Providing an Additional Electron Sink by the Introduction of Cyanobacterial Flavodiirons Enhances Growth of A. thaliana Under Various Light Intensities

TULA, SURESH; SHAHINNIA, FAHIMEH; MELZER, MICHAEL; RUTTEN, TWAN; GÓMEZ, RODRIGO; LODEYRO, ANABELLA F.; VON WIRÉN, NICOLAUS; CARRILLO, NÉSTOR; HAJIREZAEI, MOHAMMAD R.

Frontiers in Plant Science

Frontiers

Año: 2020 vol. 11

The ability of plants to maintain photosynthesis in a dynamically changing environmentis of central importance for their growth. As the photosynthetic machinery is a sensitiveand early target of adverse environmental conditions as those typically found in thefield, photosynthetic efficiency is not always optimal. Cyanobacteria, algae, mosses,liverworts and gymnosperms produce flavodiiron proteins (Flvs), a class of electron sinksnot represented in angiosperms; these proteins act to mitigate the photoinhibition ofphotosystem I under high or fluctuating light. Here, genes specifying two cyanobacterialFlvs have been expressed in the chloroplasts of Arabidopsis thaliana in an attempt toimprove plant growth. Co-expression of Flv1 and Flv3 enhanced the efficiency of lightutilization, boosting the plant?s capacity to accumulate biomass as the growth lightintensity was raised. The Flv1/Flv3 transgenics displayed an increased production ofATP, an acceleration of carbohydrate metabolism and a more pronounced partitioningof sucrose into starch. The results suggest that Flvs are able to establish an efficientelectron sink downstream of PSI, thereby ensuring efficient photosynthetic electrontransport at moderate to high light intensities. The expression of Flvs thus acts to bothprotect photosynthesis and to control the ATP/NADPH ratio; together, their presence isbeneficial for the plant?s growth potential.