dark transition
  • MEP pathway
  • monoterpene emission
  • post-illumination bursts
  • photosynthesis
  • photorespiratory CO₂ recycling

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