Tim Michelberger, Eleonora Mezzadrelli, Alessandra Bellan, Giorgio Perin, Tomas Morosinotto
{"title":"海洋纳米绿藻的叶黄素循环平衡光保护和光合效率。","authors":"Tim Michelberger, Eleonora Mezzadrelli, Alessandra Bellan, Giorgio Perin, Tomas Morosinotto","doi":"10.1093/plphys/kiaf301","DOIUrl":null,"url":null,"abstract":"<p><p>Photosynthetic reactions are continuously modulated to respond to highly dynamic environmental conditions. Balancing photosynthesis and photoprotection involves various mechanisms, which differ across phylogenetic groups. One such mechanism that is widespread in photosynthetic eukaryotes is the xanthophyll cycle, which involves the reversible light-dependent conversion between the carotenoids violaxanthin, antheraxanthin, and zeaxanthin. In this study, we investigated the role of the xanthophyll cycle in Nannochloropsis oceanica, a seawater microalga that possesses peculiarly high xanthophyll levels. To this end, we generated and characterized lines with increased levels of the enzymes involved in the xanthophyll cycle, i.e., violaxanthin de-epoxidase (VDE) and zeaxanthin epoxidase (ZEP). We demonstrated that the level of VDE and ZEP is the main factor controlling the overall reaction rates and dynamics of the xanthophyll cycle. Subsequent differences in the xanthophyll profile affect the activation of photoprotection mechanisms such as non-photochemical quenching and tolerance to reactive oxygen species. Interestingly, VDE overexpression enhances high light tolerance, whereas increased ZEP levels facilitate faster recovery after light exposure but also heighten photosensitivity under certain conditions. In addition, light exposure strongly downregulates ZEP activity in Nannochloropsis. Taken together, these findings underscore the critical role of the xanthophyll cycle in regulating photosynthesis in Nannochloropsis. This cycle is not simply a mechanism that responds to excess illumination, but one that balances photoprotection and light-use efficiency under different environmental conditions.</p>","PeriodicalId":20101,"journal":{"name":"Plant Physiology","volume":" ","pages":""},"PeriodicalIF":6.5000,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The Xanthophyll Cycle balances Photoprotection and Photosynthetic Efficiency in the seawater alga Nannochloropsis oceanica.\",\"authors\":\"Tim Michelberger, Eleonora Mezzadrelli, Alessandra Bellan, Giorgio Perin, Tomas Morosinotto\",\"doi\":\"10.1093/plphys/kiaf301\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Photosynthetic reactions are continuously modulated to respond to highly dynamic environmental conditions. Balancing photosynthesis and photoprotection involves various mechanisms, which differ across phylogenetic groups. One such mechanism that is widespread in photosynthetic eukaryotes is the xanthophyll cycle, which involves the reversible light-dependent conversion between the carotenoids violaxanthin, antheraxanthin, and zeaxanthin. In this study, we investigated the role of the xanthophyll cycle in Nannochloropsis oceanica, a seawater microalga that possesses peculiarly high xanthophyll levels. To this end, we generated and characterized lines with increased levels of the enzymes involved in the xanthophyll cycle, i.e., violaxanthin de-epoxidase (VDE) and zeaxanthin epoxidase (ZEP). We demonstrated that the level of VDE and ZEP is the main factor controlling the overall reaction rates and dynamics of the xanthophyll cycle. Subsequent differences in the xanthophyll profile affect the activation of photoprotection mechanisms such as non-photochemical quenching and tolerance to reactive oxygen species. Interestingly, VDE overexpression enhances high light tolerance, whereas increased ZEP levels facilitate faster recovery after light exposure but also heighten photosensitivity under certain conditions. In addition, light exposure strongly downregulates ZEP activity in Nannochloropsis. Taken together, these findings underscore the critical role of the xanthophyll cycle in regulating photosynthesis in Nannochloropsis. This cycle is not simply a mechanism that responds to excess illumination, but one that balances photoprotection and light-use efficiency under different environmental conditions.</p>\",\"PeriodicalId\":20101,\"journal\":{\"name\":\"Plant Physiology\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":6.5000,\"publicationDate\":\"2025-07-04\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Plant Physiology\",\"FirstCategoryId\":\"99\",\"ListUrlMain\":\"https://doi.org/10.1093/plphys/kiaf301\",\"RegionNum\":1,\"RegionCategory\":\"生物学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"PLANT SCIENCES\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Plant Physiology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1093/plphys/kiaf301","RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PLANT SCIENCES","Score":null,"Total":0}
The Xanthophyll Cycle balances Photoprotection and Photosynthetic Efficiency in the seawater alga Nannochloropsis oceanica.
Photosynthetic reactions are continuously modulated to respond to highly dynamic environmental conditions. Balancing photosynthesis and photoprotection involves various mechanisms, which differ across phylogenetic groups. One such mechanism that is widespread in photosynthetic eukaryotes is the xanthophyll cycle, which involves the reversible light-dependent conversion between the carotenoids violaxanthin, antheraxanthin, and zeaxanthin. In this study, we investigated the role of the xanthophyll cycle in Nannochloropsis oceanica, a seawater microalga that possesses peculiarly high xanthophyll levels. To this end, we generated and characterized lines with increased levels of the enzymes involved in the xanthophyll cycle, i.e., violaxanthin de-epoxidase (VDE) and zeaxanthin epoxidase (ZEP). We demonstrated that the level of VDE and ZEP is the main factor controlling the overall reaction rates and dynamics of the xanthophyll cycle. Subsequent differences in the xanthophyll profile affect the activation of photoprotection mechanisms such as non-photochemical quenching and tolerance to reactive oxygen species. Interestingly, VDE overexpression enhances high light tolerance, whereas increased ZEP levels facilitate faster recovery after light exposure but also heighten photosensitivity under certain conditions. In addition, light exposure strongly downregulates ZEP activity in Nannochloropsis. Taken together, these findings underscore the critical role of the xanthophyll cycle in regulating photosynthesis in Nannochloropsis. This cycle is not simply a mechanism that responds to excess illumination, but one that balances photoprotection and light-use efficiency under different environmental conditions.
期刊介绍:
Plant Physiology® is a distinguished and highly respected journal with a rich history dating back to its establishment in 1926. It stands as a leading international publication in the field of plant biology, covering a comprehensive range of topics from the molecular and structural aspects of plant life to systems biology and ecophysiology. Recognized as the most highly cited journal in plant sciences, Plant Physiology® is a testament to its commitment to excellence and the dissemination of groundbreaking research.
As the official publication of the American Society of Plant Biologists, Plant Physiology® upholds rigorous peer-review standards, ensuring that the scientific community receives the highest quality research. The journal releases 12 issues annually, providing a steady stream of new findings and insights to its readership.