Genetic compensation of triacylglycerol biosynthesis in the green microalga Chlamydomonas reinhardtii

dc.contributor.authorLee, Yi-Ying
dc.contributor.authorPark, Rudolph
dc.contributor.authorMiller, Stephen M.
dc.contributor.authorLi, Yantao
dc.date.accessioned2022-08-12T18:05:04Z
dc.date.available2022-08-12T18:05:04Z
dc.date.issued2022-06-21
dc.description.abstractGenetic compensation has been proposed to explain phenotypic differences between gene knockouts and knockdowns in several metazoan and plant model systems. With the rapid development of reverse genetic tools such as CRISPR/Cas9 and RNAi in microalgae, it is increasingly important to assess whether genetic compensation affects the phenotype of engineered algal mutants. While exploring triacylglycerol (TAG) biosynthesis pathways in the model alga Chlamydomonas reinhardtii, it was discovered that knockout of certain genes catalyzing rate-limiting steps of TAG biosynthesis, type-2 diacylglycerol acyltransferase genes (DGTTs), triggered genetic compensation under abiotic stress conditions. Genetic compensation of a DGTT1 null mutation by a related PDAT gene was observed regardless of the strain background or mutagenesis approach, for example, CRISPR/Cas 9 or insertional mutagenesis. However, no compensation was found in the PDAT knockout mutant. The effect of PDAT knockout was evaluated in a Δvtc1 mutant, in which PDAT was upregulated under stress, resulting in a 90% increase in TAG content. Knockout of PDAT in the Δvtc1 background induced a 12.8-fold upregulation of DGTT1 and a 272.3% increase in TAG content in Δvtc1/pdat1 cells, while remaining viable. These data suggest that genetic compensation contributes to the genetic robustness of microalgal TAG biosynthetic pathways, maintaining lipid and redox homeostasis in the knockout mutants under abiotic stress. This work demonstrates examples of genetic compensation in microalgae, implies the physiological relevance of genetic compensation in TAG biosynthesis under stress, and provides guidance for future genetic engineering and mutant characterization efforts.en_US
dc.description.sponsorshipThis work was supported in part by grants from the US National Science Foundation (CBET-1511939) and DOE Office of Fossil Energy (FE-0031914) to YL, and by NSF 1332344 to SMM. The authors thank Drs William Snell, Peeyush Ranjan and Mayanka Awasthi at University of Maryland College park for their help with generating double knockout mutants, Dr Arthur Grossman at Carnegie Institution for Science for providing the Chlamydomonasvtc1strains used in this study, Dr Xiaobo Li at Westlake University for discussion of unpublished mutant screening data, and Drs Fan Zhang and Russell Hill at the Institute of Marine and Environmental Technology for their help with polyP analysis. The authors thank Mr Mohamed Mahmoud-Aly at Cairo University for his help with Chlamydomonas mutant characterization.en_US
dc.description.urihttps://onlinelibrary.wiley.com/doi/full/10.1111/tpj.15874en_US
dc.format.extent12 pagesen_US
dc.genrejournal articlesen_US
dc.identifierdoi:10.13016/m274cj-qrni
dc.identifier.citationLee, Y.-Y., Park, R., Miller, S.M. and Li, Y. (2022), Genetic compensation of triacylglycerol biosynthesis in the green microalga Chlamydomonas reinhardtii. Plant J. https://doi.org/10.1111/tpj.15874en_US
dc.identifier.urihttps://doi.org/10.1111/tpj.15874
dc.identifier.urihttp://hdl.handle.net/11603/25388
dc.language.isoen_USen_US
dc.publisherWileyen_US
dc.relation.isAvailableAtThe University of Maryland, Baltimore County (UMBC)
dc.relation.ispartofUMBC Biological Sciences Department Collection
dc.relation.ispartofUMBC Faculty Collection
dc.relation.ispartofUMBC Student Collection
dc.relation.ispartofUMBC Department of Marine Biotechnology
dc.rightsThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.en_US
dc.rightsAttribution-NonCommercial 4.0 International (CC BY-NC 4.0)*
dc.rights.urihttps://creativecommons.org/licenses/by-nc/4.0/*
dc.titleGenetic compensation of triacylglycerol biosynthesis in the green microalga Chlamydomonas reinhardtiien_US
dc.typeTexten_US
dcterms.creatorhttps://orcid.org/0000-0001-7545-1883en_US

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