IMPROVEMENT OF STRESS TOLERANCE IN TOBACCO PLANTS BY EXPRESSING CYANOBACTERIAL FLAVODIIRON PROTEINS

GOMEZ RODRIGO; LODEYRO ANABELLA; HAJIREZAEI MOHAMMAD-REZA; CARRILLO NÉSTOR

Córdoba

Congreso; LII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2016

SAIB

Flavodiiron proteins (Flvs) constitute a large family of enzymes distributed among bacteria, archaea, protists and gymnosperms but absent from angiosperms. In the cyanobacterium Synechoystis sp. PCC 6803, Flvs are encoded by four different genes (flv1-4) and form two functional heterodimers. The first one, Flv1-Flv3, is a soluble NADPH-reductase which dissipates the excess of reducing power by consuming NADPH and transferring the hydrides to dioxygen to form water in a single step. The action of these enzymes helps to avoid oxidative stress under unfavorable growth conditions. Using Agrobacterium-mediated transformation we generated plants expressing the Flv1-Flv3 dimer in chloroplasts. These plants were used to evaluate stress tolerance and photosynthetic performance under different growth conditions. The results of chlorophyll fluorescence assays show an improvement in photosynthetic efficiency and faster dissipation of excessive energy in the transgenic lines compared with wild-type plants, even under stress conditions. Moreover, transgenic plants display bigger size than controls as it was determined by comparing total leaf area and fresh/dry weight. Taken together, these observations suggest an increase in stress tolerance, faster adaptation to environmental fluctuations and enhanced biomass production by expression of the cyanobacterial Flv1-Flv3 dimer in higher plants.