A non-photosynthetic green alga illuminates the reductive evolution of plastid electron transport systems
| العنوان: | A non-photosynthetic green alga illuminates the reductive evolution of plastid electron transport systems |
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| المؤلفون: | Tomonori Azuma, Takashi Nakada, Toshiharu Shikanai, Ryoma Kamikawa, Motoki Kayama, Shinichi Takaichi, Jun-Feng Chen, Yuichiro Kashiyama, Yoshiki Nishimura, Hideaki Miyashita |
| المصدر: | BMC Biology, Vol 18, Iss 1, Pp 1-15 (2020) BMC Biology |
| بيانات النشر: | Springer Science and Business Media LLC, 2020. |
| سنة النشر: | 2020 |
| مصطلحات موضوعية: | 0106 biological sciences, Physiology, Plastoquinone, Plant Science, Biology, Photosynthesis, Plastoquinol, 01 natural sciences, Plastid terminal oxidase, General Biochemistry, Genetics and Molecular Biology, Electron Transport, Evolution, Molecular, 03 medical and health sciences, chemistry.chemical_compound, Chlorophyceae, Structural Biology, NADPH, Plastids, Plastid, lcsh:QH301-705.5, Ecology, Evolution, Behavior and Systematics, Transient RNA interference knockdown, 030304 developmental biology, Carotenoid, Non-photosynthetic plastid, 0303 health sciences, fungi, food and beverages, Cell Biology, Apicoplasts, Electron transport chain, Metabolic pathway, lcsh:Biology (General), chemistry, Thylakoid, Biophysics, General Agricultural and Biological Sciences, Research Article, 010606 plant biology & botany, Developmental Biology, Biotechnology |
| الوصف: | Background Plastid electron transport systems are essential not only for photosynthesis but also for dissipating excess reducing power and sinking excess electrons generated by various redox reactions. Although numerous organisms with plastids have lost their photoautotrophic lifestyles, there is a spectrum of known functions of remnant plastids in non-photosynthetic algal/plant lineages; some of non-photosynthetic plastids still retain diverse metabolic pathways involving redox reactions while others, such as apicoplasts of apicomplexan parasites, possess highly reduced sets of functions. However, little is known about underlying mechanisms for redox homeostasis in functionally versatile non-photosynthetic plastids and thus about the reductive evolution of plastid electron transport systems. Results Here we demonstrated that the central component for plastid electron transport systems, plastoquinone/plastoquinol pool, is still retained in a novel strain of an obligate heterotrophic green alga lacking the photosynthesis-related thylakoid membrane complexes. Microscopic and genome analyses revealed that the Volvocales green alga, chlamydomonad sp. strain NrCl902, has non-photosynthetic plastids and a plastid DNA that carries no genes for the photosynthetic electron transport system. Transcriptome-based in silico prediction of the metabolic map followed by liquid chromatography analyses demonstrated carotenoid and plastoquinol synthesis, but no trace of chlorophyll pigments in the non-photosynthetic green alga. Transient RNA interference knockdown leads to suppression of plastoquinone/plastoquinol synthesis. The alga appears to possess genes for an electron sink system mediated by plastid terminal oxidase, plastoquinone/plastoquinol, and type II NADH dehydrogenase. Other non-photosynthetic algae/land plants also possess key genes for this system, suggesting a broad distribution of an electron sink system in non-photosynthetic plastids. Conclusion The plastoquinone/plastoquinol pool and thus the involved electron transport systems reported herein might be retained for redox homeostasis and might represent an intermediate step towards a more reduced set of the electron transport system in many non-photosynthetic plastids. Our findings illuminate a broadly distributed but previously hidden step of reductive evolution of plastid electron transport systems after the loss of photosynthesis. |
| تدمد: | 1741-7007 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::75d9ba7051f46273a126d5a5372c1ed0 https://doi.org/10.1186/s12915-020-00853-w |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi.dedup.....75d9ba7051f46273a126d5a5372c1ed0 |
| قاعدة البيانات: | OpenAIRE |
Find this article in full text from Springer Verlag. | تدمد: | 17417007 |
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