A raison d’être for two distinct pathways in the early steps of plant isoprenoid biosynthesis?

Modeling of Dolichol Mass Spectra Isotopic Envelopes as a Tool to Monitor Isoprenoid Biosynthesis

“…Various intermediates (e.g. IPP, DMAPP, GPP, FPP, and oligoprenyl diphosphates; Hemmerlin et al, 2012;May et al, 2013) were shown to be translocated between these compartments. Moreover, a complex bidirectional transfer of precursors was postulated earlier (Skorupinska-Tudek et al, 2008) as well as in the current model (Fig.…”

“…The contribution of the MEP pathway increased significantly (reaching 100%) exclusively for the dominating Dols, while for long-chain Dols, the relative input of the MEP and MVA pathways remained unchanged, suggesting divergent sites of synthesis for dominating and long-chain Dols. The analysis of numerically modeled Dol mass spectra is a novel method to follow modulation of the concomitant activity of isoprenoid-generating pathways in plant cells; additionally, it suggests an exchange of isoprenoid intermediates between plastids and peroxisomes.Isopentenyl diphosphate (IPP), the building block of isoprenoids, the most numerous class of secondary metabolites, is derived in plants from two pathways operating in parallel: the cytoplasmic mevalonate (MVA) and the plastidic methylerythritol phosphate (MEP) pathways (Rohmer, 1999;Pulido et al, 2012).Analysis of over 130 isoprenoids has shown that, in angiosperms under standard growth conditions, carotenoids and chlorophyll phytyl chains on the one hand and phytosterols on the other are made nearly exclusively via a single pathway (MEP and MVA, respectively), while numerous other isoprenoids, including dolichols (Dols; Skorupinska-Tudek et al, 2008), are of mixed origin (Hemmerlin et al, 2012).The cooperation of the two pathways (often called cross talk) is considered essential for plant adaptive responses to biotic and abiotic stresses. Consequently, their relative contributions to the formation of IPP are modulated, and the expression of particular genes of the MVA and MEP pathways is frequently correlated with stress (pathogen attack, elicitation, wounding, etc.…”

“…Analysis of over 130 isoprenoids has shown that, in angiosperms under standard growth conditions, carotenoids and chlorophyll phytyl chains on the one hand and phytosterols on the other are made nearly exclusively via a single pathway (MEP and MVA, respectively), while numerous other isoprenoids, including dolichols (Dols; Skorupinska-Tudek et al, 2008), are of mixed origin (Hemmerlin et al, 2012).…”

“…Consequently, their relative contributions to the formation of IPP are modulated, and the expression of particular genes of the MVA and MEP pathways is frequently correlated with stress (pathogen attack, elicitation, wounding, etc. ; Hemmerlin et al, 2012) or plant development (Opitz et al, 2014). Interestingly, the effect of stress on the regulation of the MEP-MVA balance has so far been analyzed only qualitatively.…”

<sup>13</sup>C labelling study of constitutive and stress-induced terpenoide missions from Norway spruce and Scots pine

“…During the past decade, studies of plant terpenoid emissions have been focused on the MEP pathway with neglecting the role of the MVA pathway (Hemmerlin et al, 2012). So far, empirical algorithms (Guenther et al, 1993;Guenther et al, 1995;Guenther et al, 2006;Guenther et al, 2012) as well as process-based models (Niinemets et al, 1999;Arneth et al, 2007) 20 have mainly focused on constitutive isoprene and monoterpenes, which mainly originate from the MEP pathway.…”