GPC Members Login
If you have any problems or have forgotten your login please contact [email protected]

Model by which plants adapt their photosynthetic metabolism to light intensity

Researchers from cicCartuja, a centre jointly run by the University of Seville and the Centro Superior de Investigaciones Científicas (Higher Scientific Research Centre -- CSIC), have proposed a model that explains the molecular mechanism used by plants to adapt their photosynthetic mechanism to light intensity.

Photosynthesis is Earth's primary production process for organic material and oxygen. During the day, CO2 fixation and photosynthetic metabolism remain active in plant chloroplasts via a regulatory mechanism in which redox systems like thioredoxins (TRXs) play a central role. The chloroplastic TRXs use ferredoxin (Fd) reduced by the photosynthetic flow of electrons, so connecting the metabolic regulation with the light. In addition, the chloroplasts have NTRC, an additional redox system, exclusive to photosynthetic organisms, which, as occurs in heterotrophic organisms, uses NADPH as reducing power.

Photosynthesis inevitably generates oxidising agents, such as hydrogen peroxide, which can be harmful. For this reason, the chloroplasts have protective systems like 2-cys peroxiredoxins (2CP), whose activity depends on NTRC, and so an antioxidant function has been proposed for this enzyme. However later studies have shown the participation of NTRC in metabolic processes regulated by TRXs, like starch and chlorophyll synthesis. These results suggest a profound interrelationship between redox systems based in Fd (TRXs) and NADPH (NTRC) and antioxidants by means of a mechanism with an unknown molecular base.

The authors of this study -- all researched from the institute of Plant Biochemistry and Photosynthesis, a joint University of Seville-CSIS centre, which is part of the Isla de la Cartuja Scientific Research Centre (cicCartuja) -- have shown that the functioning of photosynthetic metabolism and its adaptation to unpredictable changes in light intensity depend on the redox balance of the peroxiredoxins (2CP), which act by integrating the complex redox regulation systems of the chloroplasts.

These results -- obtained from the model species Arabidopsis thaliana -- signify an important advance in the knowledge of photosynthesis and suggest new biotechnological approaches for increasing both the photosynthetic rate of CO2 fixation and the consequent production of organic material.

Read the paper: NTRC-dependent redox balance of 2-Cys peroxiredoxins is needed for optimal function of the photosynthetic apparatus.

Article source: University of Seville.


Study examines medicinal compound in plant roots

Xanthones are specialized metabolites with antimicrobial properties that are found in the roots of medicinal plants called Hypericum perforatum, also known as St. John's wort. A New Phytologist study sheds light on the sites of synthesis and accumulation of xanthones in roots.

Does eclipse equal night in plant life?

On August 21, 2017, about 215 million American adults watched one of nature's most dramatic events: a total solar eclipse. However, most of the country could only see a partial eclipse. The path of the total eclipse was a strip just 70 miles wide, arcing across the country from Oregon to South Carolina.

Forest resilience declines in face of wildfires, climate change

The forests you see today are not what you will see in the future. That's the overarching finding from a new study on the resilience of Rocky Mountain forests, led by Colorado State University.