期刊
PLANT PHYSIOLOGY
卷 154, 期 1, 页码 346-356出版社
AMER SOC PLANT BIOLOGISTS
DOI: 10.1104/pp.110.159285
关键词
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资金
- Reiger Fellowship for Environmental Studies
- Deutscher Akademischer Austausch Dienst
- Israeli Ministry of Science
- European Research Council under the European Community [205150]
- Czech Science Foundation-Grantova agentura Ceske republiky [206/08/1683, AV0Z50200510]
- Bundesministerium fur Bildung und Forschung-Ministry of Science, Culture and Sport [GR1950]
The marine diazotrophic cyanobacterium Trichodesmium responds to elevated atmospheric CO2 partial pressure (pCO(2)) with higher N-2 fixation and growth rates. To unveil the underlying mechanisms, we examined the combined influence of pCO(2) (150 and 900 mu atm) and light (50 and 200 mu mol photons m(-2) s(-1)) on Trichodesmium IMS101. We expand on a complementary study that demonstrated that while elevated pCO(2) enhanced N-2 fixation and growth, oxygen evolution and carbon fixation increased mainly as a response to high light. Here, we investigated changes in the photosynthetic fluorescence parameters of photosystem II, in ratios of the photosynthetic units (photosystem I: photosystem II), and in the pool sizes of key proteins involved in the fixation of carbon and nitrogen as well as their subsequent assimilation. We show that the combined elevation in pCO(2) and light controlled the operation of the CO2-concentrating mechanism and enhanced protein activity without increasing their pool size. Moreover, elevated pCO(2) and high light decreased the amounts of several key proteins (NifH, PsbA, and PsaC), while amounts of AtpB and RbcL did not significantly change. Reduced investment in protein biosynthesis, without notably changing photosynthetic fluxes, could free up energy that can be reallocated to increase N-2 fixation and growth at elevated pCO(2) and light. We suggest that changes in the redox state of the photosynthetic electron transport chain and posttranslational regulation of key proteins mediate the high flexibility in resources and energy allocation in Trichodesmium. This strategy should enable Trichodesmium to flourish in future surface oceans characterized by elevated pCO(2), higher temperatures, and high light.
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