Temperature Acclimation of the Picoalga Ostreococcus tauri Triggers Early Fatty-Acid Variations and Involves a Plastidial ω3-Desaturase

Degraeve-Guilbault, Charlotte; Pankasem, Nattiwong; Gueirrero, Maurean; Lemoigne, Cécile; Domergue, Frédéric; Kotajima, Tomonori; Suzuki, Iwane; Joubès, Jérôme; Corellou, Florence

doi:10.3389/fpls.2021.639330

Cited by 13 publications

(14 citation statements)

References 78 publications

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“…The relative percentage of the PUFA 16:4, 18:3, and 18:4 were highest at a cultivation temperature of 20°C, and decreased with higher temperatures (30 and 35°C) (Figures 6a–c, 4a–c and 7a‐c). It is well known that many organisms raise their degree of FA unsaturation at lower temperatures in order to maintain the cell membrane fluidity (Alfonso et al, 2001; Collados et al, 2006; de Mendoza & Cronan Jr, 1983; Degraeve‐Guilbault et al, 2021; Patterson, 1970). Our data suggest that these temperature‐triggered changes of FA unsaturation in A. obliquus are performed by the ratio change of the FA 16:4, 18:3, and 18:4 and lower desaturated FA.…”

Section: Discussionmentioning

confidence: 99%

“…Beside the lipid content, also the degree of saturation and the FA composition can be influenced by the microalgae cultivation conditions. One of the underlying mechanisms of temperature adaptation in plants, microorganisms, and green algae is the modification of the degree of FA saturation to regulate the cell membrane fluidity (Alfonso et al, 2001; Collados et al, 2006; de Mendoza & Cronan Jr, 1983; Degraeve‐Guilbault et al, 2021; Patterson, 1970).…”

Section: Introductionmentioning

confidence: 99%

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Growth and fatty acid composition of Acutodesmus obliquus under different light spectra and temperatures

Helamieh

Gebhardt²,

Reich

et al. 2021

Lipids

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The combined impact of temperature and light spectra on the fatty acid (FA) composition in microalgae has been sparsely investigated. The aim of this study was to investigate the interactions of light and temperature on the FA composition in Acutodesmus obliquus. For this purpose, A. obliquus was cultivated with different temperatures (20, 30, and 35 C), as well as broad light spectra (blue, green, and red light). Growth and FA composition were monitored daily. Microalgal FA were extracted, and a qualitative characterization was done by gas chromatography coupled with electron impact ionization mass spectrometry (GC-EI/MS). Compared to red light, green and blue light caused a higher percentage of the polyunsaturated fatty acids (PUFA) 16:4, 18:3, and 18:4, at all temperatures. The highest total percentage of these PUFA were observed at the lowest cultivation temperature and blue and green light. These data imply that a combination of lower temperatures and blue-green light (450-550 nm) positively influences the activity of specific FA-desaturases in A. obliquus. Additionally, a lower 16:1 trans/cis ratio was observed upon green and blue light treatment and lower cultivation temperatures. Remarkably, green light treatment resulted in a comparably high growth under all tested conditions. Therefore, a higher content of green light, compared to blue light might additionally lead to a higher biomass concentration. Microalgae cultivation with low temperatures and green light might therefore result in a suitable FA composition for the food industry and a comparably high biomass production.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Growth and fatty acid composition of Acutodesmus obliquus under different light spectra and temperatures

Helamieh

Gebhardt²,

Reich

et al. 2021

Lipids

View full text Add to dashboard Cite

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“…The low temperature was chosen to maximize the FA‐unsaturation. Microalgae raise the PUFA content with lowered environmental temperatures to maintain the fluidity of cell membranes (Degraeve‐Guilbault et al, 2021; Patterson, 1970). However, the used cultivation temperature is lower than the optimum temperature of this species, which is around 30°C (Hindersin et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

“…For example, phytohormones and the pretreatment of microalgae with low‐dose atmospheric plasma can increase growth and FA production (Almarashi et al, 2020; Esakkimuthu et al, 2020). It is also well‐known that the cultivation temperature greatly impacts the FA composition of microalgae, whereby lower cultivation temperatures are related to a higher PUFA concentration and a higher degree of FA unsaturation (Degraeve‐Guilbault et al, 2021; Patterson, 1970). Another abiotic parameter that impacts the FA composition is the intensity and spectral composition of light (Hultberg et al, 2014; Nzayisenga et al, 2020; Shu et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Blue‐green light is required for a maximized fatty acid unsaturation and pigment concentration in the microalga Acutodesmus obliquus

Helamieh

Reich

Bory

et al. 2022

Lipids

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Blue‐green light is known to maximize the degree of fatty acid (FA) unsaturation in microalgae. However, knowledge on the particular waveband responsible for this stimulation of FA desaturation and its impact on the pigment composition in microalgae remains limited. In this study, Acutodesmus obliquus was cultivated for 96 h at 15°C with different light spectra (380–700 nm, 470–700 nm, 520–700 nm, 600–700 nm, and dark controls). Growth was monitored daily, and qualitative characterization of the microalgal FA composition was achieved via gas chromatography coupled with electron impact ionization mass spectrometry (GC‐EI/MS). Additionally, a quantitative analysis of microalgal pigments was performed using high‐performance liquid chromatography with diode array detection (HPLC‐DAD). Spectra that included wavelengths between 470 and 520 nm led to a significantly higher percentage of the polyunsaturated fatty acids (PUFA) 18:3 and 16:4, compared to all other light conditions. However, no significant differences between the red light cultivations and the heterotrophic dark controls were observed for the FA 18:3 and 16:4. These results indicate, that exclusively the blue‐green light waveband between 470 and 520 nm is responsible for a maximized FA unsaturation in A. obliquus. Furthermore, the growth and production of pigments were impaired if blue‐green light (380–520 nm) was absent in the light spectrum. This knowledge can contribute to achieving a suitable microalgal pigment and FA composition for industrial purposes and must be considered in spectrally selective microalgae cultivation systems.

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“…Previously, Degraeve-Guilbault et al ( 2017); Degraeve-Guilbault et al ( 2021) provided a comprehensive study of the glycerolipidome and validated this species as a model for related picoeukaryotes. O. tauri lipids showed unique characteristics that combined traits from green and chromalveolate lineages (Degraeve-Guilbault et al, 2017;Degraeve-Guilbault et al, 2021). Ostreococcus presents a single APC-type transporter (Amino acid/ polyamine transporter, NCBI Sequence: XP_003083160.2) orthologous to AOC5/6 (plant cationic amino acid transporters).…”

Section: Discussionmentioning

confidence: 99%

Arginine as the sole nitrogen source for Ostreococcus tauri growth: Insights on nitric oxide synthase enzyme

et al. 2022

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IntroductionPhotosynthetic organisms respond to nitrogen (N) deprivation with the slowdown of photosynthesis and electron transport resulting in the balance the carbon (C)/N ratio. Under this extreme condition, organisms trigger complex mechanisms to keep growing using different N sources and recycling N containing molecules. In particular, phytoplankton are able to uptake L-arginine (L-Arg) as an organic N source. L-Arg can be assimilated mainly by the arginase, arginine deimidase, arginine decarboxylase or L-amino oxidase pathways.ResultsWe analyzed the effect of different N sources on the growth of the green algae Ostreococcus tauri. N starvation caused an inhibition of culture growth and a decrease in chlorophyll content. The addition of L-Arg to an N-deprived medium promotes a sustained growth rate of O. tauri culture and the increase of chlorophyll levels. The transcript level of genes involved in N uptake and metabolism were increased in N-starved condition while the addition of L-Arg as the sole N source reduced their induction. Since the O. tauri genome lacks the classical pathways to metabolize L-Arg, another enzyme/s may be responsible for L-Arg catabolism. Previously, we characterized the nitric oxide synthase (NOS) enzyme from O. tauri (OtNOS) which oxidizes L-Arg producing nitric oxide (NO) and citrulline. The NOS inhibitor L-NAME blocks the effect promoted by L-Arg on N-deprived O. tauri growth. Besides, NO level increased in O. tauri cells growing in L-Arg containing medium, suggesting the participation of OtNOS enzyme in L-Arg metabolism during N starvation.DiscussionOur hypothesis suggests that, after NOS-dependent Arg degradation, non-enzymatic oxidation of NO produces N oxides (mainly NO2-) that are re-incorporated to the N primary metabolism. As expected, N deprivation increases the lipid content in Ostreococcus. The addition of L-Arg or NO2- as the sole N sources showed a similar increase in lipid content to N deprivation. In summary, our results demonstrate that L-Arg is able to function as N source in Ostreococcus. The evidences on an alternative pathway of N supply and metabolism in a photosynthetic microorganism are discussed. These results could also allow the development of biotechnological tools for increasing lipid production for industry.

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Temperature Acclimation of the Picoalga Ostreococcus tauri Triggers Early Fatty-Acid Variations and Involves a Plastidial ω3-Desaturase

Cited by 13 publications

References 78 publications

Growth and fatty acid composition of Acutodesmus obliquus under different light spectra and temperatures

Growth and fatty acid composition of Acutodesmus obliquus under different light spectra and temperatures

Blue‐green light is required for a maximized fatty acid unsaturation and pigment concentration in the microalga Acutodesmus obliquus

Arginine as the sole nitrogen source for Ostreococcus tauri growth: Insights on nitric oxide synthase enzyme

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