Plant Isoprenoid Biology team, Institut de Biologie Moléculaire des Plantes, University of Strasbourg
Hubert Schaller (pictured), Pascal Heitzler, Thomas Bach, Anne Berna, Andréa Hemmerlin, Florence Ploetze, Pierre Mercier
We are plant scientists with expertise in analytical chemistry, biochemistry, cell biology, genetics and microbiology who develop multiple approaches to provide a refined understanding of critical roles of specific sterols and steroids in biological processes. Our team is hosted in a CNRS research unit of the Strasbourg University campus, where we interact with collaborators at the Chemistry Institute, and develop international collaborations. Our objective is to decipher the essential role of plant-typical sterols at the cellular and molecular levels. Plant cells use a sterol pathway that is peculiar compared with that of other eukaryotes. They transform 2,3-oxidosqualene into cycloartenol and other 9β,19-cyclopropylsterols which are further converted into Δ5-sterols, and beyond into brassinosteroids, or sterol conjugates such as glucosides or fatty acid esters.1-3 Genetic studies in Arabidopsis thaliana and in some other species have shown that disruption in sterol homeostasis lead to dramatic morphogenetic inhibitions throughout the plant life cycle, reminiscent of human sterolosis syndrome.4-7 A key feature is the chemical diversity of plant sterol profiles mainly due to side chain modification enzymes among which sterol methyltransferases allow the production of a mixture of 24-alkyl-D5-sterols.8 Cholesterol is ubiquitous but a low abundant plant sterol except in solanaceous species where it is the precursor of steroidal alkaloids.9 The significance of a highly conserved but complicated biosynthetic route leading from 9β,19-cyclopropylsterols to Δ5-sterols 10-11,12 and the role of these products in the control of the plant cell division, growth and development represents a new and current trend of our work in sterol biology.13
Key papers related to ENOR
1 Schaller H. Sterol and Steroid Biosynthesis and Metabolism in Plants and Microorganisms. In: Comprehensive Natural Products II Chemistry and Biology; Mander, L., Lui, H.-W, Eds.; Elsevier: Oxford, (2010); Vol. No.1, pp 755 - 787.
2 Debolt S et al. Mutations in UDP-Glucose:sterol glucosyltransferase in Arabidopsis cause transparent testa phenotype and suberization defect in seeds (2009) Plant Physiol. 151:78-87.
3 Bouvier-Navé P et al. Involvement of the phospholipid sterol acyltransferase1 in plant sterol homeostasis and leaf senescence (2010) Plant Physiol. 152:107-19.
4 Brodersen P et al. Isoprenoid biosynthesis is required for miRNA function and affects membrane association of ARGONAUTE 1 in Arabidopsis (2012) Proc. Natl. Acad. Sci. USA 109:1778-1783.
5 Silvestro D et al. Plant sterol metabolism. Δ7-sterol-C5-desaturase (STE1/DWARF7), Δ5,7-sterol-Δ7-reductase (DWARF5) and Δ24-sterol-Δ24-reductase (DIMINUTO/DWARF1) show multiple subcellular localizations in Arabidopsis thaliana (Heynh) L.(2013) PLoS One 8(2):e56429.
6 Qian P et al. Sterols are required for cell-fate commitment and maintenance of the stomatal lineage in Arabidopsis (2013) Plant J. 74:1029-44.
7 Le Hir R et al. ABCG9, ABCG11 and ABCG14 ABC transporters are required for vascular development in Arabidopsis (2012) Plant J 76:811-24.
8 Schaeffer A et al. The ratio of campesterol to sitosterol that modulates growth in Arabidopsis is controlled by STEROL METHYL TRANSFERASE 2 :1 (2001) Plant J 25:1-12.
9 Sonawane PD et al. Plant cholesterol biosynthetic pathway overlaps with phytosterol metabolism (2016) Nat Plants 3:16205-16217.
10 Babiychuk E et al. Allelic mutant series reveal distinct functions for Arabidopsis cycloartenol synthase 1 in cell viability and plastid biogenesis (2008) Proc. Natl. Acad. Sci. USA 105:3163-3168.
11 Gas-Pascual E et al. Plant oxidosqualene metabolism : cycloartenol synthase-dependent biosynthesis in Nicotiana benthamiana (2014) PLos One 9(10):e109156.
12 Villette C et al. Plant Sterol Diversity in Pollen from Angiosperms (2015) Lipids 50:749-60.
13 Nakamoto M et al. Diversification of sterol methyltransferase enzymes in plants and a role for β-sitosterol in oriented cell plate formation and polarized growth (2015) Plant J 84:860-74.