Paleoenvironmental and paleoclimatic variations around Lake Van (Eastern Turkey) recorded by sedimentary source specific biomarkers 250–130 ka (MIS7 and MIS6)

Guillemot, Typhaine; Stockhecke, Mona; Bechtel, Achim; Ladd, S. Nemiah; Nelson, Daniel B.; Schubert, Carsten J.

doi:10.1016/j.quascirev.2019.105997

Cited by 6 publications

(1 citation statement)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Reconstructing δ 2 H values of precipitation is useful for learning about past changes in temperature, moisture transit pathways, and precipitation intensity, depending on location (Bowen et al ., 2019), and sedimentary leaf wax δ 2 H values are increasingly used for this purpose (e.g. Tierney et al ., 2017; Bhattacharya et al ., 2018; Guillemot et al ., 2019; Hinojosa et al ., 2019). Although used as a proxy for precipitation δ 2 H values, leaf wax δ 2 H values are also influenced by 2 H‐enrichment of leaf water, as well as biosynthetic hydrogen isotope fractionation relative to leaf water (Sachse et al ., 2012).…”

Section: Introductionmentioning

confidence: 99%

Metabolic exchange between pathways for isoprenoid synthesis and implications for biosynthetic hydrogen isotope fractionation

et al. 2021

View full text Add to dashboard Cite

 Hydrogen isotope ratios of plant lipids are used for paleoclimate reconstruction, but are influenced by both source water and biosynthetic processes. Measuring 2 H/ 1 H ratios of multiple compounds produced by different pathways could allow these effects to be separated, but hydrogen isotope fractionations during isoprenoid biosynthesis remain poorly constrained.  To investigate how hydrogen isotope fractionation during isoprenoid biosynthesis is influenced by molecular exchange between the cytosolic and plastidial production pathways, we paired position specific 13 C-pyruvate labeling with hydrogen isotope measurements of lipids in Pachira aquatica saplings.  We find that acetogenic compounds primarily incorporated carbon from 13 C2-pyruvate, whereas isoprenoids incorporated 13 C1-and 13 C2-pyruvate equally. This indicates that cytosolic pyruvate is primarily introduced into plastidial isoprenoids via glyceraldehyde 3phosphate and that plastidial isoprenoid intermediates are incorporated into cytosolic isoprenoids. Likely due to the large differences in hydrogen isotope fractionation between plastidial and cytosolic isoprenoid pathways, sterols from P. aquatica are at least 50 ‰ less 2 H-enriched relative to phytol than sterols in other plants.  These results provide the first experimental evidence that incorporation of plastidial intermediates reduces 2 H/ 1 H ratios of sterols. This suggests that relative offsets between the 2 H/ 1 H ratios of sterols and phytol can trace exchange between the two isoprenoid synthesis pathways.

show abstract