Transcriptome and Gene Expression Analysis of an Oleaginous Diatom Under Different Salinity Conditions

Cheng, Ruo-Lin; Feng, Jia; Zhang, Bingxin; Huang, Yun; Cheng, Jun; Zhang, Chuan‐Xi

doi:10.1007/s12155-013-9360-1

Cited by 58 publications

(63 citation statements)

References 53 publications

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“…In response to salt stress, all subunits of the chloroplastic ACCase were considerably up-regulated (over eightfold), suggesting that the chloroplastic ACCase represents a committed enzyme controlling the biosynthesis of fatty acids in C. zofingiensis. The salt-induced expression of ACCase has also been reported in some other algae including Chlamydomonas [26,39,40], Chlorella [41], and Nitzschia [42]. Obviously, in C. zofingiensis the transcriptional expression of ACCase subunits correlated well with each other (Additional file 8: Data S6), supporting their coordinated regulation as stated by previous reports [43,44].…”

Section: Salt Stress Promotes Fatty Acid Synthesis While Attenuating supporting

confidence: 84%

Novel insights into salinity-induced lipogenesis and carotenogenesis in the oleaginous astaxanthin-producing alga Chromochloris zofingiensis: a multi-omics study

Mao

Zhang

Wang

et al. 2020

Biotechnol Biofuels

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Background: Chromochloris zofingiensis, a freshwater alga capable of synthesizing both triacylglycerol (TAG) and astaxanthin, has been receiving increasing attention as a leading candidate producer. While the mechanism of oleaginousness and/or carotenogenesis has been studied under such induction conditions as nitrogen deprivation, high light and glucose feeding, it remains to be elucidated in response to salt stress, a condition critical for reducing freshwater footprint during algal production processes. Results:Firstly, the effect of salt concentrations on growth, lipids and carotenoids was examined for C. zofingiensis, and 0.2 M NaCl demonstrated to be the optimal salt concentration for maximizing both TAG and astaxanthin production. Then, the time-resolved lipid and carotenoid profiles and comparative transcriptomes and metabolomes were generated in response to the optimized salt concentration for congruent analysis. A global response was triggered in C. zofingiensis allowing acclimation to salt stress, including photosynthesis impairment, ROS build-up, protein turnover, starch degradation, and TAG and astaxanthin accumulation. The lipid metabolism involved a set of stimulated biological pathways that contributed to carbon precursors, energy and reductant molecules, pushing and pulling power, and storage sink for TAG accumulation. On the other hand, salt stress suppressed lutein biosynthesis, stimulated astaxanthin biosynthesis (mainly via ketolation), yet had little effect on total carotenoid flux, leading to astaxanthin accumulation at the expense of lutein. Astaxanthin was predominantly esterified and accumulated in a well-coordinated manner with TAG, pointing to the presence of common regulators and potential communication for the two compounds. Furthermore, the comparison between salt stress and nitrogen deprivation conditions revealed distinctions in TAG and astaxanthin biosynthesis as well as critical genes with engineering potential. Conclusions:Our multi-omics data and integrated analysis shed light on the salt acclimation of C. zofingiensis and underlying mechanisms of TAG and astaxanthin biosynthesis, provide engineering implications into future trait improvements, and will benefit the development of this alga for production uses under saline environment, thus reducing the footprint of freshwater.

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Section: Salt Stress Promotes Fatty Acid Synthesis While Attenuating supporting

confidence: 84%

Novel insights into salinity-induced lipogenesis and carotenogenesis in the oleaginous astaxanthin-producing alga Chromochloris zofingiensis: a multi-omics study

Mao

Zhang

Wang

et al. 2020

Biotechnol Biofuels

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“…18 Microalgal genes related to cell growth, such as, nitrogen metabolismrelated genes (E1.7.1.1), carbon metabolism-related genes (EC:5.3.16), chloroplast synthesis-related genes (E1.1.1.39, EC:1.1.1.37, EC:1.1.1.37, and EC:2.7.9.1), and mitochondria synthesis-related genes (EC2.6.1.2, E1.1.1.40, and EC2.6.1.1), showed higher expression in the presence of 15% CO 2 than in the presence of air ( Table 2). 18 Microalgal genes related to cell growth, such as, nitrogen metabolismrelated genes (E1.7.1.1), carbon metabolism-related genes (EC:5.3.16), chloroplast synthesis-related genes (E1.1.1.39, EC:1.1.1.37, EC:1.1.1.37, and EC:2.7.9.1), and mitochondria synthesis-related genes (EC2.6.1.2, E1.1.1.40, and EC2.6.1.1), showed higher expression in the presence of 15% CO 2 than in the presence of air ( Table 2).…”

Section: Analysis Of Improvements In Biomass and Lipid Productivity Bmentioning

confidence: 99%

Simultaneous enhancement of microalgae biomass growth and lipid accumulation under continuous aeration with 15% CO₂

Huang

Cheng

et al. 2015

RSC Adv.

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To overcome the opposing trends in biomass yield and lipid accumulation, Chlorella PY-ZU1 cultures were continuously aerated with 15% CO 2 to simultaneously enhance biomass yield (2.78 g L À1 ) and lipid content (47.04%). Microalgal cells consumed almost all the nitrate in the culture after 1 day to synthesize 24 mg L À1 of chlorophyll, which supported a peak growth rate of 0.675 g L À1 per day. Meanwhile, increased expression of key enzymes related to lipid synthesis (e.g., acetyl coenzyme A) enhanced lipid productivity to 192.10 mg L À1 per day. During the growth process, the carbon content of the dried biomass increased from 47.00% to 56.02% while the nitrogen content decreased from 6.36% to 1.99%. The unsaturated fatty acids decreased and saturated fatty acids increased, thus improving the anti-oxidation stability of microalgal biodiesel.

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“…Based on current information, it appears that phytoplankton community composition shifts and that their ecological and physiological performances might be driven by (i) the extent to which they are able to respond to salinity changes, (ii) the magnitude and the frequency of the salinity gradient experienced, (iii) the balance between growth rates and salinity tolerance limits of a given species and (iv) their capacity for evolutionary adaptation. Although there is a growing number of studies examining the capacity for acclimation and/or the selection response of phytoplankton mutants over long‐term (LT) experiments, with cultures being performed of multiple years (Collins and Bell, ; Flores‐Moya et al ., ; Lohbeck et al ., ; Helliwell et al ., ), there is a surprising paucity in the literature of LT salinity acclimation experiments (Liu et al ., ) or experiments addressing the genomic response to this important environmental factor (Cheng et al ., ).…”

Section: Introductionmentioning

confidence: 97%

Physiological adjustments and transcriptome reprogramming are involved in the acclimation to salinity gradients in diatoms

Bussard

Corre

Hubas

et al. 2016

Environmental Microbiology

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Salinity regimes in estuaries and coastal areas vary with river discharge patterns, seawater evaporation, the morphology of the coastal waterways and the dynamics of marine water mixing. Therefore, microalgae have to respond to salinity variations at time scales ranging from daily to annual cycles. Microalgae may also have to adapt to physical alterations that induce the loss of connectivity between habitats and the enclosure of bodies of water. Here, we integrated physiological assays and measurements of morphological plasticity with a functional genomics approach to examine the regulatory changes that occur during the acclimation to salinity in the estuarine diatom Thalassiosira weissflogii. We found that cells exposed to different salinity regimes for a short or long period presented adjustments in their carbon fractions, silicon pools, pigment concentrations and/or photosynthetic parameters. Salinity-induced alterations in frustule symmetry were observed only in the long-term (LT) cultures. Whole transcriptome analyses revealed a down-regulation of nuclear and plastid encoded genes during the LT response and identified only a few regulated genes that were in common between the ST and LT responses. We propose that in diatoms, one strategy for acclimating to salinity gradients and maintaining optimal cellular fitness could be a reduction in the cost of transcription.

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Transcriptome and Gene Expression Analysis of an Oleaginous Diatom Under Different Salinity Conditions

Cited by 58 publications

References 53 publications

Novel insights into salinity-induced lipogenesis and carotenogenesis in the oleaginous astaxanthin-producing alga Chromochloris zofingiensis: a multi-omics study

Novel insights into salinity-induced lipogenesis and carotenogenesis in the oleaginous astaxanthin-producing alga Chromochloris zofingiensis: a multi-omics study

Simultaneous enhancement of microalgae biomass growth and lipid accumulation under continuous aeration with 15% CO₂

Physiological adjustments and transcriptome reprogramming are involved in the acclimation to salinity gradients in diatoms

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Transcriptome and Gene Expression Analysis of an Oleaginous Diatom Under Different Salinity Conditions

Cited by 58 publications

References 53 publications

Novel insights into salinity-induced lipogenesis and carotenogenesis in the oleaginous astaxanthin-producing alga Chromochloris zofingiensis: a multi-omics study

Novel insights into salinity-induced lipogenesis and carotenogenesis in the oleaginous astaxanthin-producing alga Chromochloris zofingiensis: a multi-omics study

Simultaneous enhancement of microalgae biomass growth and lipid accumulation under continuous aeration with 15% CO2

Physiological adjustments and transcriptome reprogramming are involved in the acclimation to salinity gradients in diatoms

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Simultaneous enhancement of microalgae biomass growth and lipid accumulation under continuous aeration with 15% CO₂