Research
| Title： | UV-B RADIATION INHIBITS THE PHOTOSYNTHETIC ELECTRON TRANSPORT CHAIN IN CHLAMYDOMONAS REINHARDTII |
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| First author： | Cai, Wenkai; Gao, Xiang; Hu, Jinlu; Chen, Lanzhou; Li, Xiaoyan; Liu, Yongding; Wang, Gaohong |
| Journal： | PAKISTAN JOURNAL OF BOTANY |
| Years： | 2016 |
| DOI： | |
| Abstract： | UV radiation of sunlight is one of harmful factors for earth organisms, especially for photoautotrophs because they require light for energy and biomass production. A number of works have already been done regarding the effects of UV-B radiation at biochemical and molecular level, which showed that UV-B radiation could inhibit photosynthesis activity and reduce photosynthetic electron transport. However quite limited information can accurately make out inhibition site of UV-B radiation on photosynthetic electron transport. In this study, this issue was investigated through measuring oxygen evolution activity, chlorophyll a fluorescence and gene expression in a model unicellular green alga Chlamydomonas reinhardtii. Our results indicated that UV-B radiation could evidently decrease photosynthesis activity and inhibit electron transport by blocking electron transfer process from the first plastoquinone electron acceptors Q(A) to second plastoquinone electron acceptors Q(B), but not impair electron transfer from the water oxidizing complex to Q(A). The psbA gene expression was also altered by UV-B radiation, where up-regulation occurred at 2, 4 and 6h after exposure and down-regulation happened at 12 and 24 h after exposure. These results suggested that UV-B could affects D1 protein normal turnover, so there was not enough D1 for binding with Q(B), which may affect photosynthetic electron transport and photosynthesis activity. |
