Biochemical pathways in seed oil synthesis

The seed oil and starch content of soybean are significantly different from that of chickpea. However, there are limited studies on its molecular mechanisms. To address this issue, we conducted integrated transcriptomic and bioinformatics analyses for species-specific genes and acyl-lipid-, starch-, and carbon metabolism-related genes. Among seven expressional patterns of soybean-specific genes, four were highly expressed at the middle- and late oil accumulation stages; these genes significantly enriched fatty acid synthesis and carbon metabolism, and along with common acetyl CoA carboxylase (ACCase) highly expressed at soybean middle seed development stage, common starch-degrading enzyme beta-amylase-5 (BAM5) was highly expressed at soybean early seed development stage and oil synthesis-related genes ACCase, KAS, KAR, ACP, and long-chain acyl-CoA synthetase (LACS) were co-expressed with WRI1, which may result in high seed oil content and low seed starch content in soybean. The common ADP-glucose pyrophosphorylase (AGPase) was highly expressed at chickpea middle seed development stage, along with more starch biosynthesis genes co-expressed with four-transcription-factor homologous genes in chickpea than in soybean, and the common WRI1 was not co-expressed with oil synthesis genes in chickpea, which may result in high seed starch content and low seed oil content in chickpea. The above results may be used to improve chickpea seed oil content in two ways. One is to edit CaWRI1 to co-express with oil synthesis-related genes, which may increase carbon metabolites flowing to oil synthesis, and another is to increase the expression levels of miRNA159 and miRNA319 to inhibit the expression of MYB33, which may downregulate starch synthesis-related genes, making more carbon metabolites flow into oil synthesis. Our study will provide a basis for future breeding efforts to increase the oil content of chickpea seeds.

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Effect of soluble sugar content in silique wall on seed oil accumulation during the seed-filling stage in Brassica napus

Crop and Pasture Science ◽

10.1071/cp17392 ◽

2018 ◽

Vol 69 (12) ◽

pp. 1251

Author(s):

Fei Ni ◽

Jiahuan Liu ◽

Jing Zhang ◽

Mohammad Nauman Khan ◽

Tao Luo ◽

...

Keyword(s):

Seed Yield ◽

Seed Oil ◽

Sugar Content ◽

Soluble Sugar ◽

C:N Ratio ◽

Oil Accumulation ◽

N Application ◽

Soluble Sugar Content ◽

Oil Synthesis ◽

Oil Concentration

Soluble sugar content in silique wall and seeds of rapeseed (Brassica napus L.) has significant effects on seed oil formation and accumulation. We studied the relationship between soluble sugar content in B. napus seeds and silique wall and oil concentration under field conditions in two cropping seasons, and examined changes in soluble sugar content in seeds and silique wall under different nitrogen (N) levels. Two commercialised Chinese rapeseed varieties, HZ9 and HZ62, with high seed yield and different N responses were used. Our results indicated that carbon (C):N ratio and soluble sugar content in silique wall had the greater effect on seed oil concentration. When C:N ratio and soluble sugar content in silique wall were within 5–15% and 10–25%, respectively, plants had relatively well coordinated C and N metabolism, facilitating oil accumulation. During 25–35 days of silique development, when C:N ratio and soluble sugar content in silique wall were within 10–15 and 15–25%, respectively, oil synthesis was fastest; the highest accumulation rate was 3.8% per day. When they were each <5%, seeds tended to mature, and oil synthesis gradually decreased, ceased or degraded. During the early stage of silique development, if C:N ratio and soluble sugar content in silique wall were >15% and 30%, there was no apparent tendency for oil accumulation, probably because of adverse environmental conditions. When N application increased from 0 to 270kg ha–1, final oil concentration in seeds decreased by 0.024%. In summary, C:N ratio and soluble sugar content in silique wall are important in regulating seed oil concentration, whereas excessive N application significantly reduced seed oil concentration. Therefore, appropriate reduction of N application would save resources, provide environment benefits and increase rapeseed oil production with no substantial reduction in seed yield, through coordinated seed yield and oil concentration.

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Integument-Specific Transcriptional Regulation in the Mid-Stage of Flax Seed Development Influences the Release of Mucilage and the Seed Oil Content

Cells ◽

10.3390/cells10102677 ◽

2021 ◽

Vol 10 (10) ◽

pp. 2677

Author(s):

Fabien Miart ◽

Jean-Xavier Fontaine ◽

Gaëlle Mongelard ◽

Christopher Wattier ◽

Michelle Lequart ◽

...

Keyword(s):

Seed Development ◽

Seed Coat ◽

Seed Oil ◽

Recombinant Inbred Lines ◽

Secretory Cells ◽

Seed Oil Content ◽

Linum Usitatissimum L ◽

Oil Synthesis ◽

Spatio Temporal ◽

Seed Coat Mucilage

Flax (Linum usitatissimum L.) seed oil, which accumulates in the embryo, and mucilage, which is synthesized in the seed coat, are of great economic importance for food, pharmaceutical as well as chemical industries. Theories on the link between oil and mucilage production in seeds consist in the spatio-temporal competition of both compounds for photosynthates during the very early stages of seed development. In this study, we demonstrate a positive relationship between seed oil production and seed coat mucilage extrusion in the agronomic model, flax. Three recombinant inbred lines were selected for low, medium and high mucilage and seed oil contents. Metabolite and transcript profiling (1H NMR and DNA oligo-microarrays) was performed on the seeds during seed development. These analyses showed main changes in the seed coat transcriptome during the mid-phase of seed development (25 Days Post-Anthesis), once the mucilage biosynthesis and modification processes are thought to be finished. These transcriptome changes comprised genes that are putatively involved in mucilage chemical modification and oil synthesis, as well as gibberellic acid (GA) metabolism. The results of this integrative biology approach suggest that transcriptional regulations of seed oil and fatty acid (FA) metabolism could occur in the seed coat during the mid-stage of seed development, once the seed coat carbon supplies have been used for mucilage biosynthesis and mechanochemical properties of the mucilage secretory cells.

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INTEGUMENT-SPECIFIC TRANSCRIPTIONAL REGULATION IN THE MID-STAGE OF FLAX SEED DEVELOPMENT INFLUENCES THE RELEASE OF MUCILAGE AND THE SEED OIL CONTENT

10.1101/2021.09.09.459608 ◽

2021 ◽

Author(s):

Fabien Miart ◽

Jean-Xavier Fontaine ◽

Gaëlle Mongelard ◽

Christopher Wattier ◽

Michelle Lequart-Pillon ◽

...

Keyword(s):

Seed Development ◽

Seed Coat ◽

Seed Oil ◽

Recombinant Inbred Lines ◽

Secretory Cells ◽

Seed Oil Content ◽

Oil Synthesis ◽

Great Economic Importance ◽

Spatio Temporal ◽

Seed Coat Mucilage

ABSTRACTFlax (Linum usitatissimum L.) seed oil, which accumulates in the embryo, and mucilage, which is synthesized in the seed coat, are of great economic importance for food, pharmaceutical as well as chemical industries. Theories on the link between oil and mucilage production in seeds consist in the spatio-temporal competition of both compounds for photosynthates during the very early stages of seed development. In this study, we demonstrate a positive relationship between seed oil production and seed coat mucilage extrusion in the agronomic model, flax. Three recombinant inbred lines were selected for low, medium and high mucilage and seed oil contents. Metabolite and transcript profiling (1H NMR and DNA oligo-microarrays) was performed on the seeds during seed development. These analyses showed main changes in the seed coat transcriptome during the mid-phase of seed development (25 Days Post-Anthesis), once the mucilage biosynthesis and modification processes are thought to be finished. These transcriptome changes comprised genes that are putatively involved in mucilage chemical modification and oil synthesis, as well as gibberellic acid (GA) metabolism. The results of these integrative biology approach, suggest that transcriptional regulations of seed oil and fatty acid (FA) metabolism could occur in the seed coat during the mid-stage of seed development, once the seed coat carbon supplies have been used for mucilage biosynthesis and mechanochemical properties of the mucilage secretory cells.

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In SilicoIdentification and Comparative Genomics of Candidate Genes Involved in Biosynthesis and Accumulation of Seed Oil in Plants

Comparative and Functional Genomics ◽

10.1155/2012/914843 ◽

2012 ◽

Vol 2012 ◽

pp. 1-14 ◽

Cited By ~ 18

Author(s):

Arti Sharma ◽

Rajinder Singh Chauhan

Keyword(s):

Fatty Acids ◽

Comparative Genomics ◽

Plant Species ◽

Seed Oil ◽

Structure And Function ◽

Oil Bodies ◽

Oil Accumulation ◽

Oil Synthesis ◽

Total Oil ◽

And Function

Genes involved in fatty acids biosynthesis, modification and oil body formation are expected to be conserved in structure and function in different plant species. However, significant differences in the composition of fatty acids and total oil contents in seeds have been observed in different plant species. Comparative genomics was performed on 261 genes involved in fatty acids biosynthesis, TAG synthesis, and oil bodies formation in Arabidopsis,Brassica rapa, castor bean and soybean.In silicoexpression analysis revealed that stearoyl desaturase, FatB, FAD2, oleosin and DGAT are highly abundant in seeds, thereby considered as ideal candidates for mining of favorable alleles in natural population. Gene structure analysis for major genes, ACCase, FatA, FatB, FAD2, FAD3 and DGAT, which are known to play crucial role in oil synthesis revealed that there are uncommon variations (SNPs and INDELs) which lead to varying content and composition of fatty acids in seed oil. The predicted variations can provide good targets for seed oil QTL identification, understanding the molecular mechanism of seed oil accumulation, and genetic modification to enhance seed oil yield in plants.

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FAX2 Mediates Fatty Acid Export from Plastids in Developing Arabidopsis Seeds

Plant and Cell Physiology ◽

10.1093/pcp/pcz117 ◽

2019 ◽

Vol 60 (10) ◽

pp. 2231-2242 ◽

Cited By ~ 3

Author(s):

Yinshuai Tian ◽

Xueyan Lv ◽

Guilan Xie ◽

Linghui Wang ◽

Tingwei Dai ◽

...

Keyword(s):

Target Gene ◽

Seed Oil ◽

Mutant Cell ◽

Lipid Production ◽

Building Blocks ◽

Wild Type ◽

Oil Accumulation ◽

Oil Synthesis ◽

Family Protein ◽

Synthesis Activity

Abstract Vegetable oils are mainly stored in the form of triacylglycerol (TAG) in oilseeds. Fatty acids (FAs), one of the building blocks for TAG assembly, are synthesized in plastids and then exported to the endoplasmic reticulum for storage oil synthesis. A recent study demonstrated that the export of FAs from plastids was mediated by a FAX (FA export) family protein. However, the significance of FAs export from plastid during seed oil accumulation has not been investigated. In this study, we found that FAX2 was highly expressed in developing Arabidopsis seeds and the expression level was consistent with FAs synthesis activity. FAX2 mutant seeds showed an approximately 18% reduction of lipid levels compared with wild-type seeds. By contrast, overexpression of FAX2 enhanced seed lipid accumulation by up to 30%. The FAs export activity of FAX2 was confirmed by yeast mutant cell complementation analysis. Our results showed that FAX2 could interact with other proteins to facilitate FAs transport. Taken together, these results indicate that FAX2-mediated FA export from plastids is important for seed oil accumulation, and that FAX2 can be used as a target gene for increasing lipid production in oilseeds.

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