A Specific Single Nucleotide Polymorphism in the ATP Synthase Gene Significantly Improves Environmental Stress Tolerance of Synechococcus elongatus PCC 7942

Two closely related Synechococcus strains showed significantly different tolerances to high light and high temperature but limited genomic differences, providing us opportunities to identify key genes responsible for stress acclimation by a gene complementation approach. In this study, we confirmed that a single point mutation in the α subunit of F o F 1 ATP synthase (AtpA) contributes mainly to the improved stress tolerance of Synechococcus elongatus UTEX 2973. The point mutation of AtpA, the important ATP-generating complex of photosynthesis, increases AtpA protein levels, intracellular ATP synthase activity, and ATP concentrations under heat stress, as well as photosystem II activity. This work proves the importance of ATP synthase in cyanobacterial stress acclimation and provides a good target for future improvement of cyanobacterial stress tolerance by metabolic engineering.