Amit Kumar Sharma

• Nymark, Marianne; Finazzi, Giovanni; Volpe, Charlotte; Serif, Manuel Philipp; Fonseca, Davi de Miranda & Sharma, Animesh [Show all 12 contributors for this article] (2023). Loss of CpFTSY Reduces Photosynthetic Performance and Affects Insertion of PsaC of PSI in Diatoms. Plant and Cell Physiology. ISSN 0032-0781. 64(6), p. 583–603. doi: 10.1093/pcp/pcad014. Full text in Research Archive
• Sharma, Amit Kumar; Nymark, Marianne; Flo, Snorre; Sparstad, Torfinn; Bones, Atle M. & Winge, Per (2021). Simultaneous knockout of multiple LHCF genes using single sgRNAs and engineering of a high-fidelity Cas9 for precise genome editing in marine algae. Plant Biotechnology Journal. ISSN 1467-7644. 19, p. 1–12. doi: 10.1111/pbi.13582. Full text in Research Archive
• Sharma, Amit Kumar; Mühlroth, Alice; Jouhet, Juliette; Maréchal, Eric; Alipanah, Leila & Kissen, Ralph [Show all 9 contributors for this article] (2019). The Myb like transcription factor Phosphorus Starvation Response (PtPSR) controls conditional P acquisition and remodeling in marine microalgae. New Phytologist. ISSN 0028-646X. 225(6), p. 2380–2395. doi: 10.1111/nph.16248. Full text in Research Archive Show summary

  Phosphorus (P) is one of the limiting macronutrients for algal growth in marine environments. Microalgae have developed adaption mechanisms to P limitation that involve remodelling of internal phosphate resources and accumulation of lipids. Here, we used in silico analyses to identify the P stress regulator PtPSR (Phaeodactylum tricornutum Phosphorus Starvation Response) in the diatom Phaeodactylum tricornutum. ptpsr mutant lines were generated using gene editing and characterised by various molecular, genetics and biochemical tools. PtPSR belongs to a clade of Myb transcription factors that are conserved in stramenopiles and distantly related to plant P stress regulators. PtPSR bound specifically to a conserved cis-regulatory element found in the regulatory region of P stress-induced genes. ptpsr knock-out mutants showed reduction in cell growth under P limitation. P stress responses were impaired in ptpsr mutants compared with wild-type, including reduced induction of P stress response genes, near to complete loss of alkaline phosphatase activity and reduced phospholipid degradation. We conclude that PtPSR is a key transcription factor influencing P scavenging, phospholipid remodelling and cell growth in adaption to P stress in diatoms.

• Sharma, Amit Kumar; Nymark, Marianne; Sparstad, Torfinn; Bones, Atle M. & Winge, Per (2018). Transgene-free genome editing in marine algae by bacterial conjugation - comparison with biolistic CRISPR/Cas9 transformation. Scientific Reports. ISSN 2045-2322. 8(1), p. 1–11. doi: 10.1038/s41598-018-32342-0. Full text in Research Archive
• Nymark, Marianne; Sharma, Amit Kumar; Hafskjold, Marthe; Sparstad, Torfinn; Bones, Atle M. & Winge, Per (2017). CRISPR/Cas9 Gene Editing in the Marine Diatom Phaeodactylum tricornutum. Bio-protocol. ISSN 2331-8325. 7(15). doi: 10.21769/BioProtoc.2442.
• Nymark, Marianne; Sharma, Amit Kumar; Sparstad, Torfinn; Bones, Atle M. & Winge, Per (2016). A CRISPR/Cas9 system adapted for gene editing in marine algae. Scientific Reports. ISSN 2045-2322. 6. doi: 10.1038/srep24951. Full text in Research Archive

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• Sharma, Amit Kumar; Nymark, Marianne; Bones, Atle M. & Winge, Per (2022). Simultaneous KO and mutation of five Light Harvesting Complex (LHC) genes, effect on photophysiology and study of the genomic rearrangements .
• Bones, Atle M.; Sharma, Amit Kumar; Winge, Per; Mühlroth, Alice; Brembu, Tore & Serif, Manuel [Show all 7 contributors for this article] (2021). Diatom genomics and gene regulation.
• Brembu, Tore; Sharma, Amit Kumar; Alipanah, Leila; Rohloff, Jens; Mühlroth, Alice & Bones, Atle M. [Show all 7 contributors for this article] (2021). Diatom responses to nitrogen and phosphorus limitation.
• Bones, Atle M.; Winge, Per; Sharma, Amit Kumar; Datsomor, Alex Kojo; Serif, Manuel Philipp & Nymark, Marianne (2020). A tool-box for analyses and functional studies of marine microalgae and salmonids.
• Bones, Atle M.; Winge, Per; Sharma, Amit Kumar & Nymark, Marianne (2019). Gene editing used to study the light harvesting complex of marine algae.
• Brembu, Tore; Sharma, Amit Kumar; Mühlroth, Alice; Jouhet, Juliette; Maréchal, Eric & Alipanah, Leila [Show all 8 contributors for this article] (2019). A transcription factor (PtPSR) controlling P acquisition in Phaeodactylum tricornutum.
• Nymark, Marianne; Sharma, Amit Kumar; Volpe, Charlotte; Flo, Snorre; Hafskjold, Marthe C.G. & Kirst, Henning [Show all 10 contributors for this article] (2019). A systems analysis of the light harvesting complex in diatoms.
• Nymark, Marianne; Volpe, Charlotte; Hafskjold, Marthe; Winge, Per; Sharma, Amit Kumar & Chauton, Matilde Skogen [Show all 8 contributors for this article] (2018). Genredigering av marine mikroalger - Kan endringer av algenes lyshøstingsegenskaper øke produktiviteten? .
• Bones, Atle M.; Winge, Per; Sharma, Amit Kumar; Volpe, Charlotte & Nymark, Marianne (2018). Genome editing of marine microalgae for characterization and metabolic engineering. Show summary

  Up to 2018 tens of thousands of transgenic organisms have been produced using gene transformation methods introducing random insertions of transgene material in the genomes of plant and animal cells. New technological developments based on guided insertions in given positions of the genome and simultaneously modification of homologous alleles have opened-up for functional studies and metabolic engineering. Methods like CRISPR/Cas9 and TALEN includes sequences guiding nucleases to the position where a mutation or some other type of modification is to be introduced. Marine microalgae are the major primary producers of the oceans. Over the last 10-20 year´s genome sequencing and development of the genetic tool-box and establishment of algal model species has opened for genetic manipulation of marine algae. One problem of using traditional genetic manipulation of diploid model marine microalgae is the absence in the lab systems of a method to produce homozygous modified cell lines. Breeding, forward genetic screens by random insertion, and chemical mutagenesis are therefore not applicable to the available diatom model species like Phaeodactylum tricornutum. Recently, methods for the use of tailored TALEN and CRISPR/Cas9 endonucleases have been developed for marine algae allowing targeted genetic modifications and the generation of knockout strains (1,2). Such stable mutant strains are extremely valuable for research. We have used CRISPR/Cas technology to knock-out genes involved in the assembly of the pigment-protein complex forming the light harvesting antennae where the aim is to produce cell lines having a higher light energy to biomass conversion rate. We also provide some new insight about genes regulating nutrient starvation responses in marine microalgae (3).

• Bones, Atle M.; Nymark, Marianne; Datsomor, Alex; Sharma, Amit Kumar & Winge, Per (2017). Enterering a new era in aquaculture through biotechnology.
• Nymark, Marianne; Hafskjold, Marthe C.G.; Sharma, Amit Kumar; Winge, Per & Bones, Atle M. (2017). Microalgae research in Norway.
• Nymark, Marianne; Hafskjold, Marthe C.G.; Sharma, Amit Kumar; Bones, Atle M. & Winge, Per (2017). Downsizing the light harvesting complex through gene editing of the chloroplast SRP pathway in P. tricornutum.
• Nymark, Marianne; Hafskjold, Marthe C.G.; Sharma, Amit Kumar; Bones, Atle M. & Winge, Per (2016). Downsizing the light harvesting complex through CRISPR/Cas9 gene editing of the chloroplast SRP pathway in marine diatoms.
• Nymark, Marianne; Winge, Per; Bones, Atle M. & Sharma, Amit Kumar (2016). Efficient knock out of a member of the chloroplast signal recognition particle pathway using the CRISPR-Cas system.

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