Treinamento complexo e dinâmico de luz e sistema de memória na Arabidopsis

terça-feira, julho 20, 2010

Plant Cell Advance Online Publication
Published on July 16, 2010; 10.1105/tpc.109.069302

Received June 12, 2009; Revision received June 8, 2010. accepted June 28, 2010.

Evidence for Light Wavelength-Specific Photoelectrophysiological Signaling and Memory of Excess Light Episodes in Arabidopsis[W],[OA]

Magdalena Szechynska-Hebdaa,b,1Jerzy KrukcMagdalena GóreckaaBarbara Karpinskaa and Stanislaw Karpinskia,1,2

a Department of Genetics, Breeding, and Plant Biotechnology, Faculty of Horticulture and Landscape Architecture, Warsaw University of Life Sciences, 02-776 Warszawa, Polandb Institute of Plant Physiology Polish Academy of Sciences, 30-239 Krakow, Polandc Department of Plant Physiology and Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, PL-30-387 Krakow, Poland

2 Address correspondence to

Although light is essential for photosynthesis, excess light can damage the photosynthetic apparatus and deregulate other cellular processes. Thus, protective integrated regulatory responses that can dissipate excess of absorbed light energy and simultaneously optimize photosynthesis and other cellular processes under variable light conditions can prove highly adaptive. Here, we show that the local and systemic responses to an excess light episode are associated with photoelectrophysiological signaling (PEPS) as well as with changes in nonphotochemical quenching and reactive oxygen species levels. During an excess light incident, PEPS is induced by quantum redox changes in photosystem II and in its proximity and/or by changes in glutathione metabolism in chloroplasts. PEPS is transduced, at least in part, by bundle sheath cells and is light wavelength specific. PEPS systemicpropagation speed and action potential are dependent on ASCORBATE PEROXIDASE2 function. Excess light episodes are physiologicallymemorized in leaves, and the cellular light memory effect is specific for an excess of blue (450 nm) and red (650 nm) light of similar energy. It is concluded that plants possess a complex and dynamic light training and memory system that involves quantum redox, reactive oxygen species, hormonal, and PEPS signaling and is used to optimize light acclimation and immune defenses.



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