Differential Activation of Partially Redundant Δ9 Stearoyl-ACP Desaturase Genes Is Critical for Omega-9 Monounsaturated Fatty Acid Biosynthesis During Seed Development in Arabidopsis - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue The Plant cell Année : 2020

Differential Activation of Partially Redundant Δ9 Stearoyl-ACP Desaturase Genes Is Critical for Omega-9 Monounsaturated Fatty Acid Biosynthesis During Seed Development in Arabidopsis

Résumé

The spatiotemporal pattern of deposition, final amount, and relative abundance of oleic acid (cis-omega-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 Delta 9 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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Dates et versions

hal-02996686 , version 1 (03-09-2021)

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Citer

Sami Kazaz, Guillaume Barthole, Frédéric Domergue, Hasna Ettaki, Alexandra To, et al.. Differential Activation of Partially Redundant Δ9 Stearoyl-ACP Desaturase Genes Is Critical for Omega-9 Monounsaturated Fatty Acid Biosynthesis During Seed Development in Arabidopsis. The Plant cell, 2020, 32 (11), pp.3613-3637. ⟨10.1105/tpc.20.00554⟩. ⟨hal-02996686⟩
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