Putative model of the regulation mechanisms involved in HL acclimation in Synechococcus 7002. Proteins colored in yellow were indispensable upon HL stress. CrtU, beta-carotene desaturase; HemF, coproporphyrinogen III oxidase; HemJ, coproporphyrinogen III oxidase; PcyA, phycocyanobilin:ferredoxin oxidoreductase; ChlM, Mg-protoporphyrin IX methyl transferase; Hox1, heme oxygenase (decyclizing); Por, protochlorophyllide oxidoreductase.