Molecular and Pathway Controls on Biogenic Volatile Organic Compound Emissions

Leaf anatomy, BVOC emission and CO2exchange of arctic plants following snow addition and summer warming

“…Delayed plant activity was particularly evident for B. nana, for which P N was considerably reduced (24 % across the campaigns) in the snow addition plots, especially at the beginning of the measurement period. Reduction in P N would also indicate a reduction in BVOCs from de novo synthesis (Loreto and Schnitzler, 2010;Li and Sharkey, 2013). The negative correlation between P N and SQTs suggests that the increased SQT emission from B. nana was not from de novo synthesis but from stored compounds.…”

“…In general, direct short-term temperature responses in BVOC emissions are caused by accelerated biochemical reaction rates, higher compound volatility and increased cellular diffusion rates. As the emission of BVOCs directly released from de novo synthesis is tightly linked to photosynthetic carbon metabolism (Loreto and Schnitzler, 2010;Li and Sharkey, 2013), even for species with specialized storage structures (Ghirardo et al, 2010), changes in photosynthetic rates caused by warming (Oechel and Billings, 1992;Larcher, 2003) could furthermore lead to altered BVOC emissions. Indirect temperature effects, such as possible lengthening of the growing season, vegetation biomass increase and changes in vegetation composition, could also increase total BVOC emissions (Laothawornkitkul et al, 2009).…”

Bisphosphonate Inhibitors Reveal a Large Elasticity of Plastidic Isoprenoid Synthesis Pathway in Isoprene-Emitting Hybrid Aspen

“…They are formed by two pathways in plants, the mevalonate (MVA) pathway in the cytosol (Gershenzon and Croteau, 1993) and the 1-deoxy-D-xylulose 5-phosphate (DXP)/2-Cmethyl-D-erythritol 4-phosphate (MEP) pathway in plastids (Gershenzon and Croteau, 1993;Jomaa et al, 1999;Li and Sharkey, 2013b). The MVA pathway is primarily responsible for the synthesis of sesquiterpenes (C15), triterpenes (C30) including brassinosteroids, and even larger molecules such as dolichols (Bick and Lange, 2003;Li and Sharkey, 2013b;Rajabi Memari et al, 2013;Rosenkranz and Schnitzler, 2013). The DXP/MEP pathway is responsible for the synthesis of the simplest isoprenoids, isoprene and 2-methyl-3-buten-2-ol (C5), monoterpenes (C10), diterpenes (C20) including gibberellins and phytol residue of chlorophylls, and tetraterpenes (C40) including carotenoids (Rodríguez-Concepción and Boronat, 2002;Roberts, 2007).…”

“…Isoprene-emitting species constitute an exciting model system where a very large DXP/MEP pathway flux goes to isoprene synthesis under physiological conditions (Li and Sharkey, 2013b;Sharkey et al, 2013). In isoprene-emitting species, there is a concomitant use of the primary substrate DMADP between the plastidic synthesis of isoprene and isoprenoids with a larger molecular size, such as phytol residue of chlorophyll (C20) and carotenoids (C40; Ghirardo et al, 2014;Rasulov et al, 2014), and different from nonemitting species, isoprene emitters seem to support a much larger pool of DMADP without the onset of feedback inhibition Wright et al, 2014).…”

“…In addition, more hydrophobic zoledronate likely penetrates the membranes more feasibly than alendronate (Russell et al, 2008). The first reaction of the DXP/MEP pathway, condensation of pyruvate and glyceraldehyde 3-phosphate resulting in formation of DXP, is catalyzed by DXP synthase, a thiamin diphosphate (TDP)-dependent transketolase (Rohmer et al, 1996;Li and Sharkey, 2013b , without any signs of feedback inhibition (Rasulov et al, 2009a(Rasulov et al, , 2011(Rasulov et al, , 2014Li et al, 2011;Ghirardo et al, 2014). This suggests that relatively high DMADP concentrations are needed for an operational feedback at least in vivo (i.e.…”