IMPROVEMENT OF STRESS TOLERANCE IN TOBACCO PLANTS BY EXPRESSING CYANOBACTERIAL FLV2-FLV4 PROTEINS

GÓMEZ, RODRIGO; VICINO, PAULA; CARRILLO NÉSTOR; CARRILLO, JULIETA; LODEYRO, ANABELLA

Encuentro; LVI SAIB Meeting?XV SAMIGE Meeting; 2020

With the notable exception of angiosperms, all phototrophs contain different sets of flavodiiron (Flv) proteins which help torelieve 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 alleviates 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 SynechocystisFlv2-Flv4 in chloroplastsof 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 indicatethat 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-flv4genes constitute a novelbiotechnological tool to generate plants with increased tolerance to agronomically relevant stress conditions that represent a significant productivity constraint