Increased lipid production by heterologous expression of AtWRI1 transcription factor in Nannochloropsis salina
Abstract Background Genetic engineering of microalgae is necessary to produce economically feasible strains for biofuel production. Current efforts are focused on the manipulation of individual metabolic genes, but the outcomes are not sufficiently stable and/or efficient for large-scale production...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2017-10-01
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| Series: | Biotechnology for Biofuels |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s13068-017-0919-5 |
| _version_ | 1817975966533681152 |
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| author | Nam Kyu Kang Eun Kyung Kim Young Uk Kim Bongsoo Lee Won-Joong Jeong Byeong-ryool Jeong Yong Keun Chang |
| author_facet | Nam Kyu Kang Eun Kyung Kim Young Uk Kim Bongsoo Lee Won-Joong Jeong Byeong-ryool Jeong Yong Keun Chang |
| author_sort | Nam Kyu Kang |
| collection | DOAJ |
| description | Abstract Background Genetic engineering of microalgae is necessary to produce economically feasible strains for biofuel production. Current efforts are focused on the manipulation of individual metabolic genes, but the outcomes are not sufficiently stable and/or efficient for large-scale production of biofuels and other materials. Transcription factors (TFs) are emerging as good alternatives for engineering of microalgae, not only to increase production of biomaterials but to enhance stress tolerance. Here, we investigated an AP2 type TF Wrinkled1 in Arabidopsis (AtWRI1) known as a key regulator of lipid biosynthesis in plants, and applied it to industrial microalgae, Nannochloropsis salina. Results We expressed AtWRI1 TF heterologously in N. salina, named NsAtWRI1, in an effort to re-enact its key regulatory function of lipid accumulation. Stable integration AtWRI1 was confirmed by RESDA PCR, and its expression was confirmed by Western blotting using the FLAG tag. Characterizations of transformants revealed that the neutral and total lipid contents were greater in NsAtWRI1 transformants than in WT under both normal and stress conditions from day 8. Especially, total lipid contents were 36.5 and 44.7% higher in NsAtWRI1 2–3 than in WT under normal and osmotic stress condition, respectively. FAME contents of NsAtWRI1 2–3 were also increased compared to WT. As a result, FAME yield of NsAtWRI1 2–3 was increased to 768 mg/L/day, which was 64% higher than that of WT under the normal condition. We identified candidates of AtWRI1-regulated genes by searching for the presence of the AW-box in promoter regions, among which lipid metabolic genes were further analyzed by qRT-PCR. Overall, qRT-PCR results on day 1 indicated that AtWRI1 down-regulated TAGL and DAGK, and up-regulated PPDK, LPL, LPGAT1, and PDH, resulting in enhanced lipid production in NsAtWRI1 transformants from early growth phase. Conclusion AtWRI1 TF regulated several genes involved in lipid synthesis in N. salina, resulting in enhancement of neutral lipid and FAME production. These findings suggest that heterologous expression of AtWRI1 TF can be utilized for efficient biofuel production in industrial microalgae. |
| first_indexed | 2024-04-13T21:56:16Z |
| format | Article |
| id | doaj.art-42fd4b8a53d9483a8649da5a76cc97c0 |
| institution | Directory Open Access Journal |
| issn | 1754-6834 |
| language | English |
| last_indexed | 2024-04-13T21:56:16Z |
| publishDate | 2017-10-01 |
| publisher | BMC |
| record_format | Article |
| series | Biotechnology for Biofuels |
| spelling | doaj.art-42fd4b8a53d9483a8649da5a76cc97c02022-12-22T02:28:14ZengBMCBiotechnology for Biofuels1754-68342017-10-0110111410.1186/s13068-017-0919-5Increased lipid production by heterologous expression of AtWRI1 transcription factor in Nannochloropsis salinaNam Kyu Kang0Eun Kyung Kim1Young Uk Kim2Bongsoo Lee3Won-Joong Jeong4Byeong-ryool Jeong5Yong Keun Chang6Department of Chemical and Biomolecular Engineering, KAISTAdvanced Biomass R&D CenterPlant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB)Department of Chemical and Biomolecular Engineering, KAISTPlant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB)Department of Chemical and Biomolecular Engineering, KAISTDepartment of Chemical and Biomolecular Engineering, KAISTAbstract Background Genetic engineering of microalgae is necessary to produce economically feasible strains for biofuel production. Current efforts are focused on the manipulation of individual metabolic genes, but the outcomes are not sufficiently stable and/or efficient for large-scale production of biofuels and other materials. Transcription factors (TFs) are emerging as good alternatives for engineering of microalgae, not only to increase production of biomaterials but to enhance stress tolerance. Here, we investigated an AP2 type TF Wrinkled1 in Arabidopsis (AtWRI1) known as a key regulator of lipid biosynthesis in plants, and applied it to industrial microalgae, Nannochloropsis salina. Results We expressed AtWRI1 TF heterologously in N. salina, named NsAtWRI1, in an effort to re-enact its key regulatory function of lipid accumulation. Stable integration AtWRI1 was confirmed by RESDA PCR, and its expression was confirmed by Western blotting using the FLAG tag. Characterizations of transformants revealed that the neutral and total lipid contents were greater in NsAtWRI1 transformants than in WT under both normal and stress conditions from day 8. Especially, total lipid contents were 36.5 and 44.7% higher in NsAtWRI1 2–3 than in WT under normal and osmotic stress condition, respectively. FAME contents of NsAtWRI1 2–3 were also increased compared to WT. As a result, FAME yield of NsAtWRI1 2–3 was increased to 768 mg/L/day, which was 64% higher than that of WT under the normal condition. We identified candidates of AtWRI1-regulated genes by searching for the presence of the AW-box in promoter regions, among which lipid metabolic genes were further analyzed by qRT-PCR. Overall, qRT-PCR results on day 1 indicated that AtWRI1 down-regulated TAGL and DAGK, and up-regulated PPDK, LPL, LPGAT1, and PDH, resulting in enhanced lipid production in NsAtWRI1 transformants from early growth phase. Conclusion AtWRI1 TF regulated several genes involved in lipid synthesis in N. salina, resulting in enhancement of neutral lipid and FAME production. These findings suggest that heterologous expression of AtWRI1 TF can be utilized for efficient biofuel production in industrial microalgae.http://link.springer.com/article/10.1186/s13068-017-0919-5MicroalgaeNannochloropsis salinaTranscription factorWrinkled1BiofuelsTF engineering |
| spellingShingle | Nam Kyu Kang Eun Kyung Kim Young Uk Kim Bongsoo Lee Won-Joong Jeong Byeong-ryool Jeong Yong Keun Chang Increased lipid production by heterologous expression of AtWRI1 transcription factor in Nannochloropsis salina Biotechnology for Biofuels Microalgae Nannochloropsis salina Transcription factor Wrinkled1 Biofuels TF engineering |
| title | Increased lipid production by heterologous expression of AtWRI1 transcription factor in Nannochloropsis salina |
| title_full | Increased lipid production by heterologous expression of AtWRI1 transcription factor in Nannochloropsis salina |
| title_fullStr | Increased lipid production by heterologous expression of AtWRI1 transcription factor in Nannochloropsis salina |
| title_full_unstemmed | Increased lipid production by heterologous expression of AtWRI1 transcription factor in Nannochloropsis salina |
| title_short | Increased lipid production by heterologous expression of AtWRI1 transcription factor in Nannochloropsis salina |
| title_sort | increased lipid production by heterologous expression of atwri1 transcription factor in nannochloropsis salina |
| topic | Microalgae Nannochloropsis salina Transcription factor Wrinkled1 Biofuels TF engineering |
| url | http://link.springer.com/article/10.1186/s13068-017-0919-5 |
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