Project's information

Project's title Genome Sequencing and Analysis of Thraustochytrium sp. TN22
Project’s code VAST02.03/19-20
Research hosting institution Institute of Biotechnology
Project leader’s name Dr. Hoang Thi Minh Hien
Project duration 01/01/2019 - 31/12/2021
Project’s budget 600 million VND
Classify Excellent
Main results

- The assembled genome of heterotrophic mirine microalgae Thraustochytrium sp. TN22 was approximately 38.84 Mb long;
- DNA-seq raw data of of heterotrophic mirine microalgae Thraustochytrium sp. TN22 were deposited in the NCBI Sequence Read Archive (NCBI SRA) under accession number JABLUY000000000;
- The hybrid high-quality assembled genome of Thraustochytrium sp. TN22 was conducted with a total length of 38.84 Mb including 687 scaffolds and 24.643 contigs with 66.52% of the GC ratio,  N50 scaffold length of 120,033 bp and N50 contig length of 115.737 bp. Validation of the genome assembly using BUSCO analysis indicated fairly good completeness of our genome (90.4%);
- The genome of Thraustochytrium sp. TN22 contained 31,718 exon; 16,510 intron and 15,208 genes. Among the predicted genes, 14,236 (93.61%) predicted coding genes were detected, of which 11,340 genes, 3,773 genes, 9,371 genes, 13,405 genes and 14,236 genes had homologous hits by BLAST, KEGG, GO, COG and InterProScan searches, respectively;
- From the KEGG analysis, 37 genes, 12, 30, 14, 10 were identified and assigned to fatty acid metabolism (ko01212), fatty acid elongation (ko00062), fatty acid degradation (ko00071), fatty acid biosynthesis (ko00061) and biosynthesis of unsaturated fatty acids (ko01040), respectively.
- The database of genes involved in PUFAs biosynthesis pathway in Thraustochytrium sp. TN22 was indentified. The results indicate that both aerobic and anaerobic pathways exits for the biosynthesis of PUFAs in Thraustochytrium sp. TN22. However, the aerobic pathway might not be complete and not functional for the biosynthesis of DHA. Additionally, the biosynthesis pathway of carotenoid and squalene also was indicate.
- The key gene encoding enzyme involved in the PUFAs biosynthetic pathway as well as their expression levels in Thraustochytrium sp. TN22 growing in low and high lipid accumulation conditions were identified. They are polyunsaturated fatty acid synthase subunit A, polyunsaturated fatty acid synthase subunit B, polyunsaturated fatty acid synthase subunit C (EC:4.2.1.59), FAS (EC: 2.3.1.85 và EC: 2.3.1.86), 5-desaturase (EC: 2.3.1.199), 4-desaturase (EC 1.14.19.31), fatty acid desaturase 3 (EC:1.14.19), delta-9 fatty acid elongase (EC:2.3.1.199), elongation of very long chain fatty acids protein 5 (EC:2.3.1.199), elongation of very long chain fatty acids protein 6 (EC:2.3.1.199).

Novelty and actuality and scientific meaningfulness of the results

Up to now, in Vietnam, there has not been a study related to the genome, transcription and specific characteristics for fatty acid biosynthesis pathway/mechanism of species belong to the genus Thraustochytrium. Therefore, th obtained reults in this project is completely new and they will make important contributions to science in elucidating fatty acid synthesis pathways in each organism thereby opening up the possibility of fatty acid synthesis by genetic enginering by transferring genes into other desirable organisms such as oil plants to increase lipid and fatty acid synthesis.

Products of the project

Technological products
- Report on “Genome database of heterotrophic marine microalga Thraustochytrium sp. TN22”
- Report on “Scientific data for the biosynthetic pathway, especially fatty acid metabolism and molecular markers involved in this pathway in the heterotrophic marine microalgae Thraustochytrium sp. TN22”
- Report on "Assessing of the applicability of heterotrophic marine microalgae Thraustochytrium sp. TN22 is based on its genomic information”
Scientific papers in referred journals (list):
- Hien HTM, Thom LT, Pham QH, Hong DD. 2022. Genome analysis of the heterotrophic microalga Thraustochytrium sp. TN22 to identify genes involved in exopolysaccharide and carotenoid biosynthesis pathways. Marine Genomics 61: 100918. doi.org/10.1016/j.margen.2021.100918.
- Hien HTM, Thom LT, Ha NC, Anh HTL, Hong DD. 2020. Optimization of culture condition for squalene production and squalene extraction method of Thraustochytrium sp. TN22. Academia Journal of Biology 42(4): 73-85
- Hoang Thi Minh Hien, Pham Quang Huy, Le Thi Thom, Nguyen Cam Ha, Ngo Thi Hoai Thu, Luu Thi Tam, Dang Diem Hong. Genomic analysis of heterotrophic marine microalgae Thraustochytrium sp. TN22 to identify genes involed in secondary metabolic pathways. Abstract proceedings at “Rencontres de Quy Nhon III” Biology confrence 2020, ICISE Quy Nhon, December 11-13, 2020.

Research area

Thraustochytrium sp. TN22 genome sequence generated in this project represents a new source of knowledge which can be used as a reference to study Thraustochytrids and it will help to further understand the genetic mechanisms for biosynthesis and regulation of polyunsaturated fatty acids and other value-added compounds as squalene, carotenoid ... It will also be valuable in comparative genomic studies of other Thraustochytrium sp. strains as well as for metabolic engineering of Thraustochytrids. The data of this project are also useful for researchers who work in the fields of microbial biotechnology, food technology, genetic engineering and renewable energy.

Recommendations

This is the first report of genome sequencing and analysis of Thraustochytrium sp. TN22 to dentify gene involved in PUFAs, carotenoid, squalene biosynthesis pathway. The biosynthesis mechanism of PUFAs, squalene and carotenoid in Thraustochytrium sp. TN22 has just been predicted based on genome anotation, therefore it is nessecery to confirm this hypothesis based on a research on transcriptome of this strain at different culture condition for accumulation of products at low and high levels.           

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