S-PM2 Bacteriophage as a Remedy for Photoinhibition in Agricultural Crops

Over exposure of plants to light causes Photoinhibition which leads to a halt in the photosynthetic pathway. The natural tendency of photoprotection in a plant gets exhausted due to severe photodamage. Photodamage is manifested as a decline in both quantum yield and Pmax, and recovers very slowly (hours to days). Some plants can survive through photoinhibition unharmed though with very low production of flowers and fruits. Severe photodamage results in bleaching of pigments, damage to membranes (photo-oxidation) and may even lead to tissue death. This occurs even in the agricultural food and cash crops. Some plant species are unable to recover from Photoinhibition, which greatly affects the quality of produce. This leads to a huge loss in the gross agricultural crop production output around the world. Light induced Photoinhibition is responsible for the reduction in efficiency of Photosystem II pathway. Because of this, the two important proteins D1 and D2 undergo severe damage (Richter et al., 1990a). Mann et al in the Volume 424 of Nature journal show that a bacteriophage known as S-PM2 encodes the D1 and D2 proteins, allowing Photosynthesis to continue in Cyanobacteria present in Oceans. If this bacteriophage is used to study the possibility of adopting such S-PM2 viruses in plants as well, a large amount of crop loss can be stopped. This paper will analyse the possibilities of using bacteriophages like S-PM2 to help plants recover from Photoinhibition by rebuilding D1 and D2 proteins. Photoinhibition can be reversible, playing a protective role for the photosynthetic systems, but it can also reflect damage that has already occurred in the photosynthetic apparatus, being irreversible in this case.