Articles
Brassinosteroid-induced modulation of sphingolipid long-chain base composition and gene expression during early olive-fruit development
Article number
1297_77
Pages
589 – 596
Language
English
Abstract
Sphingolipids are abundant membrane components and signaling molecules in various aspects of plant development.
However, the role of sphingolipids in early fleshy-fruit growth has been rarely investigated.
In this study, we first investigated the temporal changes in sphingolipid long-chain base (LCB) content, composition, and gene expression that occurred during flower opening and early fruit development in olive (Olea europaea L. ‘Picual’). Moreover, the interaction between sphingolipid and the plant hormone, brassinosteroid (BR), during the early fruit development was also explored.
For this, BR levels were manipulated through the application of exogenous BRs (24-epibrassinolide, EBR) or a BR biosynthesis inhibitor (brassinazole, Brz) and their effects on early fruit development, sphingolipid LCB content, and gene expression was examined in olive fruit at 14 days post-anthesis (DPA). We here show that sphingolipid with C-4 hydroxylation and Δ8 desaturation with a preference for (E)-isomer formation are quantitatively the most important sphingolipids in olive reproductive organs.
In this work, the total LCB amount significantly decreased at the anthesis stage, but olivesphingosine-1-phosphate lyase (OeSPL) gene was expressed exclusively in flower and upregulated during the anthesis, revealing an association with the d18:1(8E) accumulation.
However, the LCB content increased in parallel with the upregulation of the expression of genes for key sphingolipid biosynthetic and LCB modification enzymes during early fruit development in olive.
Likewise, we found that EBR exogenously applied in olive tree significantly accelerated the fruit growth rate associated with reduced levels of sphingolipid LCB content and gene expression in olive fruit after 7 and 14 days of treatment, whereas Brz slowed the fruit growth rate and boosted the sphingolipid LCB content and gene expression during early growth.
Thus, our data indicate that endogenous sphingolipid LCB and gene-expression levels are intricately controlled during early fruit development in olive and also suggest a possible link between BR, the sphingolipid content/gene expression, and early fruit development.
However, the role of sphingolipids in early fleshy-fruit growth has been rarely investigated.
In this study, we first investigated the temporal changes in sphingolipid long-chain base (LCB) content, composition, and gene expression that occurred during flower opening and early fruit development in olive (Olea europaea L. ‘Picual’). Moreover, the interaction between sphingolipid and the plant hormone, brassinosteroid (BR), during the early fruit development was also explored.
For this, BR levels were manipulated through the application of exogenous BRs (24-epibrassinolide, EBR) or a BR biosynthesis inhibitor (brassinazole, Brz) and their effects on early fruit development, sphingolipid LCB content, and gene expression was examined in olive fruit at 14 days post-anthesis (DPA). We here show that sphingolipid with C-4 hydroxylation and Δ8 desaturation with a preference for (E)-isomer formation are quantitatively the most important sphingolipids in olive reproductive organs.
In this work, the total LCB amount significantly decreased at the anthesis stage, but olivesphingosine-1-phosphate lyase (OeSPL) gene was expressed exclusively in flower and upregulated during the anthesis, revealing an association with the d18:1(8E) accumulation.
However, the LCB content increased in parallel with the upregulation of the expression of genes for key sphingolipid biosynthetic and LCB modification enzymes during early fruit development in olive.
Likewise, we found that EBR exogenously applied in olive tree significantly accelerated the fruit growth rate associated with reduced levels of sphingolipid LCB content and gene expression in olive fruit after 7 and 14 days of treatment, whereas Brz slowed the fruit growth rate and boosted the sphingolipid LCB content and gene expression during early growth.
Thus, our data indicate that endogenous sphingolipid LCB and gene-expression levels are intricately controlled during early fruit development in olive and also suggest a possible link between BR, the sphingolipid content/gene expression, and early fruit development.
Authors
J. Corbacho, C. Inês, M.C. Camarero, B. Briegas, M.A. Paredes, J. Labrador, M. Gallardo, A.M. Cordeiro, M.C. Gomez-Jimenez
Keywords
brassinosteroid, early fruit growth, sphingosine kinase, serine palmitoyltransferase, sphingosine-1-phosphate lyase
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