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Kazaz S, Barthole G, Domergue F, Ettaki H, To A, Vasselon D, De Vos D, Belcram K, Lepiniec L, Baud S. Differential Activation of Partially Redundant Δ9 Stearoyl-ACP Desaturase Genes Is Critical for Omega-9 Monounsaturated Fatty Acid Biosynthesis During Seed Development in Arabidopsis. Plant Cell 2020; 32:3613-3637. [PMID: 32958563 PMCID: PMC7610281 DOI: 10.1105/tpc.20.00554] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/04/2020] [Accepted: 09/16/2020] [Indexed: 05/20/2023]
Abstract
The spatiotemporal pattern of deposition, final amount, and relative abundance of oleic acid (cis-ω-9 C18:1) and its derivatives in the different lipid fractions of the seed of Arabidopsis (Arabidopsis thaliana) indicates that omega-9 monoenes are synthesized at high rates in this organ. Accordingly, we observed that four Δ9 stearoyl-ACP desaturase (SAD)-coding genes (FATTY ACID BIOSYNTHESIS2 [FAB2], ACYL-ACYL CARRIER PROTEIN5 [AAD5], AAD1, and AAD6) are transcriptionally induced in seeds. We established that the three most highly expressed ones are directly activated by the WRINKLED1 transcription factor. We characterized a collection of 30 simple, double, triple, and quadruple mutants affected in SAD-coding genes and thereby revealed the functions of these desaturases throughout seed development. Production of oleic acid by FAB2 and AAD5 appears to be critical at the onset of embryo morphogenesis. Double homozygous plants from crossing fab2 and aad5 could never be obtained, and further investigations revealed that the double mutation results in the arrest of embryo development before the globular stage. During later stages of seed development, these two SADs, together with AAD1, participate in the elaboration of the embryonic cuticle, a barrier essential for embryo-endosperm separation during the phase of invasive embryo growth through the endosperm. This study also demonstrates that the four desaturases redundantly contribute to storage lipid production during the maturation phase.
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Affiliation(s)
- Sami Kazaz
- Institut Jean-Pierre Bourgin, INRAE, CNRS, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Guillaume Barthole
- Institut Jean-Pierre Bourgin, INRAE, CNRS, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Frédéric Domergue
- Université de Bordeaux, Laboratoire de Biogenèse Membranaire, UMR 5200, 33882 Villenave d'Ornon, France
- CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, 33882 Villenave d'Ornon, France
| | - Hasna Ettaki
- Institut Jean-Pierre Bourgin, INRAE, CNRS, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Alexandra To
- Institut Jean-Pierre Bourgin, INRAE, CNRS, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Damien Vasselon
- Institut Jean-Pierre Bourgin, INRAE, CNRS, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Delphine De Vos
- Institut Jean-Pierre Bourgin, INRAE, CNRS, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Katia Belcram
- Institut Jean-Pierre Bourgin, INRAE, CNRS, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Loïc Lepiniec
- Institut Jean-Pierre Bourgin, INRAE, CNRS, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
| | - Sébastien Baud
- Institut Jean-Pierre Bourgin, INRAE, CNRS, AgroParisTech, Université Paris-Saclay, 78000 Versailles, France
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