Arctic Micromonas uses protein pools and non-photochemical quenching to cope with temperature restrictions on Photosystem II protein turnover

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• 作者：Guangyan Ni ; Gabrielle Zimbalatti ; Cole D. Murphy…
• 关键词：Prasinophyte ; Photosystem II ; Photoinactivation ; Xanthophyll cycle
• 刊名：Photosynthesis Research
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：131
• 期：2
• 页码：203-220
• 全文大小：1534KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Plant Sciences; Plant Physiology; Biochemistry, general; Plant Genetics & Genomics;
• 出版者：Springer Netherlands
• ISSN：1573-5079
• 卷排序：131

文摘

Micromonas strains of small prasinophyte green algae are found throughout the world’s oceans, exploiting widely different niches. We grew arctic and temperate strains of Micromonas and compared their susceptibilities to photoinactivation of Photosystem II, their counteracting Photosystem II repair capacities, their Photosystem II content, and their induction and relaxation of non-photochemical quenching. In the arctic strain Micromonas NCMA 2099, the cellular content of active Photosystem II represents only about 50 % of total Photosystem II protein, as a slow rate constant for clearance of PsbA protein limits instantaneous repair. In contrast, the temperate strain NCMA 1646 shows a faster clearance of PsbA protein which allows it to maintain active Photosystem II content equivalent to total Photosystem II protein. Under growth at 2 °C, the arctic Micromonas maintains a constitutive induction of xanthophyll deepoxidation, shown by second-derivative whole-cell spectra, which supports strong induction of non-photochemical quenching under low to moderate light, even if xanthophyll cycling is blocked. This non-photochemical quenching, however, relaxes during subsequent darkness with kinetics nearly comparable to the temperate Micromonas NCMA 1646, thereby limiting the opportunity cost of sustained downregulation of PSII function after a decrease in light.