期刊
AOB PLANTS
卷 6, 期 -, 页码 -出版社
OXFORD UNIV PRESS
DOI: 10.1093/aobpla/plu062
关键词
Chlamydomonas; malformed selenoprotein; mitochondrial superoxide; proteasome; reactive oxygen species; selenium; ubiquitin
资金
- United States National Science Foundation [MCB-1244009]
- Div Of Molecular and Cellular Bioscience
- Direct For Biological Sciences [1244009] Funding Source: National Science Foundation
The ubiquitin-proteasome pathway (UPP) coordinates a myriad of physiological processes in higher plants, including abiotic stress responses, but it is less well characterized in algal species. In this study, the green alga Chlamydomonas reinhardtii was used to gain insights into the role of the UPP during moderate and severe selenite stress at three different time points. The data indicate that activity of the UPP in response to selenium (Se) stress was both time and dose dependent. Moderate selenite stress increased proteasome activity, protein ubiquitination and the proteasomal removal of malformed selenoproteins. However, severe Se stress caused by prolonged selenite treatment or high selenite concentration decreased proteasome activity, inhibited protein ubiquitination and prevented the proteasomal removal of selenoproteins. The UPP impairment during severe Se stress was associated with the observed accumulation of reactive oxygen species (ROS), including mitochondrial superoxide. Additionally, proteasomal inhibition decreased the concentration of chlorophyll in cultures challenged with Se. Therefore, although the UPP protects Chlamydomonas against Se stress, severe oxidative stress induced by selenite toxicity likely hinders the UPP's capacity to mediate a stress response. The possibility that stress tolerance in plants is dependent upon optimal UPP activity and maintenance is discussed.
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