Abstract
Objective
The heterotrophic marine microalga, Schizochytrium mangrovei PQ6, synthesizes large amounts of polyunsaturated fatty acids (PUFAs) with possible nutritional applications. We characterized the transcriptome of S. mangrovei PQ6, focusing on lipid metabolism pathways throughout growth.
Result
Cell growth, total lipid, and docosahexaenoic acid (DHA, 22:6n-3) contents of S. mangrovei PQ6 in 500 ml batch cultures rapidly increased on day 1 in cultivation and reached their maximum levels on day 5. Maximum lipid accumulation in 500 ml batch cultures occurred on day 5, with total lipid and DHA contents reaching 33.2 ± 1.25% of dry cell weight (DCW) and 136 mg/g DCW, respectively. 11,025 unigenes, 28,617 unigenes and 18,480 unigenes from the transcriptomes of samples collected on day 1, 3, and 5 in cultivation were identified, respectively. These unigenes of the three samples were further assembled into 30,782 unigenes with an average size of 673 bp and N50 of 950 bp, and a total of 9,980 unigenes were annotated in public protein databases. 93 unigenes involved in lipid metabolism in which expression patterns corresponded with total lipid and DHA accumulation patterns were identified.
Conclusion
The possible roles of PUFAs pathways, such as those mediated by fatty acid synthase, polyketide synthase, and desaturase/elongase, co-exist in S. mangrovei PQ6.
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Acknowledgments
This study was supported by the National Research and Development Program of Biotechnology KC.04/11-15, the Ministry of Science and Technology, Vietnam under Grant number KC.04.20/11-15. We are grateful for the use of the facilities of National Key Laboratory, Institute of Biotechnology, VAST.
Supporting information
Methods—A-Transmission electron microscopy; B-De novo assembly of the S. mangrovei PQ6 transcriptome; C-Functional annotation; D-Differential gene expression analysis.
Supplementary Table 1—Primers used for qPCR.
Supplementary Table 2—Over representation analysis of specific enriched significant GO-slim terms on three cluster based on FPKM expression score.
Supplementary Table 3—Enzymes involved in fatty acid biosynthesis and metabolism identified by annotation of S. mangrovei PQ6 transcriptomes at different cultivation periods.
Supplementary Figure 1—The normal length distribution for BLASTX-annotated final unigene set (a) and high number of small-size unigenes for unannotated final unigene set (b).
Supplementary Figure 2—Gene Ontology (GO), Clusters of Orthologous Group (COG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) categories of assembled unigenes of S. mangrovei PQ6.
Supplementary Figure 3—Heat map plot of 1007 DEGs using the hierarchical clustering method from different growth stages
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Minh Hien Hoang and Cuong Nguyen have contributed equally to this work.
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Hoang, M.H., Nguyen, C., Pham, H.Q. et al. Transcriptome sequencing and comparative analysis of Schizochytrium mangrovei PQ6 at different cultivation times. Biotechnol Lett 38, 1781–1789 (2016). https://doi.org/10.1007/s10529-016-2165-5
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DOI: https://doi.org/10.1007/s10529-016-2165-5