Improvement of stress tolerance in tobacco and Arabidopsis plants by expressing cyanobacterial flavodiiron proteins

VICINO PAULA; LODEYRO, ANABELLA F.; CARRILLO, NÉSTOR; CARRILLO, JULIETA

Congreso; Congreso SAIB-SAMIGE 2020; 2020

With the notable exception of angiosperms, all phototrophs contain different sets of flavodiiron (Flv) proteins which help to relieve the excess of excitation energy on the photosynthetic electron transport chain (PETC) during adverse environmental conditions, presumably by reducing oxygen directly to water. Among them, the Flv2-Flv4 dimer is only found in β-cyanobacteria and induced by high light, supporting a role in stress protection. However, the mechanism by which this set of proteins alleviate the electronic pressure on the PETC remains unknown. We therefore assayed for the first time the possibility of a similar protective function in plants by expressing Synechocystis Flv2-Flv4 in chloroplasts of tobacco plants. Flv-expressing plants exhibited increased tolerance toward high irradiation, salinity, oxidants and drought. Stress tolerance was reflected by better growth, preservation of photosynthetic activity, less reactive oxygen species production and membrane integrity. Particularly after drought stress, plants carrying Flv2-Flv4 proteins showed increased biomass accumulation. Our results indicate that the Flv2-Flv4 complex retains its stress protection activities when expressed in chloroplasts of angiosperm species by presumably acting as an additional electron sink. Then, flv2-flv4 genes constitute a novel biotechnological tool to generate plants with increased tolerance to agronomically relevant stress conditions that represent a significant productivity constraint.