{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T15:16:15Z","timestamp":1786115775591,"version":"build-2736575974"},"reference-count":48,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T00:00:00Z","timestamp":1785974400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Plant Sci."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>\n                      The diatom\n                      <jats:italic>Phaeodactylum tricornutum<\/jats:italic>\n                      is a premier biological platform for producing high-value polyunsaturated fatty acids (PUFAs). However, the transcriptional mechanisms coordinating lipid accumulation and fatty acid composition remain poorly understood.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      In this study, we characterized the role of the HMG-box transcriptional regulator\n                      <jats:italic>PtHMG1<\/jats:italic>\n                      in\n                      <jats:italic>P. tricornutum<\/jats:italic>\n                      through overexpression (OE) and CRISPR\/Cas9-mediated knockout (KO).\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Our results identify\n                      <jats:italic>PtHMG1<\/jats:italic>\n                      as a global regulator of lipid metabolism. PtHMG1-OE strains exhibited a 90% increase in total fatty acids and a rise in total lipids from 0.3\u00a0g g\n                      <jats:sup>-1<\/jats:sup>\n                      to 0.5\u00a0g g\n                      <jats:sup>-1<\/jats:sup>\n                      without significant growth inhibition. Although OE upregulated key front-end desaturases (PTD5a, PTD5b, and PTD6) and increased absolute eicosapentaenoic acid (EPA) content by 18%, the relative proportion of PUFAs declined due to the disproportionate accumulation of saturated and monounsaturated fatty acids. Conversely, PtHMG1-KO led to an 11% decrease in total lipids and significant growth defects. While KO strains showed downregulation of EPA-specific desaturases, a compensatory upregulation of alternative desaturases maintained a stable relative fatty acid profile.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>\n                      These findings demonstrate that\n                      <jats:italic>PtHMG1<\/jats:italic>\n                      plays a crucial role in regulating total lipid accumulation and modifying fatty acid composition in\n                      <jats:italic>P. tricornutum<\/jats:italic>\n                      . The decoupling of lipid enhancement from growth inhibition underscores the significant potential of utilizing\n                      <jats:italic>PtHMG1<\/jats:italic>\n                      for targeted genetic modification, facilitating the sustainable development of high-yield microalgal oils.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fpls.2026.1863846","type":"journal-article","created":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T05:32:34Z","timestamp":1785994354000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["The HMG-box protein PtHMG1 modulates lipid accumulation and fatty acid composition in the diatom Phaeodactylum tricornutum"],"prefix":"10.3389","volume":"17","author":[{"given":"Yuanfeng","family":"Li","sequence":"first","affiliation":[{"name":"School of Life Science, Ludong University","place":["Yantai, China"]},{"name":"Yantai Microalgae Engineering Technology Research Center","place":["Yantai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ning","family":"Ma","sequence":"additional","affiliation":[{"name":"School of Life Science, Ludong University","place":["Yantai, China"]},{"name":"Yantai Microalgae Engineering Technology Research Center","place":["Yantai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pu","family":"Song","sequence":"additional","affiliation":[{"name":"School of Life Science, Ludong University","place":["Yantai, China"]},{"name":"Yantai Microalgae Engineering Technology Research Center","place":["Yantai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shaokun","family":"Dong","sequence":"additional","affiliation":[{"name":"School of Life Science, Ludong University","place":["Yantai, China"]},{"name":"Yantai Microalgae Engineering Technology Research Center","place":["Yantai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ronglu","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Life Science, Ludong University","place":["Yantai, China"]},{"name":"Yantai Microalgae Engineering Technology Research Center","place":["Yantai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Youyi","family":"Zhou","sequence":"additional","affiliation":[{"name":"School of Life Science, Ludong University","place":["Yantai, China"]},{"name":"Yantai Microalgae Engineering Technology Research Center","place":["Yantai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongjin","family":"Qiao","sequence":"additional","affiliation":[{"name":"School of Life Science, Ludong University","place":["Yantai, China"]},{"name":"Yantai Microalgae Engineering Technology Research Center","place":["Yantai, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,8,6]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"875","DOI":"10.1104\/pp.112.198283","article-title":"Plant proteins containing high mobility group box DNA-binding domains modulate different nuclear processes","volume":"159","author":"Antosch","year":"2012","journal-title":"Plant Physiol."},{"key":"B2","doi-asserted-by":"publisher","first-page":"629","DOI":"10.1016\/s0031-9422(00)89787-3","article-title":"Biosynthesis of polyunsaturated lipids in the diatom, Phaeodactylum tricornutum","volume":"36","author":"Arao","year":"1994","journal-title":"Phytochemistry"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1016\/j.algal.2021.102450","article-title":"A bZIP transcription factor is involved in regulating lipid and pigment metabolisms in the green alga Chlamydomonas reinhardtii","volume":"59","author":"Bai","year":"2021","journal-title":"Algal Res."},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.3390\/nu12020356","article-title":"Biological role of unsaturated fatty acid desaturases in health and disease","volume":"12","author":"Czumaj","year":"2020","journal-title":"Nutrients"},{"key":"B5","doi-asserted-by":"publisher","first-page":"17","DOI":"10.1127\/pip\/2017\/0071","article-title":"Advances in editing microalgae genomes","volume":"4","author":"Daboussi","year":"2017","journal-title":"Perspect. 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