Delta 5 Fatty Acid Desaturase Upregulates the Synthesis of Polyunsaturated Fatty Acids in the Marine Diatom <i>Phaeodactylum tricornutum</i>

Peng, Kun-Tao; Zheng, Cun-Ni; Xue, Jiao; Xiao-yan, Chen; Yang, Wei‐Dong; Liu, Jie‐Sheng; Bai, Weibin; Li, Hongye

doi:10.1021/jf5031086

Cited by 99 publications

(62 citation statements)

References 9 publications

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“…∆5 desaturase, which is encoded by Fad1 , adds a double bond at the fifth carbon-carbon bond from the carboxylic acid end in FAs such as dihomo-gamma-linoleic acid (DGLA, 20:3 n -6) and ETA (20:4 n -3) to produce arachidonic acid (ARA, 20:4 n -6) and EPA, respectively 29 . Consistently, overexpression of a putative ER-localised FAD1 significantly enhanced the accumulation of both monounsaturated and polyunsaturated fatty acids in the marine diatom Phaeodactylum tricornutum 30 . DGAT catalyses the last step of TAG synthesis from DAG and acyl-CoA 31 , and includes DGAT-1 and DGAT-2 32 .…”

Section: Resultsmentioning

confidence: 60%

Transcriptional Regulation of Cellulose Biosynthesis during the Early Phase of Nitrogen Deprivation in Nannochloropsis salina

Jeong

Nam

Hwangbo

et al. 2017

Sci Rep

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Microalgal photosynthesis provides energy and carbon-containing precursors for the biosynthesis of storage carbohydrates such as starch, chrysolaminarin, lipids, and cell wall components. Under mild nitrogen deficiency (N−), some Nannochloropsis species accumulate lipid by augmenting cytosolic fatty acid biosynthesis with a temporary increase in laminarin. Accordingly, biosynthesis of the cellulose-rich cell wall should change in response to N− stress because this biosynthetic pathway begins with utilisation of the hexose phosphate pool supplied from photosynthesis. However, few studies have characterised microalgal cell wall metabolism, including oleaginous Nannochloropsis sp. microalgae subjected to nitrogen deficiency. Here, we investigated N-induced changes in cellulose biosynthesis in N. salina. We observed that N− induced cell wall thickening, concurrently increased the transcript levels of genes coding for UDPG pyrophosphorylase and cellulose synthases, and increased cellulose content. Nannochloropsis salina cells with thickened cell wall were more susceptible to mechanical stress such as bead-beating and sonication, implicating cellulose metabolism as a potential target for cost-effective microalgal cell disruption.

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Section: Resultsmentioning

confidence: 60%

Transcriptional Regulation of Cellulose Biosynthesis during the Early Phase of Nitrogen Deprivation in Nannochloropsis salina

Jeong

Nam

Hwangbo

et al. 2017

Sci Rep

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“…1), as has been surmised in P. tricornutum (Aroa and Yamada 1994). Continuing clarification of these pathways will facilitate metabolic engineering efforts (Domergue et al 2002;2003;Peng et al 2014). During silicon starvation in diatoms, TAG accumulation is induced (Roessler 1988;Yu et al 2009).…”

Section: Discussionmentioning

confidence: 99%

“…The increased accumulation of DHA relative to EPA regardless of which elongase is overexpressed, as well as under silicon limitation, is consistent with preferential accumulation of the end product of the pathway. Other manipulations and combined manipulations could improve carbon flux into EPA and DHA synthesis or alter the ratio of EPA to DHA, for example, overexpression of a delta 5 desaturase in P. tricornutum resulted in increased neutral lipid and EPA (Peng et al 2014).…”

Section: Discussionmentioning

confidence: 99%

Enhancing LC-PUFA production in Thalassiosira pseudonana by overexpressing the endogenous fatty acid elongase genes

Cook

Hildebrand

2015

J Appl Phycol

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The health beneficial omega-3 long-chain polyunsaturated fatty acids (LC-PUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) are naturally synthesized by diatoms through consecutive steps of fatty acid elongase and desaturase enzymes. In Thalassiosira pseudonana, these fatty acids constitute about 10-20 % of the total fatty acids, with EPA accumulation being five to ten times higher than DHA. In order to identify the subcellular localization of enzymes in the pathway of LC-PUFA biosynthesis in T. pseudonana and to manipulate the production of EPA and DHA, we generated constructs for overexpressing each of the T. pseudonana long-chain fatty acid elongase genes. Full-length proteins were fused to GFP, and transgenic lines were generated. In addition, overexpressed native proteins with no GFP fusion were tested. The subcellular localization of each elongase protein was determined. We then examined the total amount of lipids and analyzed the fatty acid profile in each of the transgenic lines compared to wild type. Lines with overexpressed elongases showed an increase of up to 1.4-fold in EPA and up to 4.5-fold in DHA, and the type of fatty acid that was increased (EPA vs. DHA) depended on the type of elongase that was overexpressed. This data informs future metabolic engineering approaches to further improve EPA and DHA content in diatoms.

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“…When the Δ5-desaturase gene PtD5b was cloned and overexpressed in P. tricornutum , fatty acid composition was altered [123]. The neutral lipid content determined by Nile red fluorescence staining indicated an increase in transgenic cells.…”

Section: Bioengineering In Diatomsmentioning

confidence: 99%

Modulation of lipid biosynthesis by stress in diatoms

Sayanova

Mimouni

Ulmann

et al. 2017

Phil. Trans. R. Soc. B

111

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Diatoms are responsible for up to 40% of the carbon fixation in our oceans. The fixed carbon is moved through carbon metabolism towards the synthesis of organic molecules that are consumed through interlocking foodwebs, and this process is strongly impacted by the abiotic environment. However, it has become evident that diatoms can be used as ‘platform’ organisms for the production of high valuable bio-products such as lipids, pigments and carbohydrates where stress conditions can be used to direct carbon metabolism towards the commercial production of these compounds. In the first section of this review, some aspects of carbon metabolism in diatoms and how it is impacted by environmental factors are briefly described. The second section is focused on the biosynthesis of lipids and in particular omega-3 long-chain polyunsaturated fatty acids and how low temperature stress impacts on the production of these compounds. In a third section, we review the recent advances in bioengineering for lipid production. Finally, we discuss new perspectives for designing strains for the sustainable production of high-value lipids.This article is part of the themed issue ‘The peculiar carbon metabolism in diatoms’.

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Delta 5 Fatty Acid Desaturase Upregulates the Synthesis of Polyunsaturated Fatty Acids in the Marine Diatom Phaeodactylum tricornutum

Cited by 99 publications

References 9 publications

Transcriptional Regulation of Cellulose Biosynthesis during the Early Phase of Nitrogen Deprivation in Nannochloropsis salina

Transcriptional Regulation of Cellulose Biosynthesis during the Early Phase of Nitrogen Deprivation in Nannochloropsis salina

Enhancing LC-PUFA production in Thalassiosira pseudonana by overexpressing the endogenous fatty acid elongase genes

Modulation of lipid biosynthesis by stress in diatoms

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