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ABSTRACT
Photosynthesis is the process through which plants convert light energy into chemical energy and support all life activities on earth. The intensity and quality of sunlight in the natural environment can vary throughout the day. Therefore, plants have evolved numerous biochemical and developmental mechanisms to light that help plants to optimize their photosynthetic output and growth. To survive under such dramatically change environments, plants have acquired sophisticated mechanisms to regulate the photosynthetic process. One of the mechanisms is non-photochemical quenching (NPQ). The regulatory and molecular adaptation protects the photosynthetic apparatus of plants and algae from photo-damage by dissipating excess light energy in the form of heat and by preventing the accumulation of highly damaging reactive oxygen species. It has been reported that the above process is regulated by some regulatory proteins such as FLAP1 (Fluctuating light acclimation protein 1) and DLDG1 (Day-Length dependent Delayed-Greening1). DLDG1 is 438 amino-acid residues long NPQ regulatory protein found in the chloroplast envelope of the Arabidopsis genome.Evidences showed that these regulatory proteins play an essential role in the extrusion of the proton into the medium upon illumination with light and hence, it might be involved in controlling chloroplast H+ homeostasis for acclimation to changes in light intensity.

Keywords: Non-photochemical quenching, DLDG1, de-epoxidation, FLAP1, violaxanthin de-epoxidase

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Non Photochemical quenching A protective mechanism against Photodamage in Plants (1)_compressed.pdf